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by Conleth on Tue May 14, 2019 11:55 am
Nick Fury was more than happy to offer SHIELD's services...for a price. Tony and Steve had had to sit through a rather lengthy debriefing and at the end of it Nick wasn't particularly pleased that Dr. Doom walked away with an ancient book of Black Magic and a bar of Uru. It was a shame that Thor and Pharoah weren't there or likely this entire thing would have likely gone the opposite way.
Serena was in a hospital bed and there was a heart monitor and IV attached to her. The infirmary looked like any other hospital by all accounts though perhaps a bit more high tech. There were several nurses and 2 doctors who oversaw the small line of rooms and in some of the other rooms SHIELD agents were there recuperating after being injured while on duty.
Serena had lines all over her body and face that looked as if her veins had turned a dark gray in places. Some of her skin had second degree burns as well but for those, twice a day she is submerged into a large bath like apparatus that Fury said would repair her skin without scarring. For the other problem they had called in their Dark Matter Specialist Dimitri Cullen. He was tall and thin with brown and gray hair. An older man with dark eyes that held a vast amount of intelligence. His son Evan was also there, a younger version of himself with longer, wavy black hair and darker skin. An attractive young man that could actually manifest and control Dark and negative Energy. While Dimitri was dressed in his usual lab coat, white shirt and black trousers, Evan was in a tight knit black long sleeved shirt and black cargo pants bloused into black leather boots.
Across the hall Malcolm was there, the right side of his face was badly bruised and a facial bone had been fractured. He had a severe concussion as well and they had to put him into a coma to help reduce the swelling of his brain. In some ways he was in more danger than Serena but the oddness of her injuries required a specific kind of treatment.
Natalya, Peter, Steve, Isabella and Kate were all seen to for their far lighter injuries and all of them were released within the same day that they were seen. Natalya did not have a concussion it turned out, her heightened durability from the soldier serum had protected her from any lasting effects of her head wound. She did need stitches though.
As the doctor was finishing up on her Logan was there in his usual Jeans and white t-shirt. "You're gettin soft Nat, did ya get a lil boo boo?" he teased, trying to lift her spirits but it appeared to him that she was still worried about Malcolm. There was a short silence then he began again. "His face was always to pretty, and considering how much you two argue I'd say his head's to hard anyway for ya," He added.
Re: The Healing Process
by XslvrstarX on Tue May 14, 2019 12:37 pm
Isabella was extremely worried about Serena. Serena continued to fall in and out of consciousness, but at least she didn't seem to be getting any worse...at least she hoped that was the case. The skin that had been burned she know could be healed, but it was the dark grey lines all over her body that Isabella was worried about. And so was SHIELD it seemed because they had called in a Dark Matter Specialist named Dimitri Cullen.
Isabella had gotten through the fight with a fractured wrist and a cut on her right side. She and Tony spent hours by Serena's side and when they couldn't be there Peter was always ready to step in and take their place. Isabella had known that the pair had grown very close recently, but was starting to wonder if there wasn't something deeper between them. She didn't question Peter about it though. She would just watch him as he sat close to Serena and took her hand into his own. There was something in the way he looked at Serena though that reminded her of how Tony would look at her.
Kate was one of the few who had gotten through the fight with very little injuries. She hadn't turned over the shield she had taken from one of Doom's guardian's and instead had kept it and hidden it in the Tower. Natalya was also pretty well off. She had hit her head pretty hard, but didn't have a concussion. She did have to get a few stitches in her left arm from where she had been hit by falling debris. The wound would heal quickly though thanks to the Super Soldier Serum in her blood.
The doctor had just finished stitching her up when Logan appeared. Natalya rolled her eyes a little at his comment, but was too worried about Malcolm to really say something back. "I should really go check on him," she said as she hopped down off the table. She stepped out of the door just as someone was passing by and the two of them collided. Natalya quickly regained her balance. "I'm so sorry....Evan?"
by Conleth on Tue May 14, 2019 1:51 pm
Natalya had come into Evan's life as sudden as she left. He had been working for SHIELD when he met her and she had been working for the SSB and they were both being hunted by a mutant that they had never heard of or seen before. At some point in their desperate fight for survival and evasion they had fell for one another hard. At least, Evan had fell for her. Evan was a few years younger than she and he possessed a dark disposition at the time that seemed to call to her. A side effect from his particular affliction and kinship with Dark Energy and Shadows. One morning however she had gone and he had never saw her again...until now. Without thinking he took hold of her face and kissed her...quite deeply. He felt her hand and with a soft, but firm shove she managed to push him off of her but there was something he saw in her eyes. A mix of emotions he could not discern right then. It was then that he noticed that they weren't alone. Whenever he was even close to her she ignited his passions.
"Natalya?! I never thought I'd see you again," he said and looked over toward Logan who scowled at them. Logan caught Natalya's eyes. "Seriously? Him to?" Logan said and she'd know what he was thinking of calling her right then but thankfully he didn't. Logan looked sincerely puzzled. An older man with glasses and a lab coat poked his head from Serena's room. "It's time son, she's prepped for another treatment," he said plainly and didn't take Natalya nor Logan into his gaze at all. Evan did not look at him he only had eyes for Natalya. His large, dark eyes seemed to drink her in she would know he wanted to kiss her again...badly by how he was looking at her. "I'll be right there father," Evan said. And then his demeanor changed as thought and remembrance finally came into his head.
"So, you're no longer with…" He began but stopped realizing they were not alone. "Evan!
His father called annoyedly from the room. "I've got to go...a young woman is dying from…" He had started to say but stopped not knowing why she was there. Was it for the young woman or the man in the next room? He wondered silently. "I want to talk later...alone," he said demandingly and spared Logan a neutrally cool look before he turned and stepped away into Serena's room.
by XslvrstarX on Tue May 14, 2019 3:25 pm
Natalya was stunned to see Evan. He was just as she had remembered him and just as handsome...if not more so now. They had had a fast, passionate relationship that, much like her relationship with Malcolm at the moment, had been built on desire alone. Before she could say a word he put his hands on the side of her face and kissed her...hard and passionately. She could not stop herself and did kiss him back, but only for a moment before she managed to push him away. Feeling his lips on her own again and looking up at him she felt...something stir inside of her that was beyond desire. She wanted to say something to him...to tell him she was sorry for leaving in the middle of the night as she had...to ask him how he had been. Suddenly, she saw a man that she recognized from a picture as Evan's father pop his head out of Serena's room and call for Evan. She knew his father was a Dark Matter specialist and it concerned her that he and Evan were here for Serena. What had Doom done to her? She nodded a little when Evan said he wanted to speak to her later and watched as he walked into the room.
She stood there for a moment as the realization that Serena might not make it through this began to sink in. She then looked up and saw Peter and from the look on his face she knew he must have also heard what Evan had said. She walked over and put a comforting arm around him. "She's gong to be fine Peter. She's in the best hands she can be at this point."
Tony and Isabella has gone back to the tower to oversee repairs, shower, eat and get a few hours of sleep. Peter was a godsend being completely available to watch over their daughter. Tony's respect for the kid had grown tremendously over the past few days and he could see how much he cared for Serena, their daughter.
Peter looked at Natalya and Logan uncertainly and he looked like someone who hadn't slept much that last few days.
"Natalya...is Serena going to die?" He asked plainly though his voice broke in the middle of that sentence. Logan frowned at him. "Ofcourse not kid. She's a Stark through and through," he said and clapped him on the shoulder. "You go get a bite to eat, I'll watch over her for you," Logan said. Peter had that look of loss and profound sadness as he looked up at Natalya.
Evan couldn't get Natalya out of his head one moment they were lovers and the next she was gone. He didn't blame her for leaving, he knew what she was up against. The SSB were ruthless. Seeing her again was amazing for him. And he hoped she didn't pull another disappearing act like last time.
"Evan, I want you to try drawing out the Dark Matter from her flesh. Not quickly mind, very slowly," Dimitri said. From out in the hall, they heard Serena begin to scream.
Natalya honestly didn't know the answer to that question. She hoped not. Serena meant a lot to everyone in that Tower. She couldn't even imagine what Tony and Isabella would do if Serena didn't make it through this. But they couldn't give up hope and she needed to be strong for Peter...just as she was strong for everyone else. She glanced over at Logan as he reassured Peter and felt a wave of gratitude come over her.
"Come on Peter," she said after Logan suggested he go get something to eat. "I'll go with you." However, in that moment she suddenly heard Serena begin to scream. She looked at Logan and then looked back at Peter. "Stay here Peter."
She quickly walked into Serena's room and looked at Evan. "What the hell is going on?"
by Conleth on Wed May 15, 2019 8:36 am
The hospital room was like the others. Monitors and devices on the wall. A bed, a bedside table and a rollable table moved to the side. There were a few other chairs as well as a door that led to a small bathroom. One of the nurses was there trying to hold down Serena's arm. No...trying to restrain her left arm. The right had a leather restraint on it already. And her ankles. She was in a white, hospital gown and the white sheet and blanket had been kicked to the side of the bed. Dimitri was on the other side of the bed putting something by syringe into her IV while Evan was at the foot of the bed. Something hovered over the bed, a dark cloud it looked to Natalya. Evan was connected to it as if by a tendril and a tendril of it was connected to Serena as well. Evan's eyes were solid black and she knew he was using his power. For she had seen it before.
"Get out!" Dimitri said angrily but it was clear that Natalya was going nowhere. The black tendril that touched Serena seemed to be flowing out of her while the one that touched Evan flowed into him. With the dark cloud between them roiling like it was alive. As moments passed Evan's flesh took on that same look as Serena's did where his veins seemed to turn black. Her veins appeared less black, paler then they had been but it was obvious she was in agony as Evan drew out whatever it was that poisoned her. After a few more moments Evan stopped and clutched his forearm. Serena fell silent and still and the dark cloud began to dissipate in wispy waves that flowed up into the room.
Evan's eyes were still black and as he clutched his forearm he seemed to be struggling with...something. He was absorbing the dark energy and he winced as if he were in real pain. His face was slick with sweat and as he appeared to struggle with whatever was happening to him he fell to his knees. His father only stood there and watched s he scribbled emotionless on his clipboard. Eventually Evan seemed to succeed in whatever he was trying to do and as the blackness in his veins faded away he fell onto his side and his eyes turned back to normal. He panted as he rested his head on his arm, as if he had just ran a marathon. Serena's already looked better but her eyes were closed and she had sweat through her gown.
Behind her Peter darted in and covered her up with the blanket. "What the hell are you doing!" He said angrily as he began to release her from the restraints. When the nurse tried to help him he shoved her back. "Don't you touch her!" He growled. Logan was still in the hall. "Is..everything alright?" he asked concernedly as he frowned as he looked at Evan on the floor.
by XslvrstarX on Wed May 15, 2019 9:56 am
Natalya was not one to normally feel fear. Fear was considered a weakness as far as the SSB was concerned and they did not create her to have weaknesses. However, that day she did feel fear. She felt fear that Serena was going to die before her eyes...and she felt fear that Evan was going to die before her eyes. She did not move...or perhaps could not. She just watched in silence as Serena writhed in pain while Evan drew out the Dark Matter from her body. She had seen Evan do this before but that did not make it any easier. She felt helpless and unsure of what to do, a feeling she wasn't used to. It was a feeling she did not like.
Finally, it was over and right before her eyes Serena's color began to return to normal. She was drenched in sweat and unconscious, but her vitals were holding steady. She was glad that Tony and Isabella hadn't been here to witness that. She wasn't sure how they would have reacted. As it was she could not hold Peter back from going to Serena. He seemed extremely upset, an emotion she wasn't used to seeing in him. His feelings for Serena were clear to her now and she tired to comfort him. "She's alright Peter. It's over now and she'll be fine...back to her normal self before you know it. She just needs to rest and recover."
Natalya glanced over at Logan, who was standing in the doorway and then looked back at Evan. No longer caring what he thought, she quickly walked over to Evan and knelt down beside him. "Evan, are you alright?" There was genuine concern in her eyes for him.
by Conleth on Wed May 15, 2019 12:09 pm
Evan looked up at Natalya as she knelt down in front of him. He looked pale, sweaty and exhausted but his eyes looked clear. Their eyes met and he looked into her dark eyes and didn't want to look away. Just her being this close seemed to give him strength and calm.
"Remarkable," Dimitri said as he looked over Serena. He didn't even glance at Evan as he began writing again in his clipboard. "Help me up," He asked and was thankful Natalya did. "It takes time to absorb...that much…" He said in a throaty voice. "Nick told me what had happened. It is a wonder there were only 2 casualties. We've all heard of Dr. Doom," He said and his throat appeared to be clearing. Even as she held onto his arm he seemed to waiver and Natalya brought her other hand over to steady him.
"It...takes alot out of me to do...what I just did. I need food and alot of it," Evan said and he turned his gaze toward Logan. He didn't know who the man was, SHIELD only gave out information when they thought it was completely necessary. He didn't know who the young man was either...the sick woman's boyfriend or brother? "She will sleep for a time but I may need to do this again to get rid of it all within her," he said weakly.
by XslvrstarX on Wed May 15, 2019 1:22 pm
Natalya listened closely to what Evan said about Serena and nodded. She looked over at Peter and could tell that there was not likely going to be any way of separating him from Serena's side at this point. "Logan," she said in a low, soft voice, "will you stay with Peter?" When he nodded she turned her attention back to Evan and helped him out of Serena's room. Together they went to SHIELD HQs dining hall and she got Evan something to eat before getting something for herself. She had chosen a table in a corner near one of the windows. It was away from everyone else. She sat down across from Evan and at first wasn't sure what to say.
"That was Serena Stark, Tony and Isabella Stark's daughter and only child. She was unfortunately targeted during the attack. To be honest I wasn't sure if she was going to survive."
by Conleth on Wed May 15, 2019 1:58 pm
The Cafeteria was actually quite nice. Painted in soft earth tones with a large salad bar which included the day's selections, juice bar, soda fountain and a small mart area with drinks and foods ready to eat. Evan had packed alot of food on his tray and the contrast between what he had and what Natalya had was nearly laughable. He was thankful she chose a place away from everyone else. There were several SHIELD personnel in the cafeteria but they knew Evan if only by sight and seemed to ignore them.
"Oh...well..uh, she's a strong young woman...I suppose that makes sense she's a Stark. I won't apologize if you were worried. I had to try or she would have died. Our bodies are not designed to absorb so much Dark Energy...similar to say radiation. She absorbed perhaps...as much dark energy as say.. Standing near the center of chernobyl during the disaster," he said as he shook his milk. He opened it then gulped it down until it was gone. He closed his eyes for a moment and she visibly saw his color improve. Evan was normally somewhat tanned in his complexion.
"Ok..that felt good," he said then looked up and saw her looking at him. "So...none of that explains why you're here, though I am happy to see you again, Natalya," he said almost in that way he did when they were last together. His tone carried the affection he felt for her. And she knew Evan did not hide his feelings unlike most men. He was confident in that way.
Natalya knew that it had been a lot of energy that Serena had absorbed but having that comparison was eye opening. She wondered if there would be any permanent effects from all of this, but at least it looked like Serena was going to survive.
Natalya opened up her bottle of water and took a sip before looking at Evan. There was something about the way he looked at her that made her feel...she wasn't sure what the word was but she definitely felt it. "I'm apart of the Avengers team now," she told Evan. "After I left you that night I went back to the SSB and began killing people again. Logan, the grumpy looking guy who was in Serena's room with me, was sent to track me down and kill me. He made a different call and spared my life. He brought me back to talk to Steve Rogers and they decided to give me a chance to change. It hasn't been easy and the SSB is now hunting me, but I think I'm doing alright."
Evan listened intently as he ate. If it wasn't her telling her story he would not have believed it. She was part of the Avengers. He would never have guessed that in a million years. As she talked Evan had managed to eat a pudding, half a sandwich. a piece of pizza and a piece of apple pie.
"So the SSB are still after you," he whispered. "I suppose they might always be," he said as he looked at her. "I know why you left that night. I..I just thought there was something happening between us. I guess we just didn't have time," he said but there was more to his words then that. He was fishing. Fishing for how she felt about all of that. She could have just been with him for convenience at the moment. Using him to evade the people chasing her…and himself.
Natalya wasn't feeling overly hungry today. She felt confused about her emotions at seeing Evan again. She and Malcolm had something between them, but she wasn't honestly certain what it was. She pushed her tray away, uneaten and looked at Evan. "There was something happening between us Evan, but I couldn't stay with you. I'm honestly still trying to figure things out in my life. I do still feel...something for you...but I also have something going on with another guy."
Evan smiled at her when she said she was seeing someone. It meant that she was at least trying for some form of normal. If that was even a thing for people like them. "Well...that's a good thing, isn't it? Two men. maybe 3 want you and have no ulterior motives. Well, if other than just being with you," he said. And his smile grew.
"For myself I've just been laying low. Working for SHIELD and helping my father with his research on Dark Matter," he said. "Not very exciting..Not like being an avenger," he said.
by XslvrstarX on Wed May 15, 2019 10:14 pm
Natalya looked at Evan with affection in her eyes. Evan had never judged her and had accepted her for who she was without wanting to change her. He had just wanted to be with her...just as he did now.
She gave him a little smile when he talked about her being an Avenger. "Well, you know we are always looking for more help. The dangers the world is facing nowadays is greater than it has ever been. I could put in a good word for you with Tony and Steve..,"
"I might be interested...So what can you tell me about the young woman. What exactly happened to her? Only asking because we aren't certain if there won't be...side effects of such a large infection. What was the nature of her injuries?" He asked. When she explained and described what Doom did Evan was both intrigued and even more concerned.
"If Doom used dark magic...he could be tapping into powers that he has no idea of their effects. Touching such a source infects the one touching it as well. I can touch it without a lasting effect upon me but you saw what trying to take it into myself did to me. He's like a child playing with fire. And I doubt he'd listen to anyone. He is likely strong to channel that much energy," he said.
by XslvrstarX on Thu May 16, 2019 7:17 am
Natalya explained what happened to the best of her ability. She had not been conscious during the attack on Serena and only knew what happened through Tony, Isabella, and Peter. It sounded horrifying. It didn't help matters that Evan didn't seem to be sure what long term effects she might suffer as a result of this.
"Tony ended up giving Doom what he wanted just to get him to stop. It was a book of magic and a bar of Uru. We are all worried about what he might do with these, particularly if he is already strong enough to do what he did to Serena."
by Conleth on Thu May 16, 2019 7:58 am
Evan's concern seemed to grow exponentially as Natalya told him what Dr. Doom was after. "Wielding that much...The man's insane," he said and he discovered he was no longer hungry. He also noticed Natalya's thoughtful frown.
"Ok, enough talk about...unpleasant things," He said and on impulse he reached over the table toward her and took up her hand in his. "I'm quite impressed you've joined the Avengers. I did not see that for you...before," he said and smiled at her. He didn't go into the implications of that. He knew her past and he also knew that SHIELD knew her and if they allowed everything to come to pass then she was in a much better place than she had been. He had read her file and though she had done horrible things what bothered him most was the pleasure it brought her, sometimes. Pride in one's work in her case though involved violence and espionage. Difficult not to take her to task for the things she's done but the SSB had taken her from birth and molded her in their image. Now, it appeared that she was eschewing that mold and he had to give her credit for that. He had seen her fighting abilities first hand. She had almost killed him after all and she pummeled him as if he were just a child. He had more hand to hand training since but one look at her solid physique and he knew, if anything she was harder now.
"So If I do decide to join I'll stay where you stay?" He said with a grin that insinuated that he would be close to her then. His grin faded though recalling what she had said about another guy. "Perhaps we could...at least be friends," he said and released her hand though he certainly didn't want to.
Natalya watched as Evan reached out and took her hand into his own. She didn't pull hers back and felt his thumb gently caress her skin. She and Evan had been through a lot together in a short period of time. Even though he had known about her past and what she had done, he had protected her and for that she was eternally grateful. She knew that her past bothered him, but he had never said anything to her. Evan had come into her life when she had needed someone the most and she began to wish that things had ended differently between them...or not at all.
Natalya felt Evan release her hand and she found the sudden loss of it...painful. She felt confused about her feelings for Evan...and for Malcolm. Could she love them both? Her emotional turmoil was evident in her eyes for a moment before she managed to fight it back. "Yes...we can be friends." She paused a moment and looked into his eyes before looking away slightly. "The way joining the team works is that first Tony and Steve have to decide if they think you would be right for the team. Then, the entire team gets together and each person votes 'yes' or 'no'. The entire team has to say 'yes' for you to join. One 'no' and that's it...you're not apart of the team."
Evan walked Natalya back to the recovery ward. Tony, Isabella, and Logan were there talking with the SHIELD doctor that was taking care of Malcolm. "I have to go but if Serena Stark doesn't improve I might need to repeat what I did. I hope to see you again Natalya," Evan said and then hugged her before he left.
Kate stepped out of Serena's room and joined the small gaggle in the hallway. As she arrived she had the sense that there was someone else nearby. Someone in Malcolm's room. A woman with long, dark hair. Her back was to the door however so she could not see who it was. There were several MRI scans attached to the wall just outside the room and they were all lit up.
"So we found the bleed," The doctor said as he looked at the newcomer. "Finally but the outlook is not great do to where it is located," he said as he used a red dot pointer to explain the situation. "A damned if we do, damned if we don't situation," he said. "The aneurysm is moving slowly and right now it's located into this cluster here, a delicate area to go digging around to remove it," He said.
Logan watched Natalya as she arrived and his expression was completely neutral. "All of SHIELD's technology and we're still talking about traditional surgery?" Tony asked but it wasn't really a question. "Mr. Stark we have several experimental methods we are working on but they are not ready for human trials," he said. "What are his chances?" Isabella asked and everyone's gaze shifted up to the doctor. Steve appeared at the door of Serena's room and Pharaoh was behind him still inside the room.
by XslvrstarX on Thu May 16, 2019 10:41 am
Natalya hugged Evan back and watched him as he stepped away. She found everyone else from the team standing in the hallway outside of Malcolm's room. There was a doctor there as well and as she approached she could tell that he was talking about Malcolm. Her breath caught in her chest as she heard the doctor's prognosis. She didn't really know what to say and felt a wave of fear come over her at the thought of losing him. She did truly care about him and felt, in some way, that this was her fault because she had agreed to let him on the team when she could have just said no and protected him.
Kate moved over to Natalya and put an arm around her shoulders and rubbed her arm as they waited for the doctor's response to Isabella's question. Kate was curious as to who the woman was that was in Malcolm's room, and wondered if she might be family.
by Conleth on Thu May 16, 2019 12:03 pm
"50/50 I would say," the doctor said. The woman that was in Malcolm's room had stood and heard what the doctor said. She walked up to him and her face was an angry glare. "50/50? Where the fuck is Nick Fury?! How did this happen to my brother?!" She nearly screamed. She had tears in her eyes and her lips trembled with the effort to not weep uncontrollably in front of these people. By the redness in her eyes and face she had done alot of that already.
"Nick Fury's not at fault," Steve said though he only guessed she was Malcolm's sister. "I am," He said solemnly. The woman seemed to recognize Steve even though he was in civilian clothes and her gaze took in the others. "Steve that's not…" Tony began but Steve cut him off. "He was my responsibility and while we engaged a dangerous and powerful mutant, Malcolm was injured. Malcolm and the young woman across the hall," he said softly but also levely. "I'm sorry," Steve said sincerely and the woman ducked her face down into her hands and began to cry. "Not him...not my Malcolm!" She wailed.
by XslvrstarX on Thu May 16, 2019 1:38 pm
Natalya's expression became extremely solemn. Her gaze dropped to the floor as a mixture of emotions began swirling around inside her heart. She needed to hold out hope though that he would make it through this.
Kate looked over at the woman who identified herself as Malcolm's brother and then at Steve when he tried to place the blame of what had happened on his own shoulders. "Steve, this is not your fault. Our jobs are risky and he knew that coming in. There is always a chance that something is going to happen to one of us. It was his choice."
Natalya shook her head and then swallowed hard and looked up. "No, this is my fault. I could have voted no and kept him out of danger, but I didn't."
by Conleth on Thu May 16, 2019 2:19 pm
"Bullshit, we all voted yes," Logan said. "This is on Doom's head, no one elses and throwing around responsibility won't change anything. No one made Malcolm's choices for him and none of us have the right to take responsibility for them. A good man was hurt doing what he thought was right," He said though he didn't really know why. He didn't really like Malcolm but that had nothing to do with his sacrifice.
Peter Held Serena's hand. Her veins looked paler then they had just a few hours ago and her general palor seemed to be turning into a more healthy color. "You have to stay with me Serena," he whispered. "I won't let you go so easily," he said. Her vitals were getting stronger as well form what the doctor had said. What Evan did removed enough of the dark energy for her own body to absorb the rest. Not necessarily a good thing if she were exposed to it again but she would live.
Serena's eyes opened and saw Peter there at her bedside.
» general of snatchins???
» New section for players to organise Boss fights or to Heal General?
» sweet spot - statistics and probability in engine tourney


text:
Numerical Analysis of Influence of the Hull Couple Motion on the Propeller Exciting Force Characteristics
Frequency Domain Response of Jacket Platforms under Random Wave Loads
JMSE
10.3390/jmse7100329
Hole, L. Robert
Dagestad, K.
Röhrs, J.
Wettre, C.
Kourafalou, V. H.
Androulidakis, Y.
Kang, H.
Le Hénaff, M.
Garcia-Pineda, O.
J. Mar. Sci. Eng. 2019, 7(10), 329; https://doi.org/10.3390/jmse7100329
The DeepWater Horizon Oil Slick: Simulations of River Front Effects and Oil Droplet Size Distribution
by Lars Robert Hole 1,* , Knut-Frode Dagestad 1,† , Johannes Röhrs 1,† , Cecilie Wettre 1,†, Vassiliki H. Kourafalou 2,†, Yannis Androulidakis 2,†, Heesook Kang 2,†, Matthieu Le Hénaff 3,4,† and Oscar Garcia-Pineda 5,†
Norwegian Meteorological Institute, Allegt. 70, 5007 Bergen, Norway
Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA
Cooperative Institute for Marine and Atmospheric Studies, University of Miami, Miami, FL 33149, USA
NOAA Atlantic Oceanographic and Meteorological Laboratory, Miami, FL 33149, USA
WaterMapping, Gulf Breeze, FL 32563, USA
Correspondence: [email protected]; Tel.: +47-55236600
These authors contributed equally to this work.
Received: 28 July 2019 / Accepted: 18 September 2019 / Published: 22 September 2019
Browse Figures
The effect of river fronts on oil slick transport has been shown using high resolution forcing models and a fully fledged oil drift model, OpenOil. The model was used to simulate two periods of the 2010 DeepWater Horizon oil spill. Metocean forcing data were taken from the data-assimilative GoM-HYCOM 1/50° ocean model with realistic daily river input and global forecast products of wind and wave parameters from ECMWF. The simulations were initialized from satellite observations of the surface oil patch. The effect of using a newly developed parameterization for oil droplet size distribution was studied and compared to a traditional algorithm. Although the algorithms provide different distributions for a single wave breaking event, it was found that the net difference after long simulations is negligible, indicating that the outcome is robust regarding the choice of parameterization. The effect of removing the river outflow was investigated to showcase effects of river induced fronts on oil spreading. A consistent effect on the amount and location of stranded oil and a considerable impact on the location of the surface oil patch were found. During a period with large river outflow (20–27 May 2010), the total amount of stranded oil is reduced by about 50% in the simulation with no river input. The results compare well with satellite observations of the surface oil patch after simulating the surface oil patch drift for 7–8 days.
HYCOM; OpenDrift; OpenOil; oil spill; modeling; simulations; satellite; observations; river fronts; DeepWater Horizon
The synergy between shelf and open sea dynamics makes the Northern Gulf of Mexico (NGoM) a topographically and dynamically complex and interesting study area, in the presence of intense oil exploration [1,2]. Interactions of the Mississippi River (MR) plume and the Loop Current (LC) system were found to be important for the transport and fate of oil during the 2010 DeepWater Horizon (DWH) accident [3,4].
According to the U.S. Energy Information Administration, more than 45% of the total U.S. petroleum refining capacity and 51% of the total natural gas processing plant capacity are located along the northern Gulf coast [5]. Oil leaks and accidents, such as the explosion on the DWH platform in 2010 (at 28.737° N, 88.366° W), have released significant quantities of hydrocarbons [6,7] in the sensitive marine environment around the MR Delta, and over the LouisianA TEXas (LATEX) and Mississippi Alabama FLoridA (MAFLA) shelves [3] (Figure 1).
The present study was motivated by recent advances in the understanding of the role that salinity induced fronts and circulation areas dominated by river plume dynamics may play in the transport of hydrocarbons [3,8]. We used a comprehensive high resolution modeling system to demonstrate reliable estimates of hydrocarbon transport under the influence of all circulation driving mechanisms, with an emphasis on correctly accounting for fronts and circulation patterns due to river plume influence. Such fronts are density-driven, but also related to distinct circulation regimes that characterize river plume dynamics and may even control near-surface transport, subject to strong variability under the influence of additional shelf and deep sea flows. The river induced, buoyancy-driven flows include a westward coastal current along the LATEX shelf ("downstream" plume regime, i.e. in the direction of Kelvin-wave propagation) and a northeastward flow toward the MAFLA shelf ("upstream"). The former is due to the geostrophic balance between Coriolis and cross-shelf pressure gradient (e.g., [9,10,11]) and is enhanced by downwelling-favorable winds; such conditions favor material entrainment and nearshore confinement due to mass balance considerations. The latter is due to the balance between along-shelf pressure gradient and along-shelf acceleration [9]. This coastal flow has a tendency to turn offshore, enhanced by westerly upwelling-favorable winds; such conditions promote material removal away from the coastal zone, while they restrict material from offshore sources to reach the coasts. The third important flow regime, the buoyancy-driven anticyclonic bulge, is often suppressed due to the Mississippi Delta proximity to a steep slope ([12,13]) and it is usually formed under high discharge conditions [3]. These flow regimes induce well defined fronts that exhibit strong variability, depending on river discharge, winds and interaction with offshore flows [13]. These are relevant to pathways of any "materials", such as river-borne (e.g., nutrients) or from offshore sources potentially driven within plume influence (e.g., hydrocarbons from neighboring exploration sites). River induced fronts and related circulation regimes are hard to monitor and are often not well represented in numerical models. In the Gulf of Mexico (GoM), this is a particularly difficult task, due to complexity in topographic controls and direct influence of large scale oceanic currents (e.g., the LC and associated eddy field) on plume induced transport ([3,13]). Related transport pathways may have great impact on coastal ecosystems in the vicinity of GoM areas with river influence (especially over NGoM), but also remote ecosystems that can be reached along the LC (such as the South Florida islands and reefs, e.g., [14,15,16]). In the simulations presented herein, we employed a detailed representation of river plume dynamics, thus the related circulation features and fronts are well described.
Many studies have dealt with simulations of the DWH spill [3,4,17,18,19,20,21,22,23] with focus on both subsurface [21] and surface [4] transport. North et al. [17] used a plume model to predict a stratification-dominated near field, in which small oil droplets detrained from the central plume containing faster rising large oil droplets and gas bubbles and became trapped by density stratification. They showed that simulated droplets with diameters between 10 and 50 μm formed a distinct subsurface plume, which was transported horizontally and remained in the subsurface for >1 month. In contrast, droplets with diameters >90 μm rose rapidly to the surface. Le Hénaff et al. [4] focused on oil transport on the water surface and showed that the wind played a major role on oil spreading over the NGoM. Barker [20] conducted Monte Carlo simulations consisting of 500 individual oil trajectory scenarios using historical data of water currents and winds. The results by Barker [20] indicate that, in approximately 75% of the scenarios, oil would be transported out of the GOM by the LC. This means that the actual trajectory of oil from the DWH falls in the 25% of scenarios.
Androulidakis et al. [8] carried out a field experiment deploying surface drifters at different times near the Taylor Energy Site, which is located in the vicinity of the MR outflow region over the NGoM and near the DWH site (approximately at 28.938° N, 88.978° W, Figure 1). This multi-platform observational experiment was conducted in April 2017 to investigate the main transport pathways from the Taylor Site either toward the NGoM continental shelves or offshore, toward the Gulf interior. The results indicate that the surface transport was determined by the MR plume extension over the Taylor Energy Site and the river induced fronts in combination with local circulation, prevailing winds and broader regional dynamics (LC system). The drifters, deployed during the field experiment in tandem with satellite data, drone imagery, wind measurements, and marine radar observations (surface currents and oil), described three main transport pathways, in agreement with the three prevailing circulation patterns of the MR plume [10,13,15,24].
The drifters followed the two prevailing coastal currents associated with MR plume dynamics (downstream/upstream moving westward/eastward of the Mississippi Delta) and an offshore pathway under the influence of basin-wide circulation (LC system). Near the Taylor site, the existence of multiple river fronts influenced the fate of oiled waters, preventing the transport of hydrocarbon toward the delta similar to a natural boom barrier, trapping and directing the oil either westward or eastward in agreement with Kourafalou and Androulidakis [3], who showed a similar interaction during the DWH accident using hydrodynamic numerical simulations. In situ thermohaline measurements around the Taylor Energy Site and across the river front showed that the MR plume near the Taylor Site was 5–10 m deep, while the clearer ocean water column was characterized by a 40 m upper-ocean homogeneous layer, mainly controlled by temperature [8]. Herein, we extend these observational and ocean modeling studies by conducting numerical simulations with a state-of-the-art oil spill model to investigate the river front effects on the evolution of the DWH oil spill in the summer of 2010.
Much progress has been made after the DWH accident in understanding the GoM ecosystem, the physical oceanography and its economic significance [1,25]. In this study, an open source Lagrangian oil drift model, OpenOil, was used to simulate the DWH oil spill evolution. OpenOil takes into account major factors that influence the short term drift of surface oil slicks such as metocean forcing (including Stokes drift), emulsification, evaporation, vertical entrainment and mixing. Simulations were initiated from satellite observations and a point source at the sea floor. The initialization of simulations from satellite observations is a relatively new feature in operational marine oil spill modeling [26], although pioneering work was carried out by Liu et al. [22] and Liu et al. [23] shortly after the DWH spill in 2010. The effect of two different oil droplet size distribution on the horizontal drift and vertical mixing is discussed. This study showcases how NGoM oil pathways are influenced by river plume dynamics and river induced fronts. Whether the use of realistic daily river discharge has a significant effect on the simulated location of the Surface Oil Patch (SOP) and stranding of oil was also investigated.
2.1. Shapefiles of Surface Oil Patch
Shape files derived from satellite analysis of the DWH SOP can be accessed through the NOAA-ERMA website [27]. In the present study, oil elements were seeded uniformly within the region enveloping the thick and thin oil slicks with no distinction. The shapefiles were used here for both initialization of the oil drift simulations and for verification of results.
2.2. Metocean Forcing
In the cases presented here, the ocean circulation fields came from a data-assimilative, high- resolution (1/50°, 1.8 km) configuration of the Hybrid Coordinate Ocean Model [28] in the GoM, developed by the authors (GoM-HYCOM 1/50). GoM-HYCOM 1/50 uses daily river forcing and data assimilation. The HYCOM model has a flexible, hybrid vertical coordinate system, in which the distribution of vertical layers is optimized: they are isopycnal in stratified water columns, terrain- following sigma in regions with sharp topography, and isobaric in the mixed layer and very shallow areas [29]. More information about the HYCOM model is available in the model user's manual ([28] and references therein). The GoM-HYCOM 1/50° covers the entire GoM and uses 32 vertical layers. This model configuration is similar to the one used by Le Hénaff and Kourafalou [30], with the realistic river forcing parameterization developed by Schiller and Kourafalou [10]. The river discharge data were obtained from the Army Corps of Engineers and the U.S. Geological Survey. The model is initialized in October 2009 with fields from the operational GLoBal HYCOM simulation run at the Naval Research Laboratory at the Stennis Space Center (GLB-HYCOM expt_90.8, [28]), and it is nested at the open boundaries with model fields from the same global simulation. The atmospheric forcing is based on the three-hourly winds, thermal forcing and precipitation forecast fields from the European Centre for Medium-Range Weather Forecasts [31], with spatial resolution of 0.125° (see below). The ECMWF provides daily global forecasts at 0:00 and 12:00 UTC with 0.125° resolution. Recent model upgrades have improved the overall performance of the forecasting system throughout the medium range. Further details on model description and verification can be found e.g., in the works of Ehard et al. [32] and Haiden et al. [33], and at ECM [31]. Here, ECMWF daily forecast products were used as atmospheric upper boundary conditions for the GoM-HYCOM 1/50 as well as for providing air temperature and wind drag for the OpenOil simulations with a 3 hourly time step.
The model assimilates satellite observations of Sea Surface Temperature and Sea Surface Height, and in situ observations of temperature and salinity from buoys, cruises, surface drifters, Argo floats and XBT casts. More details about the model configuration can be found in [16,24,30]. We used a detailed treatment of plume dynamics in HYCOM, based on Schiller and Kourafalou [10] that builds on a widely used parameterization that includes both salinity and momentum fluxes, pioneered by Kourafalou et al. [9]. A recent publication by Androulidakis et al. [16] shows the realism of the simulation employed here, with excellent agreement between modeled plume spreading and in situ data.
Two periods were studied here: 20–27 May 2010 and 2–10 July 2010. For the present study, altogether four simulations were performed, two for each period studied: one with the attributes mentioned above, called Reference simulation, and one called no river, in which the salinity fronts have been removed by shutting off the river discharge, setting precipitation to zero, and turning off the assimilation of salinity profiles. This is a procedure called "twin experiments" and is also used by other authors studying the effects of river fronts near large river outflows [34]. All other forcing conditions (e.g., meteorological and boundary) remained the same between the two experiments in order to investigate the impact of an individual forcing mechanism (here, the Mississippi buoyant discharge and the related density fronts) on the circulation features and furthermore on the oil spill extensions during the DwH period.
Wave properties were downloaded from the ECMWF third generation spectral WAve Model (WAM) global operational runs [35]. WAM is well known (see, e.g., [33,36]). The WAM model computes two-dimensional wave distribution, with 25 frequencies and 24 directions. The operational daily WAM forecasts used here are forced by the ECMWF atmospheric forecasts. WAM model output with 0.125° horizontal resolution was downloaded with 12-hourly time step and used here for estimating horizontal Stokes drift and vertical mixing of the oil with a three-hourly time step using linear interpolation.
From the two-dimensional wave spectra, the surface Stokes drift, significant wave height, and mean wave period were computed and used in the oil drift model for the calculation of wave-induced transport and mixing. For the wave-induced transport, a vertical Stokes drift profile is computed based on surface Stokes drift, significant wave height and mean wave period according to Breivik et al. [37].
According to the simulated wind conditions derived by the ECMWF, wind speed varied between 0.1 and 7.2 ms−1 and the significant wave height varied between 0.1 and 1.2 m during the first period. In the second period, the corresponding values were 5–12 ms−1 and 0.1–3.2 m. The various forcing data are summerized in Table 1.
2.3. The Oil Drift Model OpenOil
OpenOil is part of the the OpenDrift trajectory modeling framework [26], developed at the Norwegian Meteorological Institute and available as open source software from [38]. OpenOil has been evaluated against drifter and oil slick observations in the North Sea [39,40]. A similar wind drift factor is used in other oil spill trajectory modeling in GoM [41]. Details of the element tracking model are given in Dagestad et al. [26], and model physics that are specific to oil transport and fate are documented in Röhrs et al. [40] and in the following.
OpenOil is an integrated oil drift model consisting of sub-models for specific physical processes such as wave entrainment of oil [42], vertical mixing due to oceanic turbulence and waves [40,43], resurfacing of oil due to buoyancy [44], and emulsification taking account for oil properties [45]. The resurfacing is a function of oil density and droplet size following Stokes Law, and thereby the model physics are very sensitive to the specification of the oil's droplet size. Figure 2 shows the sequence of operations involved in the OpenOil simulations.
2.3.1. Oil Droplet Size Distribution
Several algorithms are implemented to describe the oil's droplet size distribution, based on previous published parameterizations. The first option is based on the work of Delvigne and Sweeney [46] (DS88), manifesting a power-law droplet size number distribution as a function of droplet size, with an exponent of −2.3, i.e., there are many more small droplets than large droplets. Transferring this to a volume size distribution, as needed for practical oil spill simulation that follows the mass of the oil spill, the exponent becomes 0.7, i.e., there is more volume in the few large droplets than in the many small droplets. The typical droplet sizes range from 1 μm to 1 mm.
A second option to describe the droplet size distribution is based on Li et al. [47] (Li17), which takes the oil viscosity and the oil–water interfacial tension into account. This parameterization describes a log-normal law for the number size distribution, and the resulting volume size distribution exhibits a peak at an intermediate droplet size of about 100 μm, depending on oil type and environmental conditions. Similar types of droplet size distribution have been developed and observed, confirming that there is a maximum in oil volume at a particular droplet size [48,49].
Following Li et al. [47], the volume (V) droplet size spectrum is described by the median droplet diameter, D 50 V , as
D 50 V = d o r 1 + 10 Oh p · We q
with the empirical coefficient r = 1.791 and the exponents p = 0.460 and q = − 0.518 . The PDF for the droplet size distribution follows a log-normal distribution around the medium diameter with a logarithmic base-10 standard deviation of s = 0.38 (Equation 16 in Röhrs et al. [40]).
The Weber number, We , is a dimensionless number describing the relative importance of inertial forces and oil–water interfacial tension. It is a function of the sea water density, ρ w , the significant wave height, H s , and the oil–water interfacial tension, σ o − w , and is given by
We = ρ w g H s d o σ o − w ,
where g is the acceleration of gravity and d o = 4 σ o − w g ( ρ w − ρ o ) is the Rayleigh–Taylor instability maximum diameter.
The Ohnesorge number, Oh , is a dimensionless number describing the ratio of viscous forces to inertial and surface tension forces. It is a function of the dynamic oil viscosity, μ o , oil density, ρ o , and oil–water interfacial tension:
Oh = μ o ( ρ o σ o − w d o ) .
The volume size distribution, following Delvigne and Sweeney [46], is given by
V ( d ) = d − 0.7 , d m i n < d < d m a x
where d is the droplet diameter. Minimum and maximum droplet radii are set to 10−6 and 10−3 m, respectively. The exponent of − 0.7 in the volume size distribution corresponds to an exponent in the number size distribution of 2.3 [44].
Droplet sizes are assigned to oil particles each time an element is submerged by breaking waves, following the wave entrainment algorithm of Li et al. [42]. The implementation of this algorithm in OpenOil is described with full detail in [40]. The droplet sizes for individual particles are drawn from a random distribution according to the chosen size distribution. The size distributions represent conditions for a stochastic wave entrainment event, representing equilibrium conditions during a model time step. It is noted that the overall size distribution of all submerged oil in the simulation is further subject to changes, as weather conditions, the oil's emulsification rate change and oil droplets of various sizes are subjected to various resurfacing time scales. Resurfaced elements are considered to be part of a surface slick, and are assigned a new droplet size distribution once they are re-entrained. Oil droplets at the sea surface (slick) are not considered to have a radius.
2.3.2. Droplet Size Distribution During Deep Blowouts
For oil elements released at the seafloor (wellhead), a simplistic and pragmatic approach of prescribing random radii in the range 0.5–5 mm is used, as suggested by Johansen [50].
2.3.3. Horizontal Transport
With regard to horizontal drift, three processes are considered: Any element, whether submerged or at the surface, drifts along with the ocean current. Elements are further subject to Stokes drift corresponding to their actual depth. Surface Stokes drift is normally obtained from a wave model, and its decline with depth is calculated as described in Breivik et al. [37]. Oil elements at the ocean surface are additionally moved with a factor of 2% of the wind. Together with the Stokes drift (typically 1.5% of the wind at the surface), which sums up to the commonly found empirical value of 3.5% of the wind speed [51]. The magnitude of the wind drift factor was discussed by Jones et al. [39] who stated that a 2% wind drift factor is required in OpenOil to reproduce their observations of a SOP in the North Sea. In essence, this is believed to be a compensation factor for the inability of any ocean model to represent the strong shear current in the upper few centimeters/decimeters of the ocean, and not surface oil actually moving relative to the water. It was found to be important in bringing the oil to the northern Gulf beaches [52,53].
The three horizontal drift components (currents, Stokes drift and wind drift) may lead to a very strong gradient of drift magnitude and direction in the upper few meters of the ocean. For this reason, it is also of critical importance to have a good description of the vertical oil transport processes.
2.3.4. Vertical Transport
Oil elements at the surface, regarded as being in the state of an oil slick, may be entrained into the ocean by breaking waves. The entrainment of oil droplets depends on both the wind and wave (breaking) conditions, but also on the oil properties, such as viscosity, density and oil–water interfacial tension. The buoyancy of droplets is calculated according to empirical relationships and the Stokes law following Tkalich and Chan [44], dependent on ocean stratification based on temperature and salinity from the ocean model, and the viscosities and densities of oil and water.
In addition to the wave induced entrainment, the oil elements are also subjected to vertical turbulence throughout the water column, described using a random-walk scheme based on the turbulent eddy diffusivity wind speed parameterization from Sundby [54].
2.3.5. Weathering
To calculate weathering of the oil, OpenOil interfaces with the open source ADIOS oil library [55], developed by NOAA and Lehr et al. [45]. In addition to state-of-the-art parametrization of weathering processes such as evaporation, emulsification and dispersion, this software contains a database of measured properties of almost 1000 oil types from around the world. As oils from different sources or wells have vastly different properties, such a database is of vital importance for accurate results. The ADIOS oil library is also used by the NOAA oil drift model [56].
The weathering algorithms describes evaporation and emulsification rate of oil, i.e., the water content. The emulsification and evaporation greatly affect oil density, viscosity and oil–water interfacial tension, and thereby the droplet size distribution through Equations (1)–(3). OpenOil takes into consideration weathering processes that are dominating in the initial oil spill period of 2–3 days. Long-term weathering processes such as sedimentation and microbial degradation are not considered in this study.
A first set of simulations was carried out to investigate the effect of oil droplet size distribution. A second set focuses on the effect of river induced fronts. According to Crone and Tolstoy [6], the average flow rate from the oil well between 22 April and 3 June 2010 was estimated to 0.1 m3 s−1, assuming a liquid oil fraction of 0.4. Gas and highly volatile compounds are not considered here. After the riser was removed and until the leak was sealed on 15 July, the flow rate increased to 0.12 m3 s−1, corresponding to 10,368 m3 day−1. The amount of oil present at the sea surface at the initial time of the simulation was estimated based on the simulated removal rate, following the pioneering work of Liu et al. [22] and Liu et al. [23]. The residence time of oil at the sea surface depends heavily on oil properties as well as environmental conditions such as temperature of ocean and air, wind and waves, as described above. According to our mass balance calculations for the DWH spill, using the Light Louisiana Sweet oil type from the NOAA oil library and environmental conditions as described above, it seems reasonable to assume that 80% of the oil mass is removed from the surface after 10 days. This is within the range in our simulations that is typically 60–95% (see examples of mass balance plots further down). While Boufadel et al. [57] assumed a constant removal rate of surface oil 20% per day, the removal rate in the present simulation and in reality will vary with wind and wave conditions. The simulations for May 2010 were initialized by seeding 48,730 elements in a polygon obtained from NOAA shapefiles. Each element represents initially 1 m3 oil. A continuous point source at the sea floor seeds an additional 8460 elements (8460 m−3) per day during the simulation. After 3 June, these numbers were increased by 20% to 10,368 m3 day−1. The oil elements released at the surface were assigned droplet radii at each entrainment incident, according to the parameterization of size distributions from respectively DS88 or Li17 (see [40] for details). Oil elements at the sea surface (slick) were not considered to have a radius.
Around 20–25 May 2010, there was a significant outflow of the Mississippi River (Figure 3) and part of the SOP was entrained along the LC resulting in a formation popularly referred to as the "tiger tail" (Figure 4) [53]. The OpenOil simulation shown in Figure 4a was carried out using the classical DS88 oil droplet size distribution [46]. Figure 4b shows the results from repeating this simulation using the new Li17 formulation. In Figure 5, the mass balance during seven days for the Li17 simulation is shown. There is virtually no difference between DS88 and Li17 and only Li17 is shown here. Both formulations result in about the same fraction of oil at the surface (about 50%) after seven days, with moderate wind speeds of up to 7.2 ms−1. The light compounds evaporate fast after release, hence the more heavy compounds are tracked here ("dead oil"). Patches of thick oil (where the elements retain nearly 100% of their mass) are visible over a larger area (Figure 4). Larger oil droplets will rise more quickly to the surface [17,40], and DS88 provides a much higher fraction of large droplet after one hour compared to Li17 (Figure 6a,b). However, it turns out that the DS88 and Li17 provide similar volume distributions after a 24 h test simulation (Figure 6c,d). The peak in the distribution is still at around 100 μm for both formulations, and rapid rising to the surface can be expected according to North et al. [17]. Due to the small difference between DS88 and Li17, the DS88 simulation results in just marginally more oil stranded after seven days (13.2% vs. 12.8%), particularly west of the Mississippi Delta (Figure 4). A higher fraction of oil at the surface provides more efficient transport by wind and waves towards the shore and larger likelihood of stranding. For both simulations, the oil droplets quickly lose 40–50% of their mass, mostly through evaporation.
Figure 7 shows the geographical distribution of droplet diameters at the surface. It is apparent that smaller droplets are present outside the MAFLA shelf, probably because the oil droplets have been subjected to more wind and hence wave action and natural dispersion in the last 24 h (Figure 8).
The Li17 formulation was applied for two types of simulations: Reference (all forcing data) and no river (all forcing data except for river runoff and precipitation). Two periods were chosen for these experiments: a high river discharge period with variable winds (20–27 May) and a relatively lower discharge period with persistent westward winds (2–10 July). The purpose was to investigate the effect of the salinity fronts by using the ocean circulation from the no river simulation, in which the precipitation and river discharge were turned off, while atmospheric and wave forcing were kept the same. Figure 9, Figure 10, Figure 11 and Figure 12 show how the inclusion of river discharge in the ocean forcing can have opposite (and sometimes counter-intuitive) effects on oil transport. Table 2 summarizes the difference of the Reference and no river simulations for 20–27 May, while Table 3 shows corresponding values for the 2–10 July simulations.
Kourafalou and Androulidakis [3], based on high-resolution ocean simulations over the NGoM, showed that the MR discharge peak around 20–30 May led to the formation of downstream (westward) and upstream (northeastward) plume areas that acted as a conduit for guiding oil toward the LATEX shelf and away from the MAFLA shelf, respectively (Figure 10). In the 20–27 May period, the river plume currents created a strong "bulge" that tended to turn waters clockwise around the Delta, with some waters moving westward. Figure 10 shows that the drift patterns of the SOP as observed in NOAA satellite images are generally reproduced by the model. Figure 10 also shows how the SOP is guided by the river fronts that stretches relatively far south in GoM. In addition, the offshore GoM circulation (LC and eddies) removed the riverine waters offshore, toward the GoM interior, forming the so-called "tiger tail" pathway. The removal of the MR input in the no river experiment during this period (Figure 9) allowed the spreading of oil toward the western MAFLA shelf due to the absence of the anticyclonic bulge; the stranded oil along the MAFLA coasts is more apparent in the no river case in comparison to the Reference experiment. In contrast, the amount of stranded oil is less along the western coasts (90 W–91 W) in the no river experiment due to the absence of the downstream MR plume pathway (Table 1). Moreover, the "tiger tail" signature is weaker in the no river simulation. Herein, we confirm with oil spill simulations that the strength of this MR offshore jet could have been an important factor in forming the "tiger tail" oil distribution pattern as also shown from observational data [58] and ocean simulations [3].
The second study period (2–10 July) was right after another high discharge period (although not as high as in May, Figure 3), promoting again a buoyancy-driven downstream current. This tendency was supported by downwelling-favorable winds [3], resulting in a clear westward transport of both low-salinity and oil containing waters, along a narrow band (of similar width) close to the LATEX coast and surrounding the MR Delta; extensive coastal areas of stranded oil are apparent along the western coasts in the Reference experiment (Figure 11 and Figure 12). The removal of the river input (no river experiment) led to weaker downstream currents both close to the Delta (89.5° W) and along the western coasts (west of 90° W) and thus less stranded oil over the same region and more in the MR delta region (Table 3). The anticyclonic bulge, common in strong discharges and source of the downstream current [9], is completely absent in the no river experiment. As a result, more stranded oil was present closer to the Delta, inside the Louisiana Bight 3. It seems the absence of the anticyclonic bulge that was able to lead surface oiled waters directly west of the Louisiana Bight allowed the accumulation of oil very close to the Delta. In contrast, smaller differences between the two experiments were detected over the MAFLA region due to the weaker upstream currents during early July [3]. During this period of slightly higher wind speed, most elements appear to have lost 70–90% of their mass due to natural dispersion by waves and evaporation shortly after release (Figure 11).
Several simulations of the DWH oil spill were carried out with high resolution forcing data and a Lagrangian oil spill model. Simulations were initialized from satellite observations of the SOP, and a continuous point source with a realistic spill rate at the sea floor.
Our results indicate that the two different formulations for oil droplet size distribution give similar results for both vertical and horizontal distribution of the oil, when wind speeds are typically 5–12 ms−1 and breaking waves appear (Figure 4). Both formulations of the oil droplet size distribution result in the characteristic "tiger tail" shape of the SOP for the period 20–27 May 2010, and significant stranding in the delta west of the MR mouth in line with the observed SOP [3].
Both droplet size formulations that are used here (DS88 and Li17) result in similar size distributions after some time of simulation, as shown in Figure 6. Li17 prescribes a maximum droplet diameter in the volume distribution, as shown in Figure 6, which is due to two regimes in the size distribution where small droplets are limited by viscous effects, and larger droplets by oil–water interfacial tension [49]. This causes a peak in the volume distribution as seen in laboratory experiments with repeated mixing and wave breaking from the surface [49]. The DS88 distribution does not prescribe such a maximum, using a power-law that increases towards larger droplets in the volume distribution. However, the time-integrated simulations in OpenOil still produce a maximum in the droplet size distribution. The reason for this is the repeated wave breaking at the surface, which is more pertinent to large droplets that quickly rise to the surface. Hence, the description of buoyancy driven resurfacing and wave breaking in the oil spill model, together with the DS88 droplet size spectrum for individual wave breaking events, produces similar results to a more advanced droplet size distribution that explicitly prescribes a maximum in the volume size distribution. In conclusion, two very different droplet distributions give very similar distributions after some time. That indicates that the wave entrainment, vertical mixing and re-surfacing mechanisms that are part of OpenOil are more important for determining the final droplet size spectrum than the prescribed spectrum for individual wave breaking events.
A realistic description of droplet formation is required to describe the effects of an oil spill on the environment [17,40,57]. Figure 7 shows that the oil spill transport during the DWH spill favors a transport of small droplets towards the northeast, while larger oil droplets follow the paths towards southwest and southeast. As a result of their low buoyancy and turbulent mixing, smaller droplets are mixed into deeper parts of the ocean and subject to ocean currents at depth [40]. Larger droplets experience stronger buoyancy and are subject to surface currents while they may return to the surface slick. As wind and waves only affect the near-surface drift, the part of the oil slick that forms large droplets is quickly separated from the small droplets which retain at deep layers [17]. It was previously found that wave transport is important to bring oil the northern Gulf beaches [52]. The vertical mixing may also change the effect of the spill on the ecosystem: the parts of the oil spill at the surface is more hazardous to birds and the beach communities, while the small, submerged parts will have a substantially larger surface area to interact with water, fish and plankton [59,60].
The effect of realistic river discharge on the simulations was studied. One might expect that removing the river discharge would always bring the oil nearer to the shore, however interactions are complex. The no river simulation for 20–27 May showed more stranding oil, in particular close to the Louisiana Bight, but less stranding oil further downstream, along the LATEX shelf. The removal of the MR input reduced the downstream currents that were responsible for the westward transport of oiled waters along the LATEX shelf during the summer of 2010, as presented by Kourafalou and Androulidakis [3]. The MR plume and the accompanying river fronts were responsible to either entrap oil close to the coasts (e.g., LATEX shelf) or keep oiled waters offshore (e.g., MAFLA shelf) due to the formation of upstream currents (Figure 10). These results are in line with Kourafalou and Androulidakis [3] and the NOAA SOP observations used here and shown in Figure 9. It is also obvious that, in the Reference simulation, the oil elements are guided by the river fronts and they are carried further away from the coast, pushed into the LC south of 28° N and E of 88.5° W Figure 10.
The second simulation period (2–8 July) was right after a second high discharge period, promoting again a buoyancy-driven downstream current. This tendency is supported by downwelling-favorable winds, resulting in a clear westward transport of both low-salinity and oil-containing waters, along a narrow band close to the LATEX coast and surrounding the Mississippi Delta; extensive coastal areas of stranded oil are apparent along the western coasts in the Reference experiment. The removal of MR input (No River experiment) led to weaker downstream currents both close to the delta (89.5° W) and along the western coasts (west of 90° W) and thus less stranded oil over the same region.
The simulations presented here were initiated by seeding oil elements evenly in a polygon defined by NOAA satellite products [27], in addition to a continuous point source at the sea floor. The next possible step is to initiate the simulations from satellite products which contain information about oil film thickness in addition to area, and hence also quantify the amount of oil at the surface.
To the best of our knowledge, this is the first time that the importance of the effect of river fronts on oil slick transport in the Gulf of Mexico has been demonstrated using a fully fledged oil drift model nested on a high-resolution ocean model. Another new finding is that two very different oil droplet size distributions give similar net results compared to observed surface oil slicks. Future improvement of the OpenOil model could include implementation of horizontal dispersion by waves [61,62], but will be computationally demanding, and higher temporal resolution of the wave model output would be required. Bio-degradation is another factor important for longer simulations [21,63], which will be included in OpenOil in the near future.
Finally, as discussed by Liu et al. [23] and Liu et al. [53], human intervention activities to collect or remove the oil, for example, by use of dispersants, burning at sea, and skimming by boats, add uncertainties to the fate of the oil. This is not considered in the simulations presented here.
Formal analysis, L.R.H., Y.A. and M.L.H.; Funding acquisition, V.H.K.; Project administration, V.H.K.; Software, K.-F.D., J.R. and H.K.; Writing—original draft, L.R.H.; and Writing—review and editing, J.R., C.W., V.H.K., Y.A., M.L.H. and O.G.-P.
This research was made possible by a grant from The Gulf of Mexico Research Initiative (award "Influence of river induced fronts on hydrocarbon transport", GOMA 23160700).
Atmospheric and wave data were kindly provided by the European Center for Medium- Range Weather Forecasts (ECMWF). M. Le Hénaff acknowledges partial support from the Physical Oceanography Division at NOAA's Atlantic Oceanographic and Meteorological Laboratory, AOML. This research was made possible by a grant from The Gulf of Mexico Research Initiative, award GOMA23160700. Data are publicly available through the Gulf of Mexico Research Initiative Information & Data Cooperative (GRIIDC) at https://data.gulfresearchinitiative.org, (GRIIDC - doi: 10.7266/N7NG4NPG, 10.7266/n7-gh86-8p66, 10.7266/n7-mw7c-bw15, and 10.7266/n7-11g0-cq20).
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
The following abbreviations are used in this manuscript:
(N)GoM (Northern) Gulf of Mexico
DWH DeepWater Horizon
HYCOM HYbrid Coordinate Ocean Model
ECMWF European Center for Medium-Range Weather Forecasts
ADIOS Automated Data Inquiry for Oil Spills
MR Mississippi River
LC Loop Current
LATEX LouisianA TEXas shelf
MAFLA Mississippi Alabama FLoridA shelf
NOAA National Oceanic and Atmospheric Administration
USGS US Geological Survey
Joye, S.B.; Bracco, A.; Özgökmen, T.M.; Chanton, J.P.; Grosell, M.; MacDonald, I.R.; Cordes, E.E.; Montoya, J.P.; Passow, U. The Gulf of Mexico ecosystem, six years after the Macondo oil well blowout. Deep Sea Res. Part II Top. Stud. Oceanogr. 2016, 129, 4–19. [Google Scholar] [CrossRef]
Beyer, J.; Trannum, H.C.; Bakke, T.; Hodson, P.V.; Collier, T.K. Environmental effects of the Deepwater Horizon oil spill: A review. Mar. Pollut. Bull. 2016, 110, 28–51. [Google Scholar] [CrossRef] [PubMed]
Kourafalou, V.H.; Androulidakis, Y.S. Influence of Mississippi River induced circulation on the Deepwater Horizon oil spill transport. J. Geophys. Res. Ocean. 2013, 118, 3823–3842. [Google Scholar] [CrossRef]
Le Hénaff, M.; Kourafalou, V.H.; Paris, C.B.; Helgers, J.; Aman, Z.M.; Hogan, P.J.; Srinivasan, A. Surface evolution of the Deepwater Horizon oil spill patch: Combined effects of circulation and wind-induced drift. Environ. Sci. Technol. 2012, 46, 7267–7273. [Google Scholar] [CrossRef] [PubMed]
Gulf of Mexico Fact Sheet-U.S. Energy Information Administration. Available online: www.eia.gov/special/gulf_of_mexico/ (accessed on 26 June 2019).
Crone, T.J.; Tolstoy, M. Magnitude of the 2010 Gulf of Mexico oil leak. Science 2010, 330, 634. [Google Scholar] [CrossRef] [PubMed]
McNutt, M.K.; Camilli, R.; Guthrie, G.D.; Hsieh, P.A.; Labson, V.F.; Lehr, W.J.; Maclay, D.; Ratzel, A.C.; Sogge, M.K. Assessment of Flow Rate Estimates for the Deepwater Horizon/Macondo Well Oil Spill; US Department of the Interior: Washington, DC, USA, 2011. [Google Scholar]
Androulidakis, Y.; Kourafalou, V.; Özgökmen, T.; Garcia-Pineda, O.; Lund, B.; Le Hénaff, M.; Hu, C.; Haus, B.K.; Novelli, G.; Guigand, C.; et al. Influence of River-Induced Fronts on Hydrocarbon Transport: A Multiplatform Observational Study. J. Geophys. Res. Ocean. 2018. [Google Scholar] [CrossRef]
Kourafalou, V.H.; Lee, T.N.; Oey, L.Y.; Wang, J.D. The fate of river discharge on the continental shelf: 2. Transport of coastal low-salinity waters under realistic wind and tidal forcing. J. Geophys. Res. Ocean. 1996, 101, 3435–3455. [Google Scholar] [CrossRef]
Schiller, R.V.; Kourafalou, V.H. Modeling river plume dynamics with the HYbrid Coordinate Ocean Model. Ocean Model. 2010, 33, 101–117. [Google Scholar] [CrossRef]
Hickey, B.M.; Shillington, F.A.; Strub, P.; Brink, K.H.; Barton, E.D.; Thomas, A.C. Eastern ocean boundaries. Sea Reg. Stud. Synth. 1998, 11, 29. [Google Scholar]
Walker, N.D.; Huh, O.K.; Rouse, L.J.; Murray, S.P. Evolution and structure of a coastal squirt off the Mississippi River delta: Northern Gulf of Mexico. J. Geophys. Res. Ocean. 1996, 101, 20643–20655. [Google Scholar] [CrossRef]
Schiller, R.; Kourafalou, V.; Hogan, P.; Walker, N. The dynamics of the Mississippi River plume: Impact of topography, wind and offshore forcing on the fate of plume waters. J. Geophys. Res. Ocean. 2011, 116. [Google Scholar] [CrossRef]
Hu, C.; Nelson, J.R.; Johns, E.; Chen, Z.; Weisberg, R.H.; Müller-Karger, F.E. Mississippi River water in the Florida Straits and in the Gulf Stream off Georgia in summer 2004. Geophys. Res. Lett. 2005, 32. [Google Scholar] [CrossRef]
Schiller, R.; Kourafalou, V. Loop Current impact on the transport of Mississippi River waters. J. Coast. Res. 2014, 30, 1287–1306. [Google Scholar] [CrossRef]
Androulidakis, Y.; Kourafalou, V.; Le Hénaff, M.; Kang, H.; Sutton, T.; Chen, S.; Hu, C.; Ntaganou, N. Offshore spreading of Mississippi waters: pathways and vertical structure under eddy influence. J. Geophys. Res. Ocean. 2019. [Google Scholar] [CrossRef]
North, E.W.; Adams, E.E.; Schlag, Z.; Sherwood, C.R.; He, R.; Hyun, K.H.; Socolofsky, S.A. Simulating oil droplet dispersal from the Deepwater Horizon spill with a Lagrangian approach. Geophys. Monogr. Ser. 2011, 195, 217–226. [Google Scholar]
Mariano, A.J.; Kourafalou, V.H.; Srinivasan, A.; Kang, H.; Halliwell, G.; Ryan, E.; Roffer, M. On the modeling of the 2010 Gulf of Mexico oil spill. Dyn. Atmos. Ocean. 2011, 52, 322–340. [Google Scholar] [CrossRef]
MacFadyen, A.; Watabayashi, G.; Barker, C.; Beegle-Krause, C. Tactical modeling of surface oil transport during the Deepwater Horizon spill response. Monit. Model. Deep. Horiz. Oil Spil. 2011, 195, 167–178. [Google Scholar]
Barker, C. A statistical outlook for the Deepwater Horizon oil spill. Monit. Model. Deep. Horiz. Oil Spil. 2011, 195, 237–244. [Google Scholar]
Paris, C.B.; Hénaff, M.L.; Aman, Z.M.; Subramaniam, A.; Helgers, J.; Wang, D.P.; Kourafalou, V.H.; Srinivasan, A. Evolution of the Macondo well blowout: Simulating the effects of the circulation and synthetic dispersants on the subsea oil transport. Environ. Sci. Technol. 2012, 46, 13293–13302. [Google Scholar] [CrossRef]
Liu, Y.; Weisberg, R.H.; Hu, C.; Zheng, L. Trajectory forecast as a rapid response to the Deepwater Horizon oil spill. Monit. Model. Deep. Horiz. Oil Spil. 2011, 195, 153–165. [Google Scholar]
Liu, Y.; Weisberg, R.H.; Hu, C.; Zheng, L. Tracking the Deepwater Horizon oil spill: A modeling perspective. Eos Trans. Am. Geophys. Union 2011, 92, 45–46. [Google Scholar] [CrossRef]
Androulidakis, I.; Kourafalou, V.; Le Hénaff, M.; Kang, H.S.; Ntaganou, N. Loop Current evolution during the Deepwater Horizon oil spill period: The role of mesoscale dynamics over Northwestern Cuba. Submitt. J. Mar. Syst. 2018. [Google Scholar]
Li, Z.; Johnson, W. An Improved Method to Estimate the Probability of Oil Spill Contact to Environmental Resources in the Gulf of Mexico. J. Mar. Sci. Eng. 2019, 7, 41. [Google Scholar] [CrossRef]
Dagestad, K.F.; Röhrs, J.; Breivik, Ø.; Ådlandsvik, B. OpenDrift v1. 0: A generic framework for trajectory modelling. Geosci. Model Dev. 2018, 11, 1405–1420. [Google Scholar] [CrossRef]
NOAA-Environmental Response Management Application (ERMA). Available online: https://erma.noaa.gov/gulfofmexico/erma.html#/layers=1+35410+10717+9816+16973+13763+38385+28055&x=-88.09771&y=28.81982&z=8&panel=layer (accessed on 26 June 2019).
Hybrid Coordinate Ocean Model. Available online: www.hycom.org (accessed on 30 May 2019).
Bleck, R. An oceanic general circulation model framed in hybrid isopycnic-Cartesian coordinates. Ocean Model. 2002, 4, 55–88. [Google Scholar] [CrossRef]
Le Hénaff, M.; Kourafalou, V.H. Mississippi waters reaching South Florida reefs under no flood conditions: Synthesis of observing and modeling system findings. Ocean Dyn. 2016, 66, 435–459. [Google Scholar] [CrossRef]
European Centre for Medium-Range Weather Forecasts. Available online: https://www.ecmwf.int/en/forecasts/accessing-forecasts (accessed on 26 June 2019).
Ehard, B.; Malardel, S.; Dörnbrack, A.; Kaifler, B.; Kaifler, N.; Wedi, N. Comparing ECMWF high resolution analyses to lidar temperature measurements in the middle atmosphere. Q. J. R. Meteorol. Soc. 2016, 144, 633–640. [Google Scholar] [CrossRef]
Haiden, T.; Janousek, M.; Bidlot, J.; Ferranti, L.; Prates, F.; Vitart, F.; Bauer, P.; Richardson, D. Evaluation of ECMWF Forecasts, Including the 2016 Resolution Upgrade; European Centre for Medium Range Weather Forecasts: Reading, UK, 2016. [Google Scholar]
Luo, H.; Bracco, A.; Cardona, Y.; McWilliams, J.C. Submesoscale circulation in the northern Gulf of Mexico: Surface processes and the impact of the freshwater river input. Ocean Model. 2016, 101, 68–82. [Google Scholar] [CrossRef]
ECMWF Wave Forecasts. Available online: http://apps.ecmwf.int/mars-catalogue/?class=od&stream=wave (accessed on 30 May 2019).
Group, T.W. The WAM model—A third generation ocean wave prediction model. J. Phys. Oceanogr. 1988, 18, 1775–1810. [Google Scholar] [CrossRef]
Breivik, Ø.; Bidlot, J.R.; Janssen, P.A. A Stokes drift approximation based on the Phillips spectrum. Ocean Model. 2016, 100, 49–56. [Google Scholar] [CrossRef]
OpenDrift-Open Source Framework for Ocean Trajectory Modelling. Available online: www.github.com/opendrift (accessed on 26 June 2019).
Jones, C.E.; Dagestad, K.F.; Breivik, Ø.; Holt, B.; Röhrs, J.; Christensen, K.H.; Espeseth, M.; Brekke, C.; Skrunes, S. Measurement and modeling of oil slick transport. J. Geophys. Res. Ocean. 2016, 121, 7759–7775. [Google Scholar] [CrossRef]
Röhrs, J.; Dagestad, K.F.; Asbjørnsen, H.; Nordam, T.; Skancke, J.; Jones, C.; Brekke, C. The effect of vertical mixing on the horizontal drift of oil spills. Ocean Sci. Discuss. 2018. [Google Scholar] [CrossRef]
Abascal, A.J.; Castanedo, S.; Minguez, R.; Medina, R.; Liu, Y.; Weisberg, R.H. Stochastic Lagrangian trajectory modeling of surface drifters deployed during the Deepwater Horizon oil spill. In Thirty-Eighth AMOP Technical Seminar; Environment Canada: Ottawa, ON, Canada, 2015; pp. 77–91. [Google Scholar]
Li, Z.; Spaulding, M.L.; French-McCay, D. An algorithm for modeling entrainment and naturally and chemically dispersed oil droplet size distribution under surface breaking wave conditions. Mar. Pollut. Bull. 2017, 119, 145–152. [Google Scholar] [CrossRef]
Nordam, T.; Kristiansen, R.; Nepstad, R.; Röhrs, J. Numerical analysis of boundary conditions in a Lagrangian particle model for vertical mixing, transport and surfacing of buoyant particles in the water column. Ocean Model. 2019, 136, 107–119. [Google Scholar] [CrossRef]
Tkalich, P.; Chan, E.S. Vertical mixing of oil droplets by breaking waves. Mar. Pollut. Bull. 2002, 44, 1219–1229. [Google Scholar] [CrossRef]
Lehr, W.; Jones, R.; Evans, M.; Simecek-Beatty, D.; Overstreet, R. Revisions of the ADIOS oil spill model. Environ. Model. Softw. 2002, 17, 189–197. [Google Scholar] [CrossRef]
Delvigne, G.A.L.; Sweeney, C. Natural dispersion of oil. Oil Chem. Pollut. 1988, 4, 281–310. [Google Scholar] [CrossRef]
Li, Z.; Spaulding, M.; McCay, D.F.; Crowley, D.; Payne, J.R. Development of a unified oil droplet size distribution model with application to surface breaking waves and subsea blowout releases considering dispersant effects. Mar. Pollut. Bull. 2017, 114, 247–257. [Google Scholar] [CrossRef]
Johansen, Ø.; Reed, M.; Bodsberg, N.R. Natural dispersion revisited. Mar. Pollut. Bull. 2015, 93, 20–26. [Google Scholar] [CrossRef]
Li, C.; Miller, J.; Wang, J.; Koley, S.S.; Katz, J. Size Distribution and Dispersion of Droplets Generated by Impingement of Breaking Waves on Oil Slicks. J. Geophys. Res. Ocean. 2017, 122, 7938–7957. [Google Scholar] [CrossRef]
Johansen, Ø. DeepBlow—A Lagrangian plume model for deep water blowouts. Spill Sci. Technol. Bull. 2000, 6, 103–111. [Google Scholar] [CrossRef]
Schwartzberg, H.G. The movement of oil spills. In International Oil Spill Conference; American Petroleum Institute: Washington, DC, USA, 1971; pp. 489–494. [Google Scholar]
Weisberg, R.H.; Lianyuan, Z.; Liu, Y. On the movement of Deepwater Horizon Oil to northern Gulf beaches. Ocean Model. 2017, 111, 81–97. [Google Scholar] [CrossRef]
Liu, Y.; MacFadyen, A.; Ji, Z.G.; Weisberg, R.H. Monitoring and Modeling the Deepwater Horizon Oil Spill: A Record Breaking Enterprise; John Wiley & Sons: Hoboken, NJ, USA, 2011; Volume 195. [Google Scholar]
Sundby, S. A one-dimensional model for the vertical distribution of pelagic fish eggs in the mixed layer. Deep Sea Res. Part A. Oceanogr. Res. Papers 1983, 30, 645–661. [Google Scholar] [CrossRef]
NOAA-Oil Library. Available online: github.com/NOAA-ORR-ERD/OilLibrary (accessed on 26 June 2019).
NOAA-Oil Drift Model. Available online: github.com/NOAA-ORR-ERD/PyGnome (accessed on 26 June 2019).
Boufadel, M.C.; Abdollahi-Nasab, A.; Geng, X.; Galt, J.; Torlapati, J. Simulation of the landfall of the deepwater horizon oil on the shorelines of the Gulf of Mexico. Environ. Sci. Technol. 2014, 48, 9496–9505. [Google Scholar] [CrossRef]
Walker, N.D.; Pilley, C.T.; Raghunathan, V.V.; D'Sa, E.J.; Leben, R.R.; Hoffmann, N.G.; Brickley, P.J.; Coholan, P.D.; Sharma, N.; Graber, H.C.; et al. Impacts of Loop Current frontal cyclonic eddies and wind forcing on the 2010 Gulf of Mexico oil spill. Monit. Model. Deep. Horiz. Oil Spil. 2011, 195, 103–116. [Google Scholar]
Short, J.W. Advances in understanding the fate and effects of oil from accidental spills in the United States beginning with the Exxon Valdez. Arch. Environ. Contam. Toxicol. 2017, 73, 5–11. [Google Scholar] [CrossRef]
Carroll, J.; Vikebø, F.; Howell, D.; Broch, O.J.; Nepstad, R.; Augustine, S.; Skeie, G.M.; Bast, R.; Juselius, J. Assessing impacts of simulated oil spills on the Northeast Arctic cod fishery. Mar. Pollut. Bull. 2018, 126, 63–73. [Google Scholar] [CrossRef]
Giarrusso, C.; Carratelli, E.P.; Spulsi, G. On the effects of wave drift on the dispersion of floating pollutants. Ocean Eng. 2001, 28, 1339–1348. [Google Scholar] [CrossRef]
Caratelli, E.; Dentale, F.; Reale, F. On the effects of wave-induced drift and dispersion in the Deepwater Horizon oil spill. Monit. Model. Deep. Horiz. Oil Spil. 2011, 195, 197–204. [Google Scholar]
Adcroft, A.; Hallberg, R.; Dunne, J.P.; Samuels, B.L.; Galt, J.A.; Barker, C.H.; Payton, D. Simulations of underwater plumes of dissolved oil in the Gulf of Mexico. Geophys. Res. Lett. 2010, 37. [Google Scholar] [CrossRef]
Figure 1. Map of the Northern Gulf of Mexico showing the geographical locations mentioned in the text. The map insert shows the Mississippi River (MR) delta in blue with the three major river passes that release MR water into the Gulf.
Figure 2. Flow chart showing the sequence of operations involved in the OpenOil simulations.
Figure 3. Discharge from Mississippi River in the Northern Gulf of Mexico during late spring and early summer 2010. Data kindly provided by U.S. Army Corps of Engineers.
Figure 4. OpenOil simulation for 20–27 May 2010, using the Delvigne and Sweeney [46] oil droplet size distribution (a, 13.2% stranded oil), and the Li et al. [42] distribution (b, 12.8% stranded oil). Only surface oil elements are shown. Patch colors are the fraction of mass left in the elements. Magenta areas indicate stranded oil.
Figure 5. Mass balance of oil in the OpenOil simulation shown in Figure 2. The Li et al. [42] oil droplet size distribution is used.
Figure 6. Oil droplet volume histogram for 1000 elements after 1 h using the Light Louisiana Sweet, BP oil type in OpenOil during 8 ms − 1 wind. The initial condition is a uniform distribution. Delvigne and Sweeney [46] (a) and Li et al. [42] (b). Bottom panels show corresponding distributions after 24 h.
Figure 7. End condition of the Reference simulation 20–27 May 2010, showing all active elements (at surface and submerged). Same simulation as in Figure 4b. Stranded oil is shown in magenta. The color scale shows diameter of the oil droplets.
Figure 8. Same as Figure 7, but the color scale shows the average wind speed experienced by the element during the last 12 h.
Figure 9. End condition of the simulation 20–27 May 2010, showing active (at surface) and stranded oil elements. Stranded oil is shown in magenta. The color scale indicate how much mass is left in each element. Red arrows are the GoM-HYCOM 1/50 forcing surface currents at the last time step of the simulation (every 5th data point shown). Reference simulation in (a) (12.1% stranded oil), and no river simulation shown in (b) (6% stranded oil) (see also Table 2).
Figure 10. End condition of the Reference simulation 20–27 May 2010 same simulation as in Figure 9a, showing active elements at surface as red dots and the corresponding observed surface oil patch (NOAA shape file) as black dots. Modeled stranded oil is shown in magenta. The color scale shows sea surface salinity in the forcing data. The black contour is the 35 PSU isoline.
Figure 11. End condition of the simulation 2–10 July 2010, showing active (at surface) and stranded oil elements. Stranded oil is shown in magenta. The color scale indicate how much mass is left in each element. Red arrows are the GoM-HYCOM 1/50 surface currents at the last time step of the simulation (every 2nd data point shown). Reference simulation in (a) (48.1% stranded oil), and no river simulation in (b) (55.1% stranded oil) (see also Table 3).
Figure 12. End condition of the Reference simulation 2–10 July 2010 (same simulation as in Figure 11b), showing active elements at surface as red dots and the corresponding observed surface oil patch (NOAA shape file) as black dots. Stranded oil is shown in magenta. The color scale shows sea surface salinity in the forcing data. The black contour is the 35 PSU isoline.
Table 1. Summary of Metocean forcing used in the simulation.
Model Parameters Horizontal Vertical Temporal
NOAA shape files initial location
GOM Hycom horizontal current 1/50° 32 layers 3 h
ECMWF atmospheric model wind velocity, air temperature 1/8° surface 3 h
ECMWF wave model Stokes drift, wave height and period 1/8° surface 12 h
Table 2. Percentages of stranded oil elements for the May 20–27 simulations.
Reference Simulation
no river Simulation
West of MR Delta 6.9 0.5
MR Delta area 4.0 3.4
East of MR Delta 1.2 2.1
Total 12.1 6.0
Table 3. Percentages of stranded oil elements for the July 2–10 simulations.
West of MR Delta 10.6 7.8
MR Delta area 16.7 27.2
East of MR Delta 20.8 20.1
Total 48.1 55.1
J. Mar. Sci. Eng., EISSN 2077-1312, Published by MDPI AG

redpajama_set_name: RedPajamaCommonCrawl


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