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Kia Ora. Could you please give me some feedback on this essay :) Tena Koe
English level 2 2.1 Analyse specified aspect(s) of studied written
Cushlabridges 30 November 2021 04:13 #1
Question: Analyse how a relationship revealed strengths or weaknesses in a character
When isolated away from civilization, humans often revert to atypical behaviour and develop a mob mentality. This is shown in William Golding's adventure story "Lord of the Flies", through the relationship between two major characters, Ralph and Piggy. Ralph is the leader of the group, who makes many decisions but is seen as the plot develops, losing his power. Piggy is a disadvantaged character, who shows values such as honesty, integrity and loyalty. The relationship between these contrasting characters is explored through the use of language techniques such as punctuation and descriptive language, and as William Golding develops this core relationship it reveals weaknesses in Ralphs character such as how unloyal and praise seeking he is.
Ralph and Piggys friendship begins when they find themselves stranded on a deserted island together. Without any certainty that other boys are alive, they are under the assumption that they only have each other, (at least for now) so therefore, they must get along. In the early stages of their relationship, Piggy exposes his vulnerable side and is later seen getting betrayed by Ralph.
"His names are piggy, it's piggy like a pig hahaha!!!"-Ralph. This is the first instance in which Ralph shows that he has the weakness of being unloyal. He was aware that piggy did not want his nickname to be known, yet betrayed him as a way to get praise from the fellow islanders. His ignorance of the damage that he had done to Piggy and his emotions is shown in this quote through the use of repetition. Ralph repeats telling the boys it is 'Piggy' twice. This shows that he simply did not let it slip, but intentionally hurt his friend, and wanted the praise over his friendship.
This is seen in many situations in our society when leaders make speeches and repeat something over and over again; such as Martin Luther Kings speech 'I have a dream. Throughout his speech, he repeats the word I have a dream and is what people remember him for. They know that he has a dream and has no regrets for what he says in his speech, just like Ralph has no regrets in exposing piggy and backstabbing him. He shows a weakness of being unloyal through the abuse of Piggy and Ralphs relationship.
Another example from the text where Piggy and Ralphs relationship reveals Ralphs weak trait of being unloyal and praise seeking is when Ralph steals Piggies glasses unconventionally. In chapter 2 Ralph is described as, snatching piggies glasses and not returning them despite Piggies upset tone and begging. "Hey, give me back my glasses, GIVE THEM BACK… please" -Piggy screeching.
The use of descriptive language in this quote shows how truly upset Piggy is, and how also uncaring Ralph is. The fact that Piggy has to repeat his words twice and even add the word "please," tells the reader that Ralph was not giving his glasses back. William golding through the use of these language features tells the reader how Ralph does not care for Piggy and just utilises him as a tool for attention. Piggy relationship with Ralph is a way that he can get attention from the rest of the group.
Piggy and Ralphs relationship is similar to many relationships we see around us in everyday life. The friends who use each other for gossip at high school, the person who uses someone in a higher up status to make connections and get jobs, and a boss who puts down all their employers to make them seem better, and therefore get promoted. Piggy and Ralphs relationship is just a stereotypical example of a parasitic relationship that one person benefits from, and the other blindly doesn't. Their relationship shows how Ralph knowingly puts down someone who trusts him and steps on them to get ahead. This abuse of their relationship and loyalty to the trust Piggy has for Ralph, is a weakness in Ralph.
The final example from the text that highlights the weakness of loyalty and praise seeking within Ralph, through the relationship between him and Piggy is during the separation of the group. Throughout the development of the plot of this adventure novel, the power that Ralph has, is seen being diminished, and his rival Jack is seen gaining more and more power. Near the end of this novel, the group of boys split into two groups. All of the boys side with Jack, and Piggy is the only boy on the island that sides with Ralph and remains on his team. "I will stay with a jack I guess"-Piggy.
The use of language techniques in this quote tells the reader a lot about not only how Piggy is feeling, but also Ralphs Weak Qualities. The use of the descriptive language 'i guess', tells the reader that piggy is not as confident in his relationship with Ralph. This is because he has begun to see how Ralph has been abusing him to gain power and recognition. Ralphs weakness has led to not only him being left by all of the members on the island, but also by the only person who stuck by him being unsure of their relationship. His weakness of being unloyal and praise seeking lead to no one praising him and his loyal followers no longer having faith.
Many people experience times like this, when they may spread gossip they heard about their friend to get in with a new crowd, but end up losing all of their friends anyway. This is a very similar situation to Ralph. When left away from civilization, ralph resorted back to atypical survival behaviour and developed a mob mentality, forgetting about how to act like english. This weakness is shown through his relationship with Piggy.
William Golding throughout the novel 'Lord of the Flies' developed the relationship between Piggy and Ralph to highlight the weakness of unloyalty and praise seeking within Ralph. This relationship shows through the character of Ralph that when isolated, away from civilization and normalities, humans revert to atypical behaviour, and develop a mob mentality. Ralph reverted to attention-seeking behaviour, etching to get approval from his group, whilst being unloyal to his friendship.
nkilbride 30 November 2021 05:16 #2
Kia ora again!
Very clear and detailed intro.
Good reframe of the same details for a different question for the most part. One part of the question that could have used a little more exploring is the "weakness" of Ralph - this could have been more insightful if you dug a bit more into the way that he is creating strength for himself on the island, through something that us in "civilization' would consider a character weakness, because of the things we value. You get to why this character trait is a weakness well in your third paragraph, but it would have been good to analyse WHY it is a weakness a little earlier than that as well.
Solid conclusion


S134. Wakizashi in shira-saya, signed Hakushu Ju Ohara Sanemori.
Nagasa: 20 3/4" 52.6 cm.
Overall in shira-saya: 29 5/8" 75 cm.
Itame and mokume hada with chikei. The hamon is gunome in nioi with ko-nei as sunagashi cutting through the peaks of the hamon and joining across the valleys as kin suji. In the mono-uchi there are isolated spots of temper at the tops of the peaks. The boshi (devilishly difficult to photograph) undulates, ends in o-maru, and there is a medium length kaeri. There is one instance of a small tate-ware' a third of the way up the blade (my last picture is the best I can show of this) and a tiny spot just above the machi, both on the ura side. The blade is in polish and is mounted with a quite nice 2 piece habaki in gold and silver foil. There is one are of shallow denting on the shira-saya, which is otherwise in excellent condition and competently made (looks to be Japanese work). This will come with a 3 page record sheet, which I believe the former owner received from the merchant he bought it from.
The Ohara School got its start very early in Nihonto and lasted till the end of Koto. Best I can tell, this Sanemori worked in the early 16th century. Nice sword; I think you'll be pleased. 1 pound, 12 ounces. $980.


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The month that was: 'The Bridge' chronicles Brooklyn Nets December
By Net Income Jan 4, 2023, 7:12pm EST
Share All sharing options for: The month that was: 'The Bridge' chronicles Brooklyn Nets December
Photo by Mark Blinch/Getty Images
The video starts with a close-up view of the timeout at the end of the Raptors game when Kevin Durant suggests to Jacque Vaughn that Kyrie Irving might be a better choice for the buzzer beater needed for the win.
"Yo, Yo, you should run that for Kyrie," Durant told Vaughn and rest was history...
That's just part of the latest episode of "The Bridge," the Nets all-access video magazine, which focuses on the Nets month of December, the best month in franchise history. It includes a lot of insider views of the locker room, practices and huddles. And for Yuta Watanabe fans (who isn't?), there's a lot on his development in the video.

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Silicone Flow Blood is mouth safe and washable but has extra flow properties.
It will run like real blood and not bead on silicone props/appliances and direct applied effects.
Silicone Flow Blood is Sorbitol based and was developed to flow naturally on silicone props. It is very free flowing on skin and smudges very thinly.


Adesina - Name Meaning, What does Adesina mean?
Adesina as a girls' name is of Nigerian origin, and the meaning of Adesina is "my coming has opened the way". Often used to mark a birth if a couple has had difficulty conceiving, implying that this will be the first of many children.
Recommended sound-alike names are Adalina, Adamina, Addeson, Adeana, Adeena, Adelia▼, Adelina▲, Adelind, Adelinda, Adeline▲, Adelisa, Adelita, Adeliza, Adelyna, Ademina, Adena, Adina, Adison▼, Adrina, Adyson▼, Aegina, Alesia▼, Alexina, Alsina, Amelina, Aretina, Asemina, Avelina and Odelina. These names tend to be more commonly used than Adesina.


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Q: Why does this keep triggering multiple alerts? I'm trying to animate something, and I have this bit of code here:
Enemy.prototype.update = function () {
    var tx = 650 - this.x;
    var ty = 250 - this.y;
    var dist = Math.sqrt(tx * tx + ty * ty);
    this.velx = (tx / dist)* this.speed;
    this.vely = (ty / dist)* this.speed;
    var distround = Math.floor(dist);
    if (distround > 0) {
        this.x += this.velx;
        this.y += this.vely;
    } else if (this.transparency != 0){
      alert("You lose!");
      location.reload(true);
    }
};

I thought if I had the page refresh after the alert, it'd be okay, but sometimes there are a ton of alert boxes that pop up before it refreshes...how do I stop this? The full code is here: (warning, multiple alerts will be triggered...best not to use safari to open)
http://jsfiddle.net/nLxLpvry/

A: This is because every enemy has an update method that calls the alert. So when all the enemies disappear all the enemies call their alert which results in many many alert messages being displayed.

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Computers Horsham - Welcome to the Horsham Computers Directory from Tipped.co.uk featuring recommended computer stores in Horsham. It lists those who provide computers in Horsham. It also includes those who offer laptops in Horsham. Read reviews of Horsham laptops and write your own review too. If your Horsham computer business isn't listed, then advertise it for FREE today.


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Sea ice pCO2 dynamics and air–ice CO2 fluxes during the Sea Ice Mass Balance in the Antarctic (SIMBA) experiment – Bellingshausen Sea, Antarctica
N.-X. Geilfus et al.
Estimates of ikaite export from sea ice to the underlying seawater in a sea ice–seawater mesocosm
Nicolas-Xavier Geilfus, Ryan J. Galley, Brent G. T. Else, Karley Campbell, Tim Papakyriakou, Odile Crabeck, Marcos Lemes, Bruno Delille, and Søren Rysgaard
The fate of ikaite precipitation within sea ice is poorly understood. In this study, we estimated ikaite precipitation of up to 167 µmol kg-1 within sea ice, while its export and dissolution into the underlying seawater was responsible for a TA increase of 64–66 μmol kg-1. We estimated that more than half of the total ikaite precipitated was still contained in the ice when sea ice began to melt. The dissolution of the ikaite crystals in the water column kept the seawater pCO2 undersaturated.
Inorganic carbon dynamics of melt-pond-covered first-year sea ice in the Canadian Arctic
N.-X. Geilfus, R. J. Galley, O. Crabeck, T. Papakyriakou, J. Landy, J.-L. Tison, and S. Rysgaard
We investigated the evolution of inorganic carbon within landfast sea ice in Resolute Passage during the spring and summer melt period. Low TA and TCO2 concentrations observed in sea ice and brine were associated with the percolation of meltwater from melt ponds. Meltwater was continuously supplied to the ponds which prevented melt ponds from fully equilibrating with the atmospheric CO2 concentration, promoting a continuous uptake of CO2 from the atmosphere.
CO2 and CH4 in sea ice from a subarctic fjord under influence of riverine input
O. Crabeck, B. Delille, D. Thomas, N.-X. Geilfus, S. Rysgaard, and J.-L. Tison
Physical controls on the storage of methane in landfast sea ice
J. Zhou, J.-L. Tison, G. Carnat, N.-X. Geilfus, and B. Delille
Revisiting properties and concentrations of ice-nucleating particles in the sea surface microlayer and bulk seawater in the Canadian Arctic during summer
Victoria E. Irish, Sarah J. Hanna, Yu Xi, Matthew Boyer, Elena Polishchuk, Mohamed Ahmed, Jessie Chen, Jonathan P. D. Abbatt, Michel Gosselin, Rachel Chang, Lisa A. Miller, and Allan K. Bertram
Atmos. Chem. Phys., 19, 7775–7787, https://doi.org/10.5194/acp-19-7775-2019,https://doi.org/10.5194/acp-19-7775-2019, 2019
The ocean is a source of atmospheric ice-nucleating particles (INPs). In this study we compared INPs measured in microlayer and bulk seawater in the Canadian Arctic in 2016 to those measured in 2014. A strong negative correlation between salinity and freezing temperatures was observed, possibly due to INPs associated with melting sea ice. In addition, although spatial patterns of INPs and salinities were similar in 2014 and 2016, the concentrations of INPs were on average higher in 2016.
Overview paper: New insights into aerosol and climate in the Arctic
Jonathan P. D. Abbatt, W. Richard Leaitch, Amir A. Aliabadi, Allan K. Bertram, Jean-Pierre Blanchet, Aude Boivin-Rioux, Heiko Bozem, Julia Burkart, Rachel Y. W. Chang, Joannie Charette, Jai P. Chaubey, Robert J. Christensen, Ana Cirisan, Douglas B. Collins, Betty Croft, Joelle Dionne, Greg J. Evans, Christopher G. Fletcher, Martí Galí, Roghayeh Ghahremaninezhad, Eric Girard, Wanmin Gong, Michel Gosselin, Margaux Gourdal, Sarah J. Hanna, Hakase Hayashida, Andreas B. Herber, Sareh Hesaraki, Peter Hoor, Lin Huang, Rachel Hussherr, Victoria E. Irish, Setigui A. Keita, John K. Kodros, Franziska Köllner, Felicia Kolonjari, Daniel Kunkel, Luis A. Ladino, Kathy Law, Maurice Levasseur, Quentin Libois, John Liggio, Martine Lizotte, Katrina M. Macdonald, Rashed Mahmood, Randall V. Martin, Ryan H. Mason, Lisa A. Miller, Alexander Moravek, Eric Mortenson, Emma L. Mungall, Jennifer G. Murphy, Maryam Namazi, Ann-Lise Norman, Norman T. O'Neill, Jeffrey R. Pierce, Lynn M. Russell, Johannes Schneider, Hannes Schulz, Sangeeta Sharma, Meng Si, Ralf M. Staebler, Nadja S. Steiner, Jennie L. Thomas, Knut von Salzen, Jeremy J. B. Wentzell, Megan D. Willis, Gregory R. Wentworth, Jun-Wei Xu, and Jacqueline D. Yakobi-Hancock
The Arctic is experiencing considerable environmental change with climate warming, illustrated by the dramatic decrease in sea-ice extent. It is important to understand both the natural and perturbed Arctic systems to gain a better understanding of how they will change in the future. This paper summarizes new insights into the relationships between Arctic aerosol particles and climate, as learned over the past five or so years by a large Canadian research consortium, NETCARE.
CO2 flux over young and snow-covered Arctic pack ice in winter and spring
Daiki Nomura, Mats A. Granskog, Agneta Fransson, Melissa Chierici, Anna Silyakova, Kay I. Ohshima, Lana Cohen, Bruno Delille, Stephen R. Hudson, and Gerhard S. Dieckmann
Global high-resolution monthly pCO2 climatology for the coastal ocean derived from neural network interpolation
Goulven G. Laruelle, Peter Landschützer, Nicolas Gruber, Jean-Louis Tison, Bruno Delille, and Pierre Regnier
Ice-nucleating particles in Canadian Arctic sea-surface microlayer and bulk seawater
Victoria E. Irish, Pablo Elizondo, Jessie Chen, Cédric Chou, Joannie Charette, Martine Lizotte, Luis A. Ladino, Theodore W. Wilson, Michel Gosselin, Benjamin J. Murray, Elena Polishchuk, Jonathan P. D. Abbatt, Lisa A. Miller, and Allan K. Bertram
Atmos. Chem. Phys., 17, 10583–10595, https://doi.org/10.5194/acp-17-10583-2017,https://doi.org/10.5194/acp-17-10583-2017, 2017
The ocean is a possible source of atmospheric ice-nucleating particles (INPs). In this study we found that INPs were ubiquitous in the sea-surface microlayer and bulk seawater in the Canadian Arctic. A strong negative correlation was observed between salinity and freezing temperatures (after correcting for freezing point depression). Heat and filtration treatments of the samples showed that the INPs were likely biological material with sizes between 0.02 μm and 0.2 μm in diameter.
Impact of ocean acidification on Arctic phytoplankton blooms and dimethyl sulfide concentration under simulated ice-free and under-ice conditions
Rachel Hussherr, Maurice Levasseur, Martine Lizotte, Jean-Éric Tremblay, Jacoba Mol, Helmuth Thomas, Michel Gosselin, Michel Starr, Lisa A. Miller, Tereza Jarniková, Nina Schuback, and Alfonso Mucci
This study assesses the impact of ocean acidification on phytoplankton and its synthesis of the climate-active gas dimethyl sulfide (DMS), as well as its modulation, by two contrasting light regimes in the Arctic. The light regimes tested had no significant impact on either the phytoplankton or DMS concentration, whereas both variables decreased linearly with the decrease in pH. Thus, a rapid decrease in surface water pH could alter the algal biomass and inhibit DMS production in the Arctic.
The origin of methane in the East Siberian Arctic Shelf unraveled with triple isotope analysis
Célia J. Sapart, Natalia Shakhova, Igor Semiletov, Joachim Jansen, Sönke Szidat, Denis Kosmach, Oleg Dudarev, Carina van der Veen, Matthias Egger, Valentine Sergienko, Anatoly Salyuk, Vladimir Tumskoy, Jean-Louis Tison, and Thomas Röckmann
The Arctic Ocean, especially the Siberian shelves, overlays large areas of subsea permafrost that is degrading. We show that methane with a biogenic origin is emitted from this permafrost. At locations where bubble plumes have been observed, methane can escape oxidation in the surface sediment and rapidly migrate through the very shallow water column of this region to escape to the atmosphere, generating a positive radiative feedback.
Ice core evidence for a 20th century increase in surface mass balance in coastal Dronning Maud Land, East Antarctica
Morgane Philippe, Jean-Louis Tison, Karen Fjøsne, Bryn Hubbard, Helle A. Kjær, Jan T. M. Lenaerts, Reinhard Drews, Simon G. Sheldon, Kevin De Bondt, Philippe Claeys, and Frank Pattyn
The reconstruction of past snow accumulation rates is crucial in the context of recent climate change and sea level rise. We measured ~ 250 years of snow accumulation using a 120 m ice core drilled in coastal East Antarctica, where such long records are very scarce. This study is the first to show an increase in snow accumulation, beginning in the 20th and particularly marked in the last 50 years, thereby confirming model predictions of increased snowfall associated with climate change.
Inorganic carbon cycling and biogeochemical processes in an Arctic inland sea (Hudson Bay)
William J. Burt, Helmuth Thomas, Lisa A. Miller, Mats A. Granskog, Tim N. Papakyriakou, and Leah Pengelly
This study assesses the state of the carbon cycle in Hudson Bay, an ecologically important region of the Canadian Arctic. Results show that river input, sea-ice melt, biological activity, and general circulation patterns all have significant, and regionally dependent, impacts on the carbon cycle. The study also highlights the importance of detailed sampling procedures in highly stratified waters, and reveals that the deep Hudson Bay is primarily filled with waters of Pacific origin.
Imaging air volume fraction in sea ice using non-destructive X-ray tomography
Odile Crabeck, Ryan Galley, Bruno Delille, Brent Else, Nicolas-Xavier Geilfus, Marcos Lemes, Mathieu Des Roches, Pierre Francus, Jean-Louis Tison, and Søren Rysgaard
We present a new non-destructive X-ray-computed tomography technique to quantify the air volume fraction and produce separate 3-D images of air-volume inclusions in sea ice. While the internal layers showed air-volume fractions < 2 %, the ice–air interface (top 2 cm) showed values up to 5 %. As a result of the presence of large bubbles and higher air volume fraction measurements in sea ice, we introduce new perspectives on processes regulating gas exchange at the ice–atmosphere interface.
A comprehensive interpretation of the NEEM basal ice build-up using a multi-parametric approach
Thomas Goossens, Célia J. Sapart, Dorthe Dahl-Jensen, Trevor Popp, Saïda El Amri, and Jean-Louis Tison
This first multi-parametric analysis of the basal ice layer of the NEEM ice core reveals that its formation does not result from a mixing process between local relict ice and the deepest ice layers of the advancing ice sheet during its growth phase. Instead, it is shown that the basal sequence partly originates from melting and refreezing processes acting at the ice/bedrock interface under a well-developed ice sheet. These have partially destroyed the paleoclimatic records of the ice.
Retrieving the paleoclimatic signal from the deeper part of the EPICA Dome C ice core
J.-L. Tison, M. de Angelis, G. Littot, E. Wolff, H. Fischer, M. Hansson, M. Bigler, R. Udisti, A. Wegner, J. Jouzel, B. Stenni, S. Johnsen, V. Masson-Delmotte, A. Landais, V. Lipenkov, L. Loulergue, J.-M. Barnola, J.-R. Petit, B. Delmonte, G. Dreyfus, D. Dahl-Jensen, G. Durand, B. Bereiter, A. Schilt, R. Spahni, K. Pol, R. Lorrain, R. Souchez, and D. Samyn
The oldest paleoclimatic information is buried within the lowermost layers of deep ice cores. It is therefore essential to judge how deep these records remain unaltered. We study the bottom 60 meters of the EPICA Dome C ice core from central Antarctica to show that the paleoclimatic signal is only affected at the small scale (decimeters) in terms of some of the global ice properties. However our data suggest that the time scale has been considerably distorted by mechanical stretching.
Insights into oxygen transport and net community production in sea ice from oxygen, nitrogen and argon concentrations
J. Zhou, B. Delille, F. Brabant, and J.-L. Tison
On the characteristics of sea ice divergence/convergence in the Southern Beaufort Sea
J. V. Lukovich, D. G. Babb, R. J. Galley, R. L. Raddatz, and D. G. Barber
The Cryosphere Discuss., https://doi.org/10.5194/tcd-8-4281-2014,https://doi.org/10.5194/tcd-8-4281-2014, 2014
Revised manuscript not accepted
Parameterization of atmosphere–surface exchange of CO2 over sea ice
L. L. Sørensen, B. Jensen, R. N. Glud, D. F. McGinnis, M. K. Sejr, J. Sievers, D. H. Søgaard, J.-L. Tison, and S. Rysgaard
Measurements of the dissolved inorganic carbon system and associated biogeochemical parameters in the Canadian Arctic, 1974–2009
K. E. Giesbrecht, L. A. Miller, M. Davelaar, S. Zimmermann, E. Carmack, W. K. Johnson, R. W. Macdonald, F. McLaughlin, A. Mucci, W. J. Williams, C. S. Wong, and M. Yamamoto-Kawai
Earth Syst. Sci. Data, 6, 91–104, https://doi.org/10.5194/essd-6-91-2014,https://doi.org/10.5194/essd-6-91-2014, 2014
Formation of gas-phase carbonyls from heterogeneous oxidation of polyunsaturated fatty acids at the air–water interface and of the sea surface microlayer
S. Zhou, L. Gonzalez, A. Leithead, Z. Finewax, R. Thalman, A. Vlasenko, S. Vagle, L.A. Miller, S.-M. Li, S. Bureekul, H. Furutani, M. Uematsu, R. Volkamer, and J. Abbatt
Morphology and distribution of liquid inclusions in young sea ice as imaged by magnetic resonance
R. J. Galley, B. G. T. Else, N.-X. Geilfus, A. A. Hare, D. Isleifson, L. Ryner, D. G. Barber, and S. Rysgaard
Technical Note: On the use of the mushy-layer Rayleigh number for the interpretation of sea-ice-core data
M. Vancoppenolle, D. Notz, F. Vivier, J. Tison, B. Delille, G. Carnat, J. Zhou, F. Jardon, P. Griewank, A. Lourenço, and T. Haskell
Sea ice export through the Fram Strait derived from a combined model and satellite data set
Chao Min, Longjiang Mu, Qinghua Yang, Robert Ricker, Qian Shi, Bo Han, Renhao Wu, and Jiping Liu
Sea ice volume export through the Fram Strait has been studied using varied methods, however, mostly in winter months. Here we report sea ice volume estimates that extend over summer seasons. A recent developed sea ice thickness dataset, in which CryoSat-2 and SMOS sea ice thickness together with SSMI/SSMIS sea ice concentration are assimilated, is used and evaluated in the paper. Results show our estimate is more reasonable than that calculated by satellite data only.
Estimating early-winter Antarctic sea ice thickness from deformed ice morphology
M. Jeffrey Mei, Ted Maksym, Blake Weissling, and Hanumant Singh
Sea ice thickness is hard to measure directly, and current datasets are very limited to sporadically conducted drill lines. However, surface elevation is much easier to measure. Converting surface elevation to ice thickness requires making assumptions about snow depth and density, which leads to large errors (and may not generalize to new datasets). A deep learning method is presented that uses the surface morphology as a direct predictor of sea ice thickness, with testing errors of < 20 %.
On the multi-fractal scaling properties of sea ice deformation
Pierre Rampal, Véronique Dansereau, Einar Olason, Sylvain Bouillon, Timothy Williams, Anton Korosov, and Abdoulaye Samaké
In this article, we look at how the Arctic sea ice cover, as a solid body, behaves on different temporal and spatial scales. We show that the numerical model neXtSIM uses a new approach to simulate the mechanics of sea ice and reproduce the characteristics of how sea ice deforms, as observed by satellite. We discuss the importance of this model performance in the context of simulating climate processes taking place in polar regions, like the exchange of energy between the ocean and atmosphere.
Sea ice volume variability and water temperature in the Greenland Sea
Valeria Selyuzhenok, Igor Bashmachnikov, Robert Ricker, Anna Vesman, and Leonid Bobylev
Brief communication: Pancake ice floe size distribution during the winter expansion of the Antarctic marginal ice zone
Alberto Alberello, Miguel Onorato, Luke Bennetts, Marcello Vichi, Clare Eayrs, Keith MacHutchon, and Alessandro Toffoli
The Cryosphere, 13, 41–48, https://doi.org/10.5194/tc-13-41-2019,https://doi.org/10.5194/tc-13-41-2019, 2019
Existing observations do not provide quantitative descriptions of the floe size distribution for pancake ice floes. This is important during the Antarctic winter sea ice expansion, when hundreds of kilometres of ice cover around the Antarctic continent are composed of pancake floes (D = 0.3–3 m). Here, a new set of images from the Antarctic marginal ice zone is used to measure the shape of individual pancakes for the first time and to infer their size distribution.
What historical landfast ice observations tell us about projected ice conditions in Arctic archipelagoes and marginal seas under anthropogenic forcing
Frédéric Laliberté, Stephen E. L. Howell, Jean-François Lemieux, Frédéric Dupont, and Ji Lei
Ice that forms over marginal seas often gets anchored and becomes landfast. Landfast ice is fundamental to the local ecosystems, is of economic importance as it leads to hazardous seafaring conditions and is also a choice hunting ground for both the local population and large predators. Using observations and climate simulations, this study shows that, especially in the Canadian Arctic, landfast ice might be more resilient to climate change than is generally thought.
Interannual sea ice thickness variability in the Bay of Bothnia
Iina Ronkainen, Jonni Lehtiranta, Mikko Lensu, Eero Rinne, Jari Haapala, and Christian Haas
We quantify the sea ice thickness variability in the Bay of Bothnia using various observational data sets. For the first time we use helicopter and shipborne electromagnetic soundings to study changes in drift ice of the Bay of Bothnia. Our results show that the interannual variability of ice thickness is larger in the drift ice zone than in the fast ice zone. Furthermore, the mean thickness of heavily ridged ice near the coast can be several times larger than that of fast ice.
Improving Met Office seasonal predictions of Arctic sea ice using assimilation of CryoSat-2 thickness
Edward W. Blockley and K. Andrew Peterson
Arctic sea-ice prediction on seasonal time scales is becoming increasingly more relevant to society but the predictive capability of forecasting systems is low. Several studies suggest initialization of sea-ice thickness (SIT) could improve the skill of seasonal prediction systems. Here for the first time we test the impact of SIT initialization in the Met Office's GloSea coupled prediction system using CryoSat-2 data. We show significant improvements to Arctic extent and ice edge location.
Brief communication: Solar radiation management not as effective as CO2 mitigation for Arctic sea ice loss in hitting the 1.5 and 2 °C COP climate targets
Jeff K. Ridley and Edward W. Blockley
The climate change conference held in Paris in 2016 made a commitment to limiting global-mean warming since the pre-industrial era to well below 2 °C and to pursue efforts to limit the warming to 1.5 °C. Since global warming is already at 1 °C, the 1.5 °C can only be achieved at considerable cost. It is thus important to assess the risks associated with the higher target. This paper shows that the decline of Arctic sea ice, and associated impacts, can only be halted with the 1.5 °C target.
Reflective properties of melt ponds on sea ice
Aleksey Malinka, Eleonora Zege, Larysa Istomina, Georg Heygster, Gunnar Spreen, Donald Perovich, and Chris Polashenski
Melt ponds occupy a large part of the Arctic sea ice in summer and strongly affect the radiative budget of the atmosphere–ice–ocean system. The melt pond reflectance is modeled in the framework of the radiative transfer theory and validated with field observations. It improves understanding of melting sea ice and enables better parameterization of the surface in Arctic atmospheric remote sensing (clouds, aerosols, trace gases) and re-evaluating Arctic climatic feedbacks at a new accuracy level.
The color of melt ponds on Arctic sea ice
Peng Lu, Matti Leppäranta, Bin Cheng, Zhijun Li, Larysa Istomina, and Georg Heygster
It is the first time that the color of melt ponds on Arctic sea ice was quantitatively and thoroughly investigated. We answer the question of why the color of melt ponds can change and what the physical and optical reasons are that lead to such changes. More importantly, melt-pond color was provided as potential data in determining ice thickness, especially under the summer conditions when other methods such as remote sensing are unavailable.
On the retrieval of sea ice thickness and snow depth using concurrent laser altimetry and L-band remote sensing data
Lu Zhou, Shiming Xu, Jiping Liu, and Bin Wang
The Cryosphere, 12, 993–1012, https://doi.org/10.5194/tc-12-993-2018,https://doi.org/10.5194/tc-12-993-2018, 2018
This work proposes a new data synergy method for the retrieval of sea ice thickness and snow depth by using colocating L-band passive remote sensing and active laser altimetry. Physical models are adopted for the retrieval, including L-band radiation model and buoyancy relationship. Covariability of snow depth and total freeboard is further utilized to mitigate resolution differences and improve retrievability. The method can be applied to future campaigns including ICESat-2 and WCOM.
A network model for characterizing brine channels in sea ice
Ross M. Lieblappen, Deip D. Kumar, Scott D. Pauls, and Rachel W. Obbard
We imaged first-year sea ice using micro-computed tomography to visualize, capture, and quantify the 3-D complex structure of salt water channels weaving through sea ice. From these data, we then built a mathematical network to better understand the pathways transporting heat, gases, and salts between the ocean and the atmosphere. Powered with this structural knowledge, we can create new modeled brine channels for a given sea ice depth and temperature that accurately mimic field conditions.
Impact of rheology on probabilistic forecasts of sea ice trajectories: application for search and rescue operations in the Arctic
Matthias Rabatel, Pierre Rampal, Alberto Carrassi, Laurent Bertino, and Christopher K. R. T. Jones
Large deviations still exist between sea ice forecasts and observations because of both missing physics in models and uncertainties on model inputs. We investigate how the new sea ice model neXtSIM is sensitive to uncertainties in the winds. We highlight and quantify the role of the internal forces in the ice on this sensitivity and show that neXtSIM is better at predicting sea ice drift than a free-drift (without internal forces) ice model and is a skilful tool for search and rescue operations.
Arctic sea ice signatures: L-band brightness temperature sensitivity comparison using two radiation transfer models
Friedrich Richter, Matthias Drusch, Lars Kaleschke, Nina Maaß, Xiangshan Tian-Kunze, and Susanne Mecklenburg
L-band (1.4 GHz) brightness temperatures from ESA's Soil Moisture and Ocean Salinity SMOS mission have been used to derive thin sea ice thickness. However, the brightness temperature measurements can potentially be assimilated directly in forecasting systems reducing the data latency and providing a more consistent first guess. We studied the forward (observation) operator that translates geophysical sea ice parameters from the ECMWF Ocean ReAnalysis Pilot 5 (ORAP5) into brightness temperatures.
Mechanisms influencing seasonal to inter-annual prediction skill of sea ice extent in the Arctic Ocean in MIROC
Jun Ono, Hiroaki Tatebe, Yoshiki Komuro, Masato I. Nodzu, and Masayoshi Ishii
Sea ice in the Arctic Ocean has experienced rapid decline since the beginning of satellite observations. To assess the predictability of sea ice extent (SIE) in the Arctic Ocean and to clarify the underlying physical processes, we conducted prediction experiments using an initialized climate model (MIROC5). The present study suggests that subsurface ocean heat content originating from the North Atlantic contributes to the skillful prediction of winter SIE at lead times up to 11 months.
Floe-size distributions in laboratory ice broken by waves
Agnieszka Herman, Karl-Ulrich Evers, and Nils Reimer
In regions close to the ice edge, sea ice is composed of many separate ice floes of different sizes and shapes. Strong fragmentation is caused mainly by ice breaking by waves coming from the open ocean. At present, this process, although recognized as important for many other physical processes, is not well understood. In this study we present results of a laboratory study of ice breaking by waves, and we provide interpretation of those results that may guide analysis of other similar datasets.
The Arctic sea ice cover of 2016: a year of record-low highs and higher-than-expected lows
Alek A. Petty, Julienne C. Stroeve, Paul R. Holland, Linette N. Boisvert, Angela C. Bliss, Noriaki Kimura, and Walter N. Meier
There was significant scientific and media attention surrounding Arctic sea ice in 2016, due primarily to the record-warm air temperatures and low sea ice conditions observed at the start of the year. Here we quantify and assess the record-low monthly sea ice cover in winter, spring and fall, and the lack of record-low sea ice conditions in summer. We explore the primary drivers of these monthly sea ice states and explore the implications for improved summer sea ice forecasting.
Consistent biases in Antarctic sea ice concentration simulated by climate models
Lettie A. Roach, Samuel M. Dean, and James A. Renwick
This paper evaluates Antarctic sea ice simulated by global climate models against satellite observations. We find biases in high-concentration and low-concentration sea ice that are consistent across the population of 40 models, in spite of the differences in physics between different models. Targeted model experiments show that biases in low-concentration sea ice can be significantly reduced by enhanced lateral melt, a result that may be valuable for sea ice model development.
Frazil-ice growth rate and dynamics in mixed layers and sub-ice-shelf plumes
David W. Rees Jones and Andrew J. Wells
Frazil or granular ice grows rapidly from turbulent water cooled beneath its freezing temperature. We analyse numerical models of a population of ice crystals to provide insight into the treatment of frazil ice in large-scale models and hence in the environment. We determine critical conditions for explosively rapid frazil growth. We show that frazil-ice processes impact whether a plume of ice shelf water beneath an Antarctic ice shelf intrudes at depth or reaches the end of the shelf.
How much should we believe correlations between Arctic cyclones and sea ice extent?
Jamie G. L. Rae, Alexander D. Todd, Edward W. Blockley, and Jeff K. Ridley
Several studies have highlighted links between Arctic summer storms and September sea ice extent in observations. Here we use model and reanalysis data to investigate the sensitivity of such links to the analytical methods used, in order to determine their robustness. The links were found to depend on the resolution of the model and dataset, the method used to identify storms and the time period used in the analysis. We therefore recommend caution when interpreting the results of such studies.
Optical properties of sea ice doped with black carbon – an experimental and radiative-transfer modelling comparison
Amelia A. Marks, Maxim L. Lamare, and Martin D. King
Arctic sea ice extent is declining rapidly. Prediction of sea ice trends relies on sea ice models that need to be evaluated with real data. A realistic sea ice environment is created in a laboratory by the Royal Holloway sea ice simulator and is used to show a sea ice model can replicate measured properties of sea ice, e.g. reflectance. Black carbon, a component of soot found in atmospheric pollution, is also experimentally shown to reduce the sea ice reflectance, which could exacerbate melting.
Relationships between Arctic sea ice drift and strength modelled by NEMO-LIM3.6
David Docquier, François Massonnet, Antoine Barthélemy, Neil F. Tandon, Olivier Lecomte, and Thierry Fichefet
Our study provides a new way to evaluate the performance of a climate model regarding the interplay between sea ice motion, area and thickness in the Arctic against different observation datasets. We show that the NEMO-LIM model is good in that respect and that the relationships between the different sea ice variables are complex. The metrics we developed can be used in the framework of the Coupled Model Intercomparison Project 6 (CMIP6), which will feed the next IPCC report.
Wave-induced stress and breaking of sea ice in a coupled hydrodynamic discrete-element wave–ice model
Agnieszka Herman
It is often assumed that ocean waves break sea ice into floes with sizes depending on wavelength. The results of this modeling study (in agreement with some earlier observations and models) suggest that this is not the case; instead the sizes of ice floes produced by wave breaking depend only on ice thickness and mechanical properties. This may have important consequences for predicting sea ice response to oceanic and atmospheric forcing in regions where sea ice is influenced by waves.
Intercomparison of snow depth retrievals over Arctic sea ice from radar data acquired by Operation IceBridge
Ron Kwok, Nathan T. Kurtz, Ludovic Brucker, Alvaro Ivanoff, Thomas Newman, Sinead L. Farrell, Joshua King, Stephen Howell, Melinda A. Webster, John Paden, Carl Leuschen, Joseph A. MacGregor, Jacqueline Richter-Menge, Jeremy Harbeck, and Mark Tschudi
Since 2009, the ultra-wideband snow radar on Operation IceBridge has acquired data in annual campaigns conducted during the Arctic and Antarctic springs. Existing snow depth retrieval algorithms differ in the way the air–snow and snow–ice interfaces are detected and localized in the radar returns and in how the system limitations are addressed. Here, we assess five retrieval algorithms by comparisons with field measurements, ground-based campaigns, and analyzed fields of snow depth.
Winter sea ice export from the Laptev Sea preconditions the local summer sea ice cover and fast ice decay
Polona Itkin and Thomas Krumpen
By means of airborne sea ice thickness surveys, remote sensing data and results from a numerical model, we show that winter ice dynamic in the Laptev Sea has a preconditioning effect on local summer ice extent in addition to atmospheric processes acting on the ice cover between May and September. We conclude that the observed tendency towards an increased ice export further accelerates pack ice retreat in summer and fast ice decay.
Sea ice assimilation into a coupled ocean–sea ice model using its adjoint
Nikolay V. Koldunov, Armin Köhl, Nuno Serra, and Detlef Stammer
The paper describes one of the first attempts to use the so-called adjoint data assimilation method to bring Arctic Ocean model simulations closer to observation, especially in terms of the sea ice. It is shown that after assimilation the model bias in simulating the Arctic sea ice is considerably reduced. There is also additional improvement in the sea ice thickens representation that is not assimilated directly.
Modelling radiative transfer through ponded first-year Arctic sea ice with a plane-parallel model
Torbjørn Taskjelle, Stephen R. Hudson, Mats A. Granskog, and Børge Hamre
Brief communication: Increasing shortwave absorption over the Arctic Ocean is not balanced by trends in the Antarctic
Christian Katlein, Stefan Hendricks, and Jeffrey Key
In the public debate, increasing sea ice extent in the Antarctic is often highlighted as counter-indicative of global warming. Here we show that the slight increases in Antarctic sea ice extent are not able to counter Arctic losses. Using bipolar satellite observations, we demonstrate that even in the Antarctic polar ocean solar shortwave energy absorption is increasing in accordance with strongly increasing shortwave energy absorption in the Arctic Ocean rather than compensating Arctic losses.
Wave–ice interactions in the neXtSIM sea-ice model
Timothy D. Williams, Pierre Rampal, and Sylvain Bouillon
As the Arctic sea ice extent drops, more ship traffic seeks to take advantage of this, and a need for better wave and sea ice forecasts arises. One aspect of this is the location of the sea ice edge. The waves here can be quite large, but they die away as they travel into the ice. This causes momentum to be transferred from the waves to the ice, causing ice drift. However, our study found that the effect of the wind drag had more impact on the ice edge position than the waves.
Ice bridges and ridges in the Maxwell-EB sea ice rheology
Véronique Dansereau, Jérôme Weiss, Pierre Saramito, Philippe Lattes, and Edmond Coche
A new mechanical framework is used to model the drift of sea ice in a narrow channel between Greenland and Ellesmere Island. It is able to reproduce its main features : curved cracks, ice "bridges" that stop the flow of ice for several months of the year and some thick, strongly localized ridged ice. The simulations suggest that a mechanical weakening of the sea ice cover can shorten the lifespan of ice bridges and result in an increased export of ice through the narrow channels of the Arctic.
Comparison of CryoSat-2 and ENVISAT radar freeboard over Arctic sea ice: toward an improved Envisat freeboard retrieval
Kevin Guerreiro, Sara Fleury, Elena Zakharova, Alexei Kouraev, Frédérique Rémy, and Philippe Maisongrande
We analyse CryoSat-2 and Envisat freeboard height discrepancy over Arctic sea ice and we study the potential role of ice roughness. Based on our results, we build a CryoSat-2-like version of Envisat freeboard height. The improved Envisat freeboard is converted to sea ice draught and compared to in situ mooring observations to demonstrate the potential of our methodology to produce accurate ice thickness estimates over the 2002–2012 period.
Open-source sea ice drift algorithm for Sentinel-1 SAR imagery using a combination of feature tracking and pattern matching
Stefan Muckenhuber and Stein Sandven
Sea ice drift has a strong impact on sea ice distribution on different temporal and spatial scales. An open-source sea ice drift algorithm for Sentinel-1 satellite imagery is introduced based on the combination of feature tracking and pattern matching. The algorithm is designed to utilise the respective advantages of the two approaches and allows drift calculation at user-defined locations.
Method to characterize directional changes in Arctic sea ice drift and associated deformation due to synoptic atmospheric variations using Lagrangian dispersion statistics
Jennifer V. Lukovich, Cathleen A. Geiger, and David G. Barber
In this study we develop a framework to characterize directional changes in sea ice drift and associated deformation in response to atmospheric forcing. Lagrangian dispersion statistics applied to ice beacons deployed in a triangular configuration in the Beaufort Sea capture a shift in ice dynamical regimes and local differences in deformation. This framework contributes to diagnostic development relevant for ice hazard assessments and forecasting required by indigenous communities and industry.
A weekly Arctic sea-ice thickness data record from merged CryoSat-2 and SMOS satellite data
Robert Ricker, Stefan Hendricks, Lars Kaleschke, Xiangshan Tian-Kunze, Jennifer King, and Christian Haas
We developed the first merging of CryoSat-2 and SMOS sea-ice thickness retrievals. ESA's Earth Explorer SMOS satellite can detect thin sea ice, whereas its companion CryoSat-2, designed to observe thicker perennial sea ice, lacks sensitivity. Using these satellite missions together completes the picture of the changing Arctic sea ice and provides a more accurate and comprehensive view on the actual state of Arctic sea-ice thickness.
Sea-ice deformation in a coupled ocean–sea-ice model and in satellite remote sensing data
Gunnar Spreen, Ron Kwok, Dimitris Menemenlis, and An T. Nguyen
Impacts of freshwater changes on Antarctic sea ice in an eddy-permitting sea-ice–ocean model
Verena Haid, Doroteaciro Iovino, and Simona Masina
Since the Antarctic sea ice extent shows a recent increase, we investigate the sea ice response to changed amount and distribution of surface freshwater addition in the Southern Ocean with the ocean–sea ice model NEMO/LIM2. We find that freshwater addition within the range of current estimates increases the ice extent, but higher amounts could have an opposing effect. The freshwater distribution is of great influence on the ice dynamics and the ice thickness is strongly influenced by it.
A simple model for the evolution of melt pond coverage on permeable Arctic sea ice
Predrag Popović and Dorian Abbot
During summer, a large portion of sea ice in the Arctic is typically covered with meltwater. We present a simple model for the evolution of melt ponds on permeable sea ice that both fits observations and allows us to understand the behavior of melt ponds in a way that is often not possible with more complex models. We use this model to show that pond coverage will increase under global warming. This work is important as melt ponds affect the overall reflectance of sea ice.
Brief communication: Impacts of ocean-wave-induced breakup of Antarctic sea ice via thermodynamics in a stand-alone version of the CICE sea-ice model
Luke G. Bennetts, Siobhan O'Farrell, and Petteri Uotila
A numerical model is used to investigate how Antarctic sea ice concentration and volume are affected by increased melting caused by ocean-wave breakup of the ice. When temperatures are high enough to melt the ice, concentration and volume are reduced for ~ 100 km into the ice-covered ocean. When temperatures are low enough for ice growth, the concentration recovers, but the reduced volume persists.
Interactions between Antarctic sea ice and large-scale atmospheric modes in CMIP5 models
Serena Schroeter, Will Hobbs, and Nathaniel L. Bindoff
Observed trends of Antarctic sea ice are not reproduced by global climate models. We examine observed and simulated interactions between sea ice and large-scale atmospheric variability, showing that global climate models generally capture observed interactions during the season of sea ice advance, but not during sea ice retreat. Most models overestimate the zonally symmetric influence of the dominant atmospheric mode on sea ice, while the importance of tropical variability is underestimated.
Fram Strait sea ice export variability and September Arctic sea ice extent over the last 80 years
Lars H. Smedsrud, Mari H. Halvorsen, Julienne C. Stroeve, Rong Zhang, and Kjell Kloster
Export of Arctic sea ice area southwards through the Fram Strait from 1935 to 2014 is calculated based on satellite radar images and surface pressure observations. The annual mean export is 880 000 km2, representing 10 % of the Arctic sea ice area. In recent years the export has been above 1 million km2, and there are positive trends over the last 30 years. Increased ice export during spring and summer contributes to more open water in September, and this correlations has increased over time.
Operational algorithm for ice–water classification on dual-polarized RADARSAT-2 images
Natalia Zakhvatkina, Anton Korosov, Stefan Muckenhuber, Stein Sandven, and Mohamed Babiker
The presented fully automated algorithm distinguishes open water (rough/calm) and sea ice based on dual-polarized RS2 SAR images. Texture features are used for Support Vector Machines supervised image classification. The algorithm includes pre-processing and validation procedures. More than 2700 scenes were processed and the results show the good discrimination between open water and sea ice areas with accuracy 91 % compared with ice charts produced by MET Norway service.
Circumpolar polynya regions and ice production in the Arctic: results from MODIS thermal infrared imagery from 2002/2003 to 2014/2015 with a regional focus on the Laptev Sea
Andreas Preußer, Günther Heinemann, Sascha Willmes, and Stephan Paul
We present spatial and temporal characteristics of 17 Arctic polynya regions. By using an energy balance model, daily thin-ice thickness distributions are derived from TIR satellite and atmospheric reanalysis data. All polynyas combined yield an average ice production of about 1811 km3 per winter. Interestingly, we find distinct regional differences in calculated trends over the last 13 years. Finally, we set a special focus on the Laptev Sea region and its relation to the Transpolar Drift.
In situ field measurements of the temporal evolution of low-frequency sea-ice dielectric properties in relation to temperature, salinity, and microstructure
Megan O'Sadnick, Malcolm Ingham, Hajo Eicken, and Erin Pettit
Non-destructive in situ monitoring of sea-ice microstructure is of value to sea-ice research and operations but remains elusive to date. We relate in situ measurements of sea-ice dielectric properties at frequencies of 10 to 95 Hz to ice temperature, salinity, and microstructure. Results support the possible use of low-frequency electric measurements to monitor the seasonal evolution of brine volume fraction, pore volume, and connectivity of pore space in sea ice.
Benefits of assimilating thin sea ice thickness from SMOS into the TOPAZ system
Jiping Xie, François Counillon, Laurent Bertino, Xiangshan Tian-Kunze, and Lars Kaleschke
As a potentially operational daily product, the SMOS-Ice can improve the statements of sea ice thickness and concentration. In this study, focusing on the SMOS-Ice data assimilated into the TOPAZ system, the quantitative evaluation for the impacts and the concerned comparison with the present observation system are valuable to understand the further improvement of the accuracy of operational ocean forecasting system.
Reflective properties of white sea ice and snow
Aleksey Malinka, Eleonora Zege, Georg Heygster, and Larysa Istomina
The number of melt ponds on Arctic summer sea ice and its reflectance are required for better climate modeling and weather prediction. In order to derive these quantities from optical satellite observations, simple analytical formulas for the bidirectional reflectance factor and albedo at direct and diffuse incidence are derived from basic assumptions and verified with in situ measurements made during the expedition ARK-XXVII/3 of research vessel Polarstern in 2012.
On retrieving sea ice freeboard from ICESat laser altimeter
Kirill Khvorostovsky and Pierre Rampal
We analyse two methods of freeboard retrieval from ICESat satellite data that were used to derive the two widely used Arctic sea ice thickness products. We show that although different factors result in significant local differences between freeboards, they roughly compensate each other with respect to overall freeboard estimation. Thus the difference found between the sea ice thickness datasets should be attributed to different parameters used in the freeboard-to-thickness conversion.
The EUMETSAT sea ice concentration climate data record
Rasmus T. Tonboe, Steinar Eastwood, Thomas Lavergne, Atle M. Sørensen, Nicholas Rathmann, Gorm Dybkjær, Leif Toudal Pedersen, Jacob L. Høyer, and Stefan Kern
The EUMETSAT sea ice climate record (ESICR) is based on the Nimbus 7 SMMR (1978–1987), the SSM/I (1987–2009), and the SSMIS (2003–today) microwave radiometer data. It uses a combination of two sea ice concentration algorithms with dynamical tie points, explicit atmospheric correction using numerical weather prediction data for error reduction and it comes with spatially and temporally varying uncertainty estimates describing the residual uncertainties.
The impact of melt ponds on summertime microwave brightness temperatures and sea-ice concentrations
Stefan Kern, Anja Rösel, Leif Toudal Pedersen, Natalia Ivanova, Roberto Saldo, and Rasmus Tage Tonboe
Sea ice, frozen seawater floating on polar oceans, is covered by meltwater puddles, so-called melt ponds, during summer. Methods used to compute Arctic sea-ice concentration (SIC) from microwave satellite data are influenced by melt ponds. We apply eight such methods to one microwave dataset and compare SIC with visible data. We conclude all methods fail to distinguish melt ponds from leads between ice floes; SIC biases are negative (positive) for ponded (non-ponded) sea ice and can exceed 20 %.
Mechanism of seasonal Arctic sea ice evolution and Arctic amplification
Kwang-Yul Kim, Benjamin D. Hamlington, Hanna Na, and Jinju Kim
Analysis reveals that "Arctic amplification", lower tropospheric winter temperature rise in the Arctic, is due to sea ice melting and the resulting increase in the amount of turbulent heat flux from the ocean. As a result of increased turbulent heat flux, lower atmosphere warms up, resulting in increased downward longwave radiation. A detailed physical mechanism is presented together with an explanation why this positive feedback process is currently possible in the Barents–Kara seas.
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Temporal evolution of pCO2 profiles in sea ice in the Bellingshausen Sea, Antarctica (Oct. 2007), shows that physical and thermodynamic processes control the CO2 system in the ice. We show that each cooling/warming event was associated with an increase/decrease in the brine salinity, TA, TCO2, and in situ brine and bulk ice pCO2. Thicker snow covers reduced the amplitude of these changes. Both brine and bulk ice pCO2 were undersaturated, causing the sea ice to act as a sink for atmospheric CO2.
Temporal evolution of pCO2 profiles in sea ice in the Bellingshausen Sea, Antarctica (Oct....


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