What is Wind shear?
'''Wind shear''' is a difference in either [[wind speed]] or [[direction]] over a fairly short distance in the [[atmosphere]]. Wind shear can be divided into two different types: ''horizontal'' and ''vertical wind shear''. [[Image:Microburstnasa.JPG|thumb|right|250px|[[NASA]] schematic of the downward motion of the air until it hits ground.]] ==When wind shear is observed== [[Weather]] situations when the Wind shear is observed happen: *At ''weather fronts'' when the [[temperature]] difference across the front is 5 °C or more, and the front moves at 15 [[Knot (speed)|kt]] or faster. *At ''low level jets'' when a significant low level vertical wind shear can develop near the lower portion of the low level jet. *At ''mountains'' when winds blow over and create vertical shear on the lee side.<ref>National Center for Atmospheric Research. [http://www.ucar.edu/communications/quarterly/spring06/trex.jsp T-REX: Catching the Sierra’s waves and rotors] {{Webarchive|url=https://web.archive.org/web/20090221180626/http://www.ucar.edu/communications/quarterly/spring06/trex.jsp |date=2009-02-21 }} Retrieved on 2006-10-21.</ref> *At ''inversions'' when on a clear and calm night a radiation inversion is formed near the ground. *At ''downbursts'' when an outflow boundary moves away from a [[thunderstorm]]. *At ''sailing'' when wind shear affects [[sailboat]]s by presenting a different wind speed and direction at different heights along the sailing mast. ==Related pages== *[[Airplane]] *[[Refraction]] ==Notes== {{reflist}} ==Other websites== {{commonscat|Wind shear}} *[http://www.nsdl.arm.gov/Library/glossary.shtml#wind_shear National Science Digital Library - Wind shear] {{Webarchive|url=https://web.archive.org/web/20050420085336/http://www.nsdl.arm.gov/Library/glossary.shtml#wind_shear |date=2005-04-20 }} {{Wind}} [[Category:Winds]]