The Structure, Evolution, Dynamics and Cloud and Precipitation Characteristics of Extreme Summer Arctic Cyclones Revealed Through Comprehensive Life Cycle Studies

通过综合生命周期研究揭示极端夏季北极气旋的结构、演化、动力学以及云和降水特征

• 批准号: 1951757
• 负责人: Jonathan Martin
• 金额: $ 52.19万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1951757&HistoricalAwards=false
• 关键词: Structure; Evolution; Dynamics; Cloud; Precipitation

The cyclones of the Arctic summer pack an extra punch as they strike when the region is at its most vulnerable. The sea ice cover that protects the ocean surface from storm winds in winter is thinned by summer melt, allowing the winds to push the ice apart and mix up warmer subsurface water that promotes further melting. The lack of ice cover in summer also allows the winds to drive ocean waves which erode coastlines, where the warming of recent decades has thawed permafrost and removed the protective skirt of landfast ice. Fortunately summer Arctic cyclones are weaker than their winter counterparts, but recent work suggests a strengthening trend in summer. The "Great Arctic Cyclone" of August 2012 was stronger than all but a dozen of the winter cyclones in the 30 year record of pan-Arctic observations from weather satellites.The impacts of Arctic cyclones and their connection to sea ice decline has prompted interest in their structure, dynamics, and cloud microphysics. Naturally they have much in common with the more familiar cyclones of the middle latitudes, but there are interesting differences: they are often larger, sometimes covering most of the Arctic basin, they are not closely connected to regions of strong temperature contrast and fast jet streams, they can continue to intensify even after they occlude, and their clouds are unusually abundant in liquid droplets (as opposed to ice particles). The abundance of liquid water in the clouds increases the downwelling infrared radiation they generate, warming the lower atmosphere and promoting sea ice melt.Work under this award uses a combination of satellite observations and meteorological data (including winds, sea level pressure, moisture, and temperature) to investigate summer Arctic cyclones at various stages in their lifecycles. The cloud radar and lidar instruments on the NASA A-Train satellite constellation provide cross sections through the cyclones, and data for specific stages of cyclone lifecycles are identified according to their sea level pressure. The observational analysis is complemented by computer simulations using the Weather Research and Forecasting model. One question addressed is whether there are clues in the large-scale environment that could be used to determine which cyclones will grow to extreme size and intensity.The project has broader impacts due to the strong impacts of summer cyclones on Arctic sea ice and coastal erosion, as noted above. The project also supports two graduate students and employs undergraduate students on an hourly basis, thereby promoting the education of the next generation of researchers in this area.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

当该地区最脆弱时，北极夏季的旋风将额外打击。 夏天融化的冬季保护海面免受暴风雨的侵害的海冰盖，使风能将冰拆开并混合更温暖的地下水，从而促进进一步的融化。 夏季缺乏冰盖还使风驱动海浪，侵蚀海岸线，最近几十年的变暖使永久冻土融化，并取下了防护冰的防护裙。 幸运的是，夏季北极气旋比冬季的旋风弱，但最近的工作表明夏季的趋势正在加强。 2012年8月的“北极旋风”在30年的泛北极观测记录中，比冬季卫星的30年记录中的“大北极气旋”都要强，北极旋风的观察结果及其与海冰下降的影响引起了对其结构，动态和云微观物理学的兴趣。自然地，它们与中纬度的更熟悉的旋风有很多共同点，但是存在有趣的差异：它们通常更大，有时覆盖大多数北极盆地，它们与强度强度和快速喷气流的区域并没有紧密相关，即使在遮挡和云中，它们也可以继续加强，并且它们在液体液滴中也具有相反的冰点（与冰的相反，它们都具有相反的冰点。 云层中的液态水丰富增加了它们产生的下降红外辐射，使大气层变暖并促进海冰融化。在此奖项下，工作使用了卫星观测和气象数据（包括风，海平面压力，水分，水分和温度）的结合，以调查其生命周期的各个阶段的夏季北极cyclone。 NASA A-Train卫星星座上的云雷达和激光仪通过旋风提供了横截面，并且根据其海平面压力鉴定了旋风生命周期特定阶段的数据。 使用天气研究和预测模型，通过计算机模拟来补充观察性分析。 解决的一个问题是，在大规模环境中是否有线索可以用来确定哪些旋风将增长到极端的大小和强度。由于夏季旋风对北极海冰和沿海侵蚀的强烈影响，该项目的影响更大，如上所述。 该项目还为两名研究生提供支持，并每小时雇用本科生，从而促进了该领域的下一代研究人员的教育。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响审查标准通过评估来获得支持的。