Hydrologic Responses to a Shrinking Arctic Sea Ice Cover

这项工作将检验一个假设，即北极海冰和北方高纬度积雪的减少将引起北极地区降水量（P）和净降水量（P-E）的季节性、空间分布和大小的变化，这沿着气温的变化，对北冰洋的淡水收支和格陵兰冰盖的质量平衡产生影响。研究人员预计：（a）海冰的减少将导致北冰洋和周边海域的可用水蒸气增加，在秋季和冬季最为明显，因为在这两个季节，延迟的成冰和较薄的冰将促使大量热量和水分垂直流入大气层;（B）海冰和陆地积雪的减少将引起北极环流模式的变化，从而引起水汽会聚模式的变化，在秋季和冬季由增强的垂直热通量驱动，在温暖季节由北冰洋和周围陆地上改变的差异加热驱动;（c）位于北冰洋的“顺风”处以及邻近（目前）部分被冰覆盖的东格陵兰海和巴芬湾，格陵兰冰盖将通过对积累和表面融化的影响感受到这些变化。2分析工具将是Polar WRF，这是一个最近开发的针对极地应用的区域气候模式。控制模拟将进行几个北极地区，重点是近年来的特点是极低的9月海冰范围，横向强迫提供的NCEP/NCAR再分析，海冰条件规定的卫星观测。生成的关键水文变量（可降水量，降水量，蒸汽通量收敛，净降水量，温度）和大气环流的字段将与那些从一系列实验与改变海冰和积雪。这些将包括模拟气候最大冬季冰的范围和浓度通过年度周期，规定的减少冰的范围和浓度大于观察到的，100%和0%的陆地积雪覆盖保持在年度周期，但观察到的海冰条件，和观察到的海冰条件，但增加海面温度在夏季开放水域。

This effort will test the hypothesis that the loss of arctic sea ice and northern high latitude snow cover will invoke changes in the seasonality, spatial distribution and magnitudes of precipitation (P) and net precipitation (P-E) over the Arctic, which along with attendant changes in temperature, have ramifications for the freshwater budget of the Arctic Ocean and the mass balance of the Greenland ice sheet.The researchers expect that: (a) sea ice loss will lead to an increase in available water vapor over the Arctic Ocean and peripheral seas, most pronounced in autumn and winter, when delayed ice formation and thinner ice will promote large vertical fluxes of heat and moisture into the atmosphere; (b) loss of sea ice and terrestrial snow cover will invoke changes in arctic circulation patterns and hence patterns of water vapor convergence, driven in autumn and winter by enhanced vertical heat fluxes and during the warm season by altered differential heating over the Arctic Ocean and surrounding land; (c) in lying "downwind" of the Arctic Ocean as well as adjacent to the (presently) partially ice-covered East Greenland Sea and Baffin Bay, the Greenland ice sheet will feel these changes both through impacts on accumulation and surface melt.The analysis tool will be Polar WRF, a recently developed regional climate model optimized for polar applications. Control simulations will be conducted for several arctic domains, focusing on recent years which are characterized by extremely low September sea ice extent, with lateral forcing supplied from the NCEP/NCAR reanalysis, and sea ice conditions prescribed from satellite-based observations. Generated fields of key hydrologic variables (precipitable water, precipitation, vapor flux convergence, net precipitation, temperature) and atmospheric circulation will be contrasted with those from a series of experiments with altered sea ice and snow cover. These will include simulations with climatological maximum winter ice extent and concentration through the annual cycle, prescribed reductions in ice extent and concentration larger than those observed, 100% and 0% terrestrial snow cover maintained over the annual cycle but with observed sea ice conditions, and observed sea ice conditions but with increased sea surface temperature over open water areas in summer.