Impacts of reduced sea ice on atmospheric heat, precipitation rates, and ice production

提供资金是为了更好地了解近年来北冰洋吸收的额外夏季热量损失的速度、去向、降水模式如何变化以及这些变化对秋季冰产量的反馈。这些目标将通过一系列精心设计的区域大气模拟研究来实现。天气研究与预报（WRF）模式将用于覆盖北冰洋的一个区域，分辨率为60公里，在太平洋区域嵌套20公里网格。模型评估将使用SHEBA、Barrow、Eureka和Tiksi的观测数据，以及新的2米气温数据集和质量控制无线电探空仪探测的新汇编进行。模式的横向边界条件将取自1989 ？2010. 配对实验将在每年秋季进行(9月？)，其中规定的海冰被设定为低冰或高冰状态，定义为同期观测到的冰浓度的第25或第75分位数。研究的重点将是这些成对运行的大气特性的差异，如温度、分层、降水和大气柱热收支的组成。将采用不同区域的综合分析和热收支计算，年差场将与以北极涛动为代表的大尺度环流有关。然后将用一个单独的动力-热力学拉格朗日冰模型来探讨低冰和高冰运行的不同大气条件的影响，以确定低冰情况下秋季和初冬的冰增长是否足以补充夏季损失的冰，以及这种补充是否在近年来由于冬季变暖而受到影响。这项研究的结果将为理解近年来观测到的北极海冰范围急剧和异常减少的后果提供第一步。

Funds are provided to better understand how rapidly the extra summer heat absorbed in the Arctic Ocean in recent years is lost, where it goes, how precipitation patterns change, and what the feedbacks of these changes are on fall ice production. These objectives will be addressed through a series of carefully crafted regional atmospheric modeling studies. The Weather Research and Forecasting (WRF) model will be used in a domain covering the Arctic Ocean at a resolution of 60 km with a nested 20-km grid in the Pacific sector. Model evaluation will be performed using observations from SHEBA, Barrow, Eureka, and Tiksi as well as a new 2-m air temperature data set and a new compilation of quality-controlled radiosonde soundings. Lateral boundary conditions for the model will be taken from the ERA-Interim Reanalysis for the years 1989 ? 2010. Paired experiments will be run for the fall of each year (September ? December) in which the prescribed sea ice is set to either low-ice or high-ice conditions, defined as the 25th or 75th quantile of the observed ice concentration over the same period. The focus of study will be the difference for these paired runs in atmospheric properties such as temperature, stratification, precipitation, and the components of the heat budget of the atmospheric column. Composite analysis and heat budget calculations for different regions will be employed and the yearly difference fields will be related to the large-scale circulation as represented by the Arctic Oscillation. The implications of the different atmospheric conditions from the low-ice and high-ice runs will then be explored with a separate dynamic-thermodynamic Lagrangian ice model to determine if the ice growth in the fall and early winter is sufficient in the low-ice case to replenish the ice lost in the summer and if this replenishment has suffered in recent years due to winter warming. The results of this study will provide a first step in understanding the consequences of the dramatic and anomalous reductions in arctic sea ice extent observed in recent years.