Collaborative Research: Critical Issues on Cold Region Precipitation Characteristics

到达地球表面的降水类型在很大程度上取决于低对流层温度廓线。 强烈和持续的逆温，在寒冷的季节在北极地区的一个独特的垂直廓线，降水类型的确定提出了独特的挑战。 在其他地区，地表气温可以作为这种情况的预测因子，但这种测量方法不能用于高纬度地区。 这一合作研究项目将解决与降水类型有关的一些关键问题，以便更好地了解与泛北极陆地地区气温上升有关的不同降水类型频率变化的时空模式。 研究人员将确定与高纬度地区每种降水类型相关的大气和其他环境条件。 他们将利用北极陆地地区的历史台站记录，利用各种统计分析和绘图工具汇编每种降水特征的频率。 他们将分析这些数据，以提高气候和水文模型模拟降雪条件的能力，以评估水文循环和能源预算的潜在变化。 研究人员还计划研究降水类型的变化与主要大气环流模式的短期波动（而不是背景长期变暖趋势）有多大关系。项目结果有望增强有关降水特征如何随大气条件变化而变化的基本知识。 该项目应有助于加强根据北极地区特有的大气和环境条件确定降水类型的基本理论。 由于冰雪对能源预算的高度敏感性，北极地区的气候变化最为明显，因此该项目应提供对北极生态系统、物种动态和人与自然相互作用的跨学科研究尤为重要的宝贵信息。 该项目还将帮助确定北极气候变化未来可能的性质，并评估适应不断变化的条件的不同战略的可行性。 该项目由地理和空间科学计划，北极系统科学计划以及气候和大尺度动力学计划共同支持。

The type of precipitation to reach the earth's surface is highly dependent on the lower tropospheric temperature profile. Strong and persistent temperature inversions, a unique vertical profile over the Arctic during the cold season, pose unique challenges to the determination of precipitation type. In other regions, surface air temperature can be used as a predictor of this condition, but this measurement cannot be used in high-latitude locales. This collaborative research project will address some critical issues associated with precipitation type in order to better understand the spatial and temporal patterns of changes in the frequency of different precipitation types associated with increasing air temperatures over pan-Arctic land areas. The investigators will identify the atmospheric and other environmental conditions associated with each precipitation type specifically for high-latitude regions. They will use historical station records across Arctic land regions to compile the frequencies of each precipitation characteristic using various statistical analyses and mapping tools. They will analyze these data in order to enhance the capabilities for climate and hydrological model simulations of snow conditions to assess potential changes in the hydrological cycle and energy budgets. The investigators also plan to examine how much variability in precipitation type is related to short-term fluctuations in major atmospheric circulation patterns as opposed to background long-term warming trends.Project results are expected to enhance basic knowledge regarding how precipitation characteristics change in response to changing atmospheric conditions. The project should contribute to enhancement of fundamental theory regarding the determination of precipitation types based on atmospheric and environmental conditions unique to the Arctic region. Because climate change has been most evident over the Arctic due to the high sensitivity of snow and ice to the energy budget, the project should provide valuable information that is especially critical to interdisciplinary research on the Arctic ecosystem, species dynamics, and human-nature interactions. The project also will aid in efforts to determine the possible future nature of climatic change in the Arctic and to assess the viability of different strategies for adapting to changing conditions. This project is jointly supported by the Geography and Spatial Sciences Program, the Arctic System Science Program, and the Climate and Large-Scale Dynamics Program.