Contemporary Variability, Future Changes and Human Dimensions of Snowpack Water Resources Over the Western United States

一个研究小组将结合数据分析、遥感、建模和全球变化的人类维度的技能，对美国西部地区在当前和未来可能的气候状态下的积雪水资源的变异性和可持续性进行综合评估。重点将放在科罗拉多和哥伦比亚盆地及其子盆地。将使用混合数据集评估当代变率，这些数据集包括每日雪水当量（SWE）、来自SNOTEL（雪遥测）站点和天气报告站的温度和降水记录，以及来自被动微波亮度温度的SWE。结合国家气象中心（NMC）的大气场“再分析”，我们将首先重点建立环流与季节性积雪积累/融化之间的大尺度和区域关系。随后将分析观测记录中的极端事件以及SWE变率与远相关模式之间的联系，强调对厄尔尼诺-南方涛动（ENSO）强迫的区域响应。这些调查还将利用NMC的中期预报（MRF）模式的一个版本的集合预报，该模式由观测到的和理想化的海面温度演变所迫。我们的经验和建模研究利用了环流的“降尺度”，即点或区域变量（例如，SNOTEL站点对子盆地的平均SWE）通过与基于主成分分析的大气环流模式的频率/持久性的经验关系与环流相关。在对当代变率的研究之后，环流降尺度传递函数将应用于至少两种不同的一般环流模式（GCMs）的2xCO2输出。该技术充分利用了当前的gcm，通过使用大尺度环流提供气候变化情景，模式可以很好地再现大尺度环流，同时避免了模拟的点面变量的不确定性。在类似于上述诊断研究之后，将从2 × co2情景中重建的日温度、SWE和降水与融雪径流模型相结合，在一系列区域研究中评估融雪径流的潜在未来变化。利用上述调查所得的信息以及其他现有数据，将审查科罗拉多和哥伦比亚盆地不同的水管理系统，因为它们与SWE的季节性和国际变化以及全球变化条件有关。目的是改进对城乡结合部水资源管理最相关的时间和空间尺度的预测，以及对了解水文变异性的适当预测。这些研究将侧重于：1)用户间水资源分配的灵活性，以应对年际变率和水资源可用性的潜在变化；2)系统产出（农业、娱乐、电力、水质）对可能出现的极端气候变化、气候事件序列和气候变化的脆弱性。

9634329 Serreze A research team combining skills in data analysis, remote sensing, modeling and the human dimensions of global change will conduct an integrated assessment of the variability and sustainability of snowpack water resources over the western United States under contemporary and possible future climate states. Emphasis will be placed on the Colorado and Columbia basins and sub-basins. Contemporary variability will be assessed using blended data sets incorporating daily snow water equivalent (SWE), temperature and precipitation records from SNOTEL (SNOwTELemetry) sites and synoptic reporting stations as well as SWE derived from passive microwave brightness temperatures. In conjunction with National Meteorological Center (NMC) 'reanalysis' atmospheric fields, we will first focus on establishing large-scale and regional relationships between circulation and the seasonal accumulation/melt of the snowpack. This will be followed by analyses of extremes in the observed record and linkages between SWE variability and teleconnection patterns, emphasizing regional responses to El-Nino Southern Oscillation (ENSO) forcings. These investigations will also utilize ensemble forecasts from a version of NMC's Medium Range Forecast (MRF) model, forced by observed and idealized evolutions of sea surface temperature. Our empirical and modeling studies make use of circulation 'downscaling', whereby point or regional variables (e.g., SWE from SNOTEL sites average for sub-basins) are related to circulation through empirical relationships with the frequency/persistence of atmospheric circulation patterns based on principal component analyses. Following studies of contemporary variability, the circulation downscaling transfer functions will be applied to 2xCO2 output from at least two different general circulation models (GCMs). This technique makes the best use of today's GCMs to provide climate change scenarios through use of the large-scale circulation, which the models reproduce fairly well, while avoiding the uncertainties modeled point surface variables. Following diagnostic studies similar to those outlined above, reconstructed daily temperature, SWE and precipitation from the 2xCO2 scenarios will be coupled with a snowmelt runoff model, providing assessment of potential future changes in snowmelt runoff in a series of regional studies. Using information from the above investigations along with other existing data, different systems of water administration in the Colorado and Columbia basins will be examined as they relate to seasonal to international variations in SWE and conditions of global change. The objective is to improve predictions on the time and space scales most relevant to the management of waters resources at urban-rural interfaces and those appropriate to understanding hydrologic variability. These studies will focus on: 1) flexibility of water allocation among users in response to interannual variability and potential changes in water availability and 2) vulnerability of system outputs (agriculture, recreation, power, water quality) to possible extremes of climate variations, sequences of climate events and climate change.