Water, Drought and Snowpack Monitoring in the United States Using the EarthScope Plate Boundary Observatory GPS Network

含水层、土壤、湖泊和冰川中的水储存量变化导致地球发生弹性变形，其方式可以用全球定位系统（GPS）检测到。我们建议在地球镜的GPS站研究这种与水有关的变形？的板块边界天文台（PBO），并使用这些观测来估计美国大陆的水负荷的变化。鉴于水和干旱在西部的长期重要性，以及气候变化对整个美国水安全的威胁，改善水循环的直接监测具有重大的社会和经济意义。通过提供关于水储存和水循环的新数据，这项工作有可能对美国的水管理产生重大和积极的影响，这项工作的目标是将联合收割机全球定位系统的负荷估计与美国宇航局的GRACE卫星使命的质量变化估计以及有关水文系统及其边界的独立信息结合起来，以开发改进的水模型再分配这项研究特别强调了对内华达州和落基山脉的所有重要的积雪估计，以及干旱对加州地下水变化的影响？美国的中央谷和其他主要含水层。具体而言，在未来三年内，我们将：1）重新处理所有每日GPS位置数据，以生成可靠的季节性和非季节性位移序列; 2）校正所有时间序列的偏移，瞬态位移和已知的大气/海洋负荷; 3）反演美国大陆的时空水负荷; 4）用GRACE使命的低分辨率数据限制GPS质量变化，以更好地估计水通量; 5）调查脆弱的山区积雪和地下水含水层系统的质量变化，以应对当前美国西部的干旱;（5）将这项工作的结果作为一套数据产品和相应的方法公布，供科学家使用，并供水管理人员在可能的情况下实际使用。

Changes in water storage in aquifers, soils, lakes and glaciers cause the Earth to deform elastically in ways that can be detected using the Global Positioning System (GPS). We propose to study this water- related deformation at GPS stations in EarthScope?s Plate Boundary Observatory (PBO) and use these observations to estimate the variation of water loads over the continental United States. Given the longstanding importance of water and drought in the West, and the threat of climate change to water security across the entire USA, improvements in direct monitoring of the water cycle are of great social and economic relevance. By providing new data on water storage and the water cycle, this work has the potential to make a significant and positive impact on water management in the United States, in addition to improving the underlying science.The goal of this work is to combine GPS load estimates with mass change estimates from NASA's GRACE satellite mission and independent information about hydrological systems and their boundaries to develop improved models for water redistribution. This study puts special emphasis on the all- important snowpack estimates for the Sierra Nevada and Rocky Mountains, and drought impacts on groundwater changes in California?s Central Valley and other principal aquifers in the USA. Specifically, over the next three years, we will: 1) reprocess all daily GPS position data to generate reliable series of seasonal and nonseasonal displacements; 2) correct all time series for offsets, transient displacements, and known atmospheric/oceanic loads; 3) invert for the spatiotemporal water loading across the continental USA; 4) constrain GPS mass changes with lower-resolution data from the GRACE mission to develop better estimates of water fluxes; 5) investigate mass changes of vulnerable mountain snowpack and groundwater aquifer systems in response to the current western USA drought; and 5) publish the results of this work as a set of data products and accompanying methodology for use by scientists and for possible operational use by water managers.