Collaborative Research: GPS-based terrestrial water storage anomalies during hydrologic extremes: linking hydrologic process, solid-earth response, and monitoring networks

合作研究：极端水文期间基于 GPS 的陆地水储存异常：将水文过程、固体地球响应和监测网络联系起来

• 批准号: 1521127
• 负责人: Adrian Borsa
• 金额: $ 20.44万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1521127&HistoricalAwards=false
• 关键词: Collaborative; Research; GPS; based; terrestrial

Terrestrial water storage (TWS) is the total amount of water stored as soil moisture, groundwater, snow, in surface water bodies, and in the biosphere. Variations in TWS reflect the watershed-scale response to changes, such as drought and groundwater pumping. Observations of TWS are needed to study the water cycle and its role on the Earth, but existing tools for monitoring TWS variations are not satisfactory. Recently, global positioning system (GPS) observations of the height of the land surface have been used to quantify TWS variations. However, errors in TWS estimated from GPS data have not been quantified. This research has three components to study how GPS observations can be used to monitor TWS. First, the resolution and accuracy of TWS variations estimated from GPS land surface heights will be quantified by combining hydrologic data and a model of how the Earth deforms. Second, GPS data from several thousand stations will be used to estimate TWS variations across the continental United States for the past decade and forward in time. Third, a comparison will be made between existing TWS estimates and estimates based on GPS observations. The expected outcomes of this project will advance the start-of-the-art in TWS monitoring by evaluating the magnitude and sources of errors in GPS-based TWS data. This is a necessary step towards applying these data to a range of wide hydrologic applications, including estimates of soil water volumes and groundwater recharge, the effects of drought, and subsidence caused by changes in groundwater storage. Observations of TWS anomalies are critical for understanding how the hydrologic cycle responds to forcing such as drought. Existing tools for monitoring TWS anomalies are not optimal for many hydrologic applications. Recently, GPS observations of land surface vertical displacement have been used in novel ways to quantify the spatial and temporal variations of TWS anomalies associated with groundwater mining, seasonal snowpack, and drought. These results suggest that GPS-based records of displacement could greatly enhance monitoring of the terrestrial water cycle. However, none of the studies to date have quantified the errors in TWS anomalies estimated from GPS observations. The research plan has three components designed to assess how GPS observations can best be used to monitor TWS. First, the resolution and accuracy of TWS anomalies estimated from GPS vertical position data will be quantified by combining hydrologic loading data and models of the Earth's elastic response. Second, vertical position data from several thousand stations will be used to estimate TWS anomalies and associated errors across the continental United States, retrospectively for the past decade and forward in time. Third, a comparison will be made between existing TWS anomaly products and the product based on GPS positions. Differences will be related to hydrologic processes through analyses of in situ hydrologic observations of groundwater, soil moisture, and snow water equivalent. The expected outcomes of this project will advance the start-of-the-art in TWS monitoring by evaluating how errors in GPS-based TWS anomalies are related to interactions between hydrologic process, the solid earth response, and the monitoring network at the continental scale. This is a necessary step towards applying these data to a range of hydrologic applications.

陆生储水（TWS）是存储的水量，作为土壤水分，地下水，雪，地表水体和生物圈中的总量。 TWS的变化反映了流域规模对变化的反应，例如干旱和地下水泵送。需要观察TWS来研究水周期及其在地球上的作用，但是现有的监测TWS变化的工具并不令人满意。最近，全球定位系统（GPS）对土地表面高度的观察已用于量化TWS变化。但是，从GPS数据估计的TWS中的错误尚未量化。这项研究具有三个组成部分，可以研究如何使用GPS观测来监测TWS。首先，通过将水文数据和地球变形方式的模型结合来量化TWS变化的分辨率和准确性。其次，在过去的十年中，将使用来自数千个站点的GPS数据来估计美国大陆的TWS变化。第三，根据GPS观察，将进行现有TWS估计值和估计值的比较。该项目的预期结果将通过评估基于GPS的TWS数据中错误的幅度和错误来推进TWS监视的开始。这是将这些数据应用于一系列广泛的水文应用的必要步骤，包括估计土壤水量和地下水补给，干旱的影响以及由地下水储存变化引起的沉降。 对TWS异常的观察对于理解水文周期如何应对干旱等响应至关重要。现有用于监视TWS异常的工具对于许多水文应用并不是最佳的。最近，对土地表面垂直位移的观察结果已被新颖的方式使用，以量化与地下水采矿，季节性积雪和干旱相关的TWS异常的空间和时间变化。这些结果表明，基于GPS的位移记录可以极大地增强对陆地水周期的监测。但是，迄今为止，没有一项研究量化了从GPS观测值估计的TWS异常中的错误。该研究计划的三个组件旨在评估如何最好地使用GPS观测来监测TWS。首先，通过将水文载荷数据和地球弹性响应的模型相结合，可以量化从GPS垂直位置数据估计的TWS异常的分辨率和准确性。其次，将使用数千个站点的垂直位置数据来估算整个美国大陆的TWS异常和相关的错误，这是在过去的十年中回顾性的。第三，将根据GPS位置进行现有TWS异常产品和产品之间的比较。通过分析地下水，土壤水分和雪水等效物的原位水文观测，差异将与水文过程有关。该项目的预期结果将通过评估基于GPS的TWS异常中的错误与水文过程，固体地球响应和大陆尺度的监视网络之间的相互作用有关，可以通过评估TWS监视的开始。这是将这些数据应用于一系列水文应用的必要步骤。