Assessing Global Water Storage Variability from GRACE: Trends, Seasonal Cycle, Subseasonal Anomalies and Extremes.
Assessing Global Water Storage Variability from GRACE: Trends, Seasonal Cycle, Subseasonal Anomalies and Extremes.
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DOI：
10.1007/s10712-016-9367-1
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发表时间：
2016
影响因子：
4.6
通讯作者：
Seneviratne SI
中科院分区：
文献类型：
--
作者：
Humphrey V;Gudmundsson L;Seneviratne SI
在过去的十年中，重力恢复和气候实验（GRACE）对陆地水储存的全球变化提供了前所未有的看法。虽然越来越多的案例研究为区域分析提供了丰富的概述，但仍然缺乏对GRACE变异性主要特征的全球评估。为了解决这个问题，我们调查的时间变化的GRACE记录的主要特征分解成线性趋势，年际，季节性和亚季节性（年内）组件的网格化的时间序列的月等效水高度。我们提供了这些组件的相对重要性和全球空间分布的概述。与降水和温度的相关分析表明，年际和亚季节异常都与大气强迫的波动密切相关。作为一个新奇的，我们表明，对于世界上的大区域的高频异常的每月GRACE信号，这已被部分解释为噪声，可以统计重建从每日降水量，一旦一个足够的平均滤波器应用。该过滤器将降水对任何给定月份（包括较早的降水）的存储变化的时间衰减贡献进行积分。最后，我们还调查极端干旱异常的GRACE记录，并将它们与记录的干旱事件。这一全球评估将区域研究置于更广泛的背景下，并揭示了迄今为止尚未记录的现象。
Throughout the past decade, the Gravity Recovery and Climate Experiment (GRACE) has given an unprecedented view on global variations in terrestrial water storage. While an increasing number of case studies have provided a rich overview on regional analyses, a global assessment on the dominant features of GRACE variability is still lacking. To address this, we survey key features of temporal variability in the GRACE record by decomposing gridded time series of monthly equivalent water height into linear trends, inter-annual, seasonal, and subseasonal (intra-annual) components. We provide an overview of the relative importance and spatial distribution of these components globally. A correlation analysis with precipitation and temperature reveals that both the inter-annual and subseasonal anomalies are tightly related to fluctuations in the atmospheric forcing. As a novelty, we show that for large regions of the world high-frequency anomalies in the monthly GRACE signal, which have been partly interpreted as noise, can be statistically reconstructed from daily precipitation once an adequate averaging filter is applied. This filter integrates the temporally decaying contribution of precipitation to the storage changes in any given month, including earlier precipitation. Finally, we also survey extreme dry anomalies in the GRACE record and relate them to documented drought events. This global assessment sets regional studies in a broader context and reveals phenomena that had not been documented so far.