利用GRACE时变重力场反演黑河流域水储量变化

Water Storage Variations in Heihe River Basin Recovered from GRACE Temporal Gravity Field

黑河流域水储量变化对该区域的生态环境和经济建设等具有重要影响。本文利用2002-08—2011-06的GRACE(gravity recovery and climate experiment)时变重力场模型GRGS-EIGEN-GL04,采用去相关滤波P3M6与300km高斯滤波相结合的滤波方法反演了黑河流域陆地水储量变化,扣除GLDAS(global land data assimilation system)水文模型计算的土壤水和冰雪变化,给出了黑河流域地下水储量的时空变化,并利用张掖地区23口地下水测井数据对地下水反演结果进行了初步验证。研究结果表明:①黑河流域陆地水储量整体上呈现减少趋势,与该流域气候变化和CPC(Climate Prediction Center)水文模型的计算结果具有较好的一致性,其减少速率为2.3cm/a等效水高;②黑河流域地下水储量呈现长期减少趋势,其减少速率为2.5cm/a等效水高,上、中游区域地下水储量减少速率相当,下游区域地下水储量减少速率明显小于中上游区域。

The water storage variation in Heihe River basin is very important to the ecological environment and economic construction. Based on a hybrid filtering scheme of the decorrelated filter P3M6 and 300 km Gaussian filter, the terrestrial water storage variations in Heihe River basin are recovered from the GRACE （gravity recovery and climate experiment） temporal gravity field models GRGS-EIGEN-GL04 for the period from April 2004 until June 2011. By removing the soil moisture and snow mass changes derived from the global hydrological model GLDAS （global land data assimilation system）, the groundwater storage variations in space-time domain are obtained in Heihe River basin, and preliminarily confirmed by the groundwater observations from 23 monitoring wells in Zhangye city. Two conclusions can be drawn from theresults：① the terrestrial water storage variations tend to reduce with the average rate of 2. 3 cm/a in terms of equivalent water height （EWH）, consistent with the regional climate changes and the results from the global hydrological mode CPC （Climate Prediction Center）;②The groundwater storage variations show the same tendency at the average loss rate of 2.5 cm/a EWH. While the regional groundwater storage rates are different, the average loss rates in upstream and midstream areas are almost the same, but obviously larger than that of downstream area of Heihe River Basin.