近20年黄河源区陆地水储量增加及其可能原因分析

Increase in Terrestrial Water Storage and Possible Causes over the Source Region of the Yellow River in Recent Two Decades

黄河源区陆地水储量对黄河流域生态保护与高质量发展国家重大战略的实施起到至关重要作用。利用长短期记忆(LSTM)网络模型,基于GRACE和GRACE-FO重力卫星产品与GLDAS产品分析了黄河源区2002年4月至2020年3月的陆地水储量变化特征,并探讨了降水和蒸散发对陆地水储量变化的影响。结果表明:LSTM模型可用于重建GRACE与GRACE-FO产品之间的数据缺失,其在验证期的皮尔逊相关系数为0.923、纳什效率系数为0.816。此外,GRACE产品具有好的准确性,与GLDAS数据的皮尔逊相关系数为0.737。黄河源区陆地水储量呈现先增加后降低再增加的变化趋势,整体上有着明显的增加趋势。相对地下水和雪水当量,土壤水的增加是陆地水储量增加的主要贡献成分。降水量增加是黄河源区陆地水储量增加的重要原因,而蒸散发量下降是源区陆地水储量上升的可能原因。

Terrestrial water storage in the source region of the Yellow River plays an important role in the ecological protection and high-quality development of the Yellow River Basin,which is a part of the implementation of the national major strategy.Based on GRACE and GRACE-FO gravity satellite products and GLDAS product,this paper utilizes long short-term memory(LSTM)network model and analyzes the variation characteristics of terrestrial water storage in the source region of the Yellow River from April 2002 to March 2020,and investigates the influences of precipitation and evapotranspiration on the changes in terrestrial water storage.Results indicate that the LSTM model can be used to reconstruct the data gap between GRACE and GRACE-FO products with Pearson correlation coefficient of 0.923 and Nash efficiency coefficient of 0.816 at the test period.In addition,the terrestrial water storage data from GRACE has a good reliability,and against GLDAS data with the Pearson correlation coefficient of 0.73.The terrestrial water storage has a variation trend of first increasing,then decreasing and then increasing,and an apparently increasing trend in the source region of the Yellow River integrally.Compared with groundwater and snow water equivalent,the increase in soil moisture makes the major contribution to the increase in terrestrial water storage.The precipitation increasing is the significant reason for the increase in terrestrial water storage in the source region of the Yellow River,and the evapotranspiration decreasing is the possible reason.