陆地水储量(TWS)是气候变化的重要指示,研究TWS有助于理解气候变化是如何影响水资源的循环。本文用GRACE重力卫星数据与气象资料恢复了2002 2016年我国陆地水储量的时空分布变化,运用M-K趋势分析判断陆地水储量与气候数据的趋势,并将具有显著趋势的地域划分为10个关键区域,其中:松花江流域、长江中下游流域、珠江流域、三江源自然保护区及青藏高原中部TWS趋于增加(2.76 7.14 mm · a~(-1)),而华北平原、黄土高原、辽河流域、天山山脉及雅鲁藏布江流域陆地水储量趋于减少(-1.47 -8.93 mm · a~(-1))。TWS与气候数据、气候环流指数的Spearman相关性的结果表明:TWS的变化主要受气候变化影响,气候变化是造成陆地水储量变化的主要因素,但在人口密集区域,人类活动对TWS的影响也不可忽视,如华北平原过度汲取地下水是造成TWS减少的重要原因。
英文摘要:
Background, aim, and scope The gravity satellite represented by GRACE in recent years has shown a unique advantage in the detection of terrestrial water storage (TWS). Until 2002, the implementation of the GRACE gravity satellite program makes it possible to obtain the information of the mass distribution of the earth system with high precision, and the application of the gravity satellite detection technology in hydrometeorology is greatly promoted. Materials and methods This paper adopts the product data from August 2002 to July 2016 released by the Space Research Center of the University of Texas. The product data are filtered by Gauss with a smooth radius of 500 km, and the strip errors of the north and south are removed from the monthly data. At the same time, various tidal effects and non-tidal atmospheric and oceanic effects are removed. The trends of TWS, temperature and precipitation are studied by using M-K trend, and the temporal and spatial variations are shown by ArcGIS. Results The results show that the TWS of Songhua River Basin, Middle and Lower Reaches of Yangtze River, Pearl River Basin, Sanjiangyuan Nature Reserve and Central Tibetan Plateau tend to increase, while North China Plain, Loess Plateau, Liaohe River Basin, Tianshan Mountains and Yaluzangbu River Basin tend to decrease. Four densely populated areas are selected in the critical area to analyze the relationship between TWS and climate circulation index. The TWS of four regions can be considered to be affected more severely by human activities, showing a positive correlation between the climate circulation factors and TWS. Discussion The reason for the change of TWS is complex, which is the result of the interaction between climate change and human activities. It is a huge challenge to divide the change of TWS into natural or human factors in detail. There has been no previous study on the natural and human factors for the change of terrestrial water storage in China. The changes of water storage in China are mainly affected by climate change, but the impact of human activities on TWS is also extremely profound, especially in irrigated areas, human activities may be an important reason for the decrease of TWS. Conclusions The TWS in the Middle and Lower Reaches of Yangtze River, Pearl River Basin, Sanjiangyuan Nature Reserve and the Yaluzangbu River Basin are mainly affected by climate change, while North China Plain may be more affected by human activities. Human activities also have a positive effect on the increase of TWS, such as water transfer projects across river basins, which can improve the spatial distribution of water resources. The establishment of nature reserves also has a positive effect on the increase of TWS. In addition, even though human intervention is intense, climate change has always been a major factor in TWS. Recommendations and perspectives It is a great challenge to distinguish the impact of natural and human factors on TWS, and it is difficult to quantify and analyze the effects of natural and human factors in a precise way, and to use climate data as auxiliary data. It is very valuable to judge the influence of climate change on TWS change, especially the climatic circulation index is used to study the change factors of TWS for the first time in this paper, future research should focus on the use of hydrological models and statistical methods to explore the real causes of terrestrial water storage change.