利用GRACE(gravity recovery and climate experiment)重力卫星数据反演20032015年间华北平原地下水储量变化,并在此基础上利用经验正交函数(empirical orthogonal function,EOF)分析方法对结果进行了时空特征分析。研究表明,华北平原地下水储量变化可以分解为3个主要模态,其对总体变化的解释率达到96.35%。其中,第1模态解释率约为80%,空间变化一致,表现出多年趋势性减少与年内季节性变化相结合的特征,推测可能由研究区内地下水开采和年内降水分布共同作用导致;第2和第3模态分别表现出东北西南和西北东南2种变化相反的空间格局,对总体变化的解释率分别约为12%和5%,在时间上没有明显的趋势性变化,推测可能主要受沿海-内陆、山前-平原的水循环和水文地质条件控制。研究有助于进一步了解华北平原地下水储量变化的时空特征与驱动机制。
英文摘要:
GWSA (groundwater storage anomaly) data of North China Plain from 2003 to 2015 were estimated from terrestrial water storage change (TWSC ) data retrieved by monthly GRACE (gravity recovery and climate experiment) . The EOF (empirical orthogonal function) method was applied to analyzing the GWSA,and it is shown that cumulative contribution rate of the first three EOF modes reached up to 96.35%. The explanation rate of the total variance of first mode reached about 80%. It is shown that GWSA in the North China Plain behaved consistently descending in the whole region with obvious seasonal fluctuations,caused by groundwater exploitation and precipitation. The second and third mode,with an explanation rate of about 12% and 5%,showed that spatial pattern in northeast - southwest direction and that in northwest - southeast direction were obviously opposite. However,no significant temporal diversification was found,presumably mainly controlled by water cycle under the coastal - inland,piedmont - plain and hydrogeological conditions. This study helps to further understand the spatiotemporal characteristics and drive mechanism of groundwater change in North China Plain.