2002-2015年西北地区陆地水储量时空变化特征

Spatial and temporal variations of terrestrial water storage in northwest China during 2002-2015

在干旱—半干旱地区,陆地水是经济社会发展的重要水源。本文利用高斯平滑滤波处理的2002—2015年逐月GRACE卫星时变重力场数据,反演了西北地区陆地水储量变化。结果表明:在时间上,西北地区陆地水储量总体呈现下降趋势,每月减少0.014 cm,相当于每年减少53.5亿m^3。在空间上,2002—2015年间陆地水储量减少区域约为224万km^2,增加区域约为106万km^2。各地区陆地水储量呈现明显的季节变化,7月达到年内最大值,陆地水储量处于盈余状态;冬、春季节为年内的低值区,陆地水储量处于亏损状态;陆地水储量的变化与降雨季节变化一致,表明西北地区降水是最重要的陆地水来源。

In arid and semi-arid regions,terrestrial water storage(TWS)is an important water resources for society.TWS in northwest China was obtained by using monthly gravity data from GRACE satellite during 2002-2015 with Gaussian filter.The results indicate that average TWS in the whole northwest China declines with time at a rate of 0.014 cm/month that is equivalent to a reduction of 5.35 billion m3 per year.Spatially,the area where TWS increases is 2.24 million km2 and the area where is decreases is 1.06 million km2.TWS varies seasonally and reaches a maximum in July when TWS is in a surplus status and reaches the lowest values during winter and spring when TWS is in a depleted status.TWS and precipitation have a similar seasonal variation,indicating precipitation is the most important water sources in northwest China.