利用经过高斯平滑滤波处理的2003年1月~2010年12月逐月的GRACE卫星时变重力场数据反演得到祁连山山区水储量变化,其空间分辨率为1°*1°,结合同时间段该区域35个国家气象台站逐月降水资料,采用趋势分析方法研究了祁连山山区近8 a 来的水储量时空变化特征。结果表明:祁连山山区水储量变化从空间分布上来看具有明显的空间差异性,总体表现为东少西多,南多北少的空间分布格局。在时间上,水储量变化与降水一样具有明显的季节变化规律,两者变化过程基本一致。祁连山山区平均水储量变化趋势的年内分布总体上为1~12月水储量趋势呈由高到低的递减变化。1~11月份,变化趋势为正增长,最大正增长为47.8 mm/a,出现在6月份。12月变化趋势呈负增长,负增长趋势为-2.5 mm/a。2003-2010年祁连山山区水储量总体上呈逐年上升趋势,平均上升速度为0.72 mm/mon,8 a 间水储量增加约13.6*10~8 m~3,其主要原因一方面是由于气候转暖使该区冻土退化,活动层加厚,导致蓄水增加,另一方面是由于近些年该地区加大山区水源涵养林建设,增加了山区蓄水功能。
英文摘要:
The waterstorage variations of the Qilian Mountains were recovered using GRACE monthly gravity field data,with a 1° * 1° spatial resolution and an 8- year time series length(2003- 2010). These GRACE data were smoothed by Gaussian filter before application. Meanwhile,the spatial-temporal variations of waterstorage change in the Qilian Mountains were analyzed using time trend analysis method,combining with monthly precipitation data of 35 regional meteorological stations. The results show that,on the spatial distribution,the amount of waterstorage of the Qilian Mountains is different significantly,higher in the west and the south,lower in the east and the north; as to time trend,the changes of waterstorage have obviously seasonal variation,same to the precipitation,and their changing processes keep consistent. The annual distribution of average water storage in the Qilian Mountains turns to be increasing except for Dec. The changing trends are shown as positive increase between Jan. and Nov.,with a maximum value of 47.8 mm/a in July,and negative growth in December,-2.5 mm/a. In general,the amount of waterstorage in the Qilian Mountains was increased year by year during study time period; the average growth rate is 0.72 mm/mon, increased about 13.6*10~8 m~3 totally. The main reasons are as follows:(1)permafrost degradation caused by climate warming,which makes the active layer thicker and water volume increase;(2)water resources conservation forest construction is increased yearly,which can improve water conservation function in the mountain area.