西北地区地下水干旱时空演变趋势及对气象干旱的动态响应

Spatio-temporal evolution trend of groundwater drought and its dynamic response to meteorological drought in Northwest China

为分析西北地区地下水干旱时空演变趋势及对气象干旱的动态响应,利用GRACE和GLDAS数据定量评估地下水储量变化,构建地下水干旱指数GRACE-GDI分析地下水干旱的时空演变特征,并利用Pearson相关系数分析了地下水干旱对气象干旱的动态响应关系。结果表明:西北地区地下水储量总体上以0.25 cm/a的速率枯竭;河西走廊、六盘山区、青海南部地下水干旱发生频率较高,陕南地区、柴达木盆地地下水干旱发生频率较低,西北地区多年平均地下水干旱面积比例为29.0%;地下水干旱与气象干旱的响应关系存在明显的空间异质性,其中呈显著正相关关系的区域占59.3%,且由于气候变暖和植被改善,在准噶尔盆地、吐鲁番盆地、青海湖流域、阿尔泰山等地区响应程度增加;干旱响应时间主要为1~6月和19~24月。

To analyze the spatio-temporal evolution trend of groundwater drought and its dynamic response to meteorological drought in Northwest China(NWC), the groundwater storage change was quantitatively evaluated by GRACE and GLDAS data and the groundwater drought index GRACE-GDI was constructed to analyze the spatio-temporal evolution characteristics of groundwater drought. The Pearson correlation coefficient was used to analyze the dynamic response relationship of groundwater drought with meteorological drought. The results show that the groundwater storage in NWC generally decreased at the rate of 0.25 cm/a. The frequency of groundwater drought in the Hexi Corridor, Liupan Mountains and southern Qinghai was relatively high, while in southern Shaanxi and the Qaidam Basin was relatively low. The average annual groundwater drought area in NWC was 29.0%. There existed obvious spatial heterogeneity in the response relationship between groundwater drought and meteorological drought with 59.3% of the area having a significant positive correlation. The response degree increased in the Junggar Basin, Turpan Basin, Qinghai Lake Basin and Altai Mountain due to the climate warming and improved vegetation. The drought response time in NWC mainly ranged from 1 to 6 and 19 to 24 months.