基于GRACE的新疆平原区地下水干旱时空变化及其对气象干旱的响应

Spatiotemporal change of groundwater drought in the plain area of Xinjiang based on GRACE and its response to meteorological drought

地下水资源具有重要的资源保障和生态安全维系功能,随着全球气候变暖及人类活动强度增大,导致新疆平原区地下水资源量呈减少趋势,进一步加剧地下水干旱发生的风险。揭示新疆平原区地下水干旱时空变化特征及其对气象干旱的响应关系,对区域经济可持续发展、生态系统安全有重要意义。基于GRACE重力卫星数据和全球陆地同化系统(GLDAS)数据估算2003—2022年新疆平原区地下水储量变化,在此基础上对地下水储量变化进行标准化处理,构建地下水干旱指数,分析新疆平原区地下水干旱时空变化特征,最后使用最大相关系法分析地下水干旱对气象干旱的响应关系。结果表明:(1)新疆平原区地下水储量变化呈下降趋势,其下降速率为0.60 cm·a^(-1),下降较为明显的区域主要集中在天山区域山前平原区,上升区域主要集中在昆仑山北麓山前平原区及阿尔泰山南麓西部山前平原区。(2)地下水干旱指数监测到新疆平原区于2014年4月—2015年4月、2022年5—12月分别发生了历时13个月、8个月的地下水干旱事件。整体来看,新疆平原区地下水干旱频率为0.21,地下水平均干旱强度为1.0~2.0,地下水平均干旱历时为4~28个月;其中,平均干旱历时为4~10个月、11~16个月、17~22个月、23~28个月的面积占比分别为80.68%、9.54%、4.15%、5.63%。(3)新疆平原区地下水干旱对气象干旱的平均响应时间为18个月;响应时间为1~3个月、4~6个月、7~9个月、10~12个月、13~24个月的面积占比分别为11.00%、2.13%、2.75%、2.00%、82.12%。其中,近20 a来天山北麓山前平原区的响应时间呈增大趋势,响应时间由1~3个月增大为18~24个月,昆仑山北麓山前平原区部分区域的响应时间则先由9~12个月减缓至1~3个月,后延长至12~24个月。

Groundwater resources had an important function of safeguarding resources and maintained ecological security.As global warming and the intensity of human activities increased,the amount of groundwater resources in the plain area of Xinjiang was on a decreasing trend,further aggravaed the risk of groundwater drought.Revealing the spatiotemporal variation’s characteristics of groundwater drought in the plain area of Xinjiang and its responsed to meteorological drought was great of significance for regional economic sustainable development and ecosystem security.This article estimated the changes in groundwater storage in the plain area of Xinjiang from 2003 to 2022 based on GRACE and GLDAS data;On this basis,standardized the changes in groundwater storage and constructed a groundwater drought index;analyzed the spatiotemporal variation’s characteristics of groundwater drought in the plain area of Xinjiang.Finally,used the maximum correlation method to analyze the responsive relationship between groundwater drought and meteorological drought.(1)The change of groundwater storage in the plain area of Xinjiang showed a decreasing trend,with a decreasing rate of 0.60 cm·a^(-1),and the areas with more obvious decreases were mainly concentrated in the pre-mountain plain of the Tianshan Mountains region,while the rising areas were mainly concentrated in the pre-mountain plain of the northern foothills of the Kunlun Mountains and the pre-mountain plain of the southern foothills of the Altay Mountains.(2)Groundwater drought index monitored that there were 13 and 8 months of groundwater drought events in the plain area of Xinjiang from April 2014 to April 2015,and from May 2022 to December 2022,respectively.Overall,the frequency of groundwater drought in the plain area of Xinjiang was 0.21,the average intensity of groundwater drought was 1.0-2.0,and the average duration of groundwater drought was 4-28 months;Among them,the areas with an average drought duration of 4-10 months,11-16 months,17-22 months,and 23-28 months was 80.68%,9.54%,4.15%,and 5.63%,respectively.(3)The average responsive time of groundwater drought to meteorological drought in the plain area of Xinjiang was 18 months;the proportion of the area with responsive time of 1-3 months,4-6 months,7-9 months,10-12 months,and 13-24 months was 11.00%,2.13%,2.75%,2.00%,and 82.12%,respectively.Among them,the responsive time in the pre-mountain plain of the northern foothills of the Tianshan Mountains showed an increasing trend in the last 20 years,with the responsive time increasing from 1-3 months to 18-24 months,while the responsive time in some areas of the pre-mountain plain of the northern foothills of the Kunlun Mountains slowed down from 9-12 months to 1-3 months first,and then prolonged to 12-24 months.