南方7省市陆地水储量动态变化主控因素研究

Investigation of the Main Controlling Factors of TWSA Variation in Seven Provinces of South China

近年来,全球气候变化和人为活动日益剧烈,研究陆地水储量动态变化的影响因素,有助于深入了解陆地水储量的时空分布规律,为区域水资源管理和保护提供依据。基于(Gravity Recovery And Climate Experiment)GRACE数据及8种气候要素,采用趋势分析、互相关分析和偏最小二乘回归(Partial least squares regression,PLSR)等,从网格尺度(1o×1o)上分析我国云南、贵州、四川、广西、湖南、湖北以及重庆7省市陆地水储量距平(Terrestrial Water Storage Anomaly,TWSA)变化趋势及其不同时间尺度下的主要影响因素。结果表明:2002-2017年期间,我国南方7省市除西部区域外TWSA总体上呈现明显增长的趋势,在重庆、贵州、湖北和湖南省交界处上升幅度最大,平均增幅最大可达每年0.9 cm,该区域TWSA动态变化由长期趋势主导。云南、四川中南部、广西南部以及湖南湖北二省的东部区域中,TWSA随时间变化由季节周期性变化所主导。月尺度下,TWSA与空气比湿的动态变化最为相似,85%网格TWSA的变化受气候波动控制,仅研究区中北部TWSA明显受到大型水库消峰填谷调控的影响,其季节波动弱于其他地区,但水库对该区域TWSA年尺度的变化影响明显减弱。年尺度下,全区域TWSA的变化仍主要受气候因素的影响,陆地水储量60%以上的变化可由气候变化解释,降雨为七成以上研究区域TWSA年尺度变化的主控要素,仅三峡水库附近TWSA受到人为活动和气候变化的共同影响。

In recent years,global climate change and human activities have become increasingly severe.Studying the influencing factors of the dynamic changes of terrestrial water storage can help to deeply understand the temporal and spatial distribution of terrestrial water storage,and provide a basis for regional water resources management and protection.Based on(Gravity Recovery and Climate Experiment)GRACE data and eight climatic factors,this paper uses the trend analysis,cross-correlation analysis and(Partial least squares regression)PLSR model to analyze the(Terrestrial Water Storage Anomaly,TWSA)variation trends and the influencing factors in the South area of China(Yunnan,Guizhou,Sichuan,Guangxi,Hunan,Hubei and Chongqing)from the grid scale(1°×1°).The results show that,from 2002 to 2017,the TWSA in most study area,except the western region,exhibited a significant growth trend.The highest increase rate reaches 0.9 cm/year in the junction area of four provinces(Chongqin,Guizhou,Hunan and Hubei)where the dominant pattern of TWSA variation in this region is guided by the long-term and seasonal trends.In Yunnan,central and southern Sichuan,southern Guangxi,and the eastern of Hunan and Hubei provinces,the dominant pattern of TWSA changes over time is seasonal variation.At the monthly scale,the TWSA dynamic is closest to the air specific humidity.85%of the grid TWSA changes can be explained by climate fluctuations.The central and northern parts of the study area are significantly affected by the regulation of large reservoirs.In other areas,the influence of reservoirs on the annualscale changes of TWSA in this area is not significant.At the annual scale,the change of TWSA in the whole region is still mainly affected by climatic factors.More than 60%of the change in terrestrial water storage can be explained by climate change,and rainfall is the main controlling factor for the annual change of TWSA in more than 70%of the study area.Only the vicinity of the Three Gorges Reservoir TWSA is still affected by a combination of anthropogenic activities and climate change.