Joint and relative impacts of precipitation and groundwater on
ecological drought in Northwest China: A spatiotemporal analysis using
multiple drought indices
Abstract
The increased drought risk, stemming from global warming, has
intensified ecological issues and consequently, positioned ecological
drought as a significant research topic within the field of
eco-hydrology. Nevertheless, due to limitations in the precision of
spatiotemporal data, there remains a divergence of opinions regarding
the primary water resources for vegetation growth in the northwest
region of China, whether it be precipitation or groundwater.
Consequently, this study endeavors to construct meteorological drought
index, groundwater drought index, and ecological drought index,
utilizing precipitation, groundwater storage anomaly, and ecological
water deficit, respectively. The maximum correlation coefficient and
residual analysis methods were used to analyze the joint and relative
impacts of meteorological drought and groundwater drought on ecological
drought. The primary findings can be summarized as follows: (1) The area
dominated by the joint impact of precipitation and groundwater on the
ecological drought variation accounts for about 60%, mainly distributed
in arid and semi-arid regions. (2) In spring, summer, autumn, and
winter, the average contribution of the joint impact of precipitation
and groundwater to the increase in ecological drought variation is
between 0.26 and 0.43. (3) In contrast to precipitation variation,
ecological drought induced by groundwater scarcity predominantly impacts
regions like southern Shaanxi, southeastern Gansu, and southern Qinghai.
These areas represent between 12.7% and 21.8% of the total area.