Page 116 - 水利学报2021年第52卷第2期

Spatiotemporal variation of vegetation water consumption
and its response to meteorological drought in Northwest China

1 1，2 1 1
JIANG Tianliang ，SU Xiaoling ，GUO Shengming ，WU Haijiang
（1. College of Water Resources and Architectural Engineering，Northwest A&F University，Yangling 712100，China；
2. Key Laboratory for Agricultural Soil and Water Engineering in Arid Area of
Ministry of Education，Northwest A&F University，Yangling 712100，China）

Abstract： It is of significance for ecological construction in Northwest China to assess the spatial-temporal
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change of vegetation water consumption （VWC） However， there are methodological challenges in quantify⁃
ing VWC in macroscale area. Our study proposed a method for VWC based on the Penman-Monteith formu⁃
la combined with remote sensing dataset including meteorology， hydrology， vegetation and land use change.
Boosted Regression Trees （BRT） model was used to find key factors of different VWC. Finally， the maxi⁃
mum correlation and lag time between the VWC and the self-calibrated Palmer Drought Index （scPDSI）
were analyzed. The VWC of 9 vegetations and 17 eco-geographical districts were extracted to analyze its re⁃
sponse to drought. The results show that：（1） the large scaled VWC calculation method proposed in this
paper is in good agreement with the existing research results；（2） The VWC is generally higher in the
southeast and lower in the northwest， of which 80 grids show an upward trend. The VWC in northeast >
northwest > south central > southwest during the vegetation growth period. From 1990 to 2015， the area
and the total VWC of various vegetation showed an increasing trend. The total region VWC increased by
87.62 billion m ， of which the cultivated land， woodland and grassland increased by 14.87 billion m ，
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10.80 billion m and 61.94 billion m ，respectively；（3） Potential evapotranspiration （ET 0） is the main con⁃
tributor to VWC for dry land， grassland， and standardized normalization index （NDVI） for paddy fields
and forestland. The VWD in central and western regions is higher from June to September which mainly dis⁃
tribute herbaceous，while the higher values in southeastern within November to April of next year which is
dominated by forests；（4） The VWC of grassland is more sensitive to drought， followed by woodland and
cultivated land. In addition， the comprehensive impact of drought on vegetation could characterized by
VWC better compared to NDVI. The results will provide ecological basis for combating meteorological
drought in Northwest China，and the method can provide a reference for VWD calculation on large tempo⁃
ral and spatial scale.
Keywords：vegetation water deficit quota；scPDSI；remote sensing；meteorological drought；Northwest China

（责任编辑：韩 昆）

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