Divergent Response of Vegetation Growth to Soil Water Availability in Dry and Wet Periods Over Central Asia

作者：Wen Zhang, Yang Li, Xiuchen Wu, Yunhao Chen, Anping Chen, Christopher R. Schwalm, John S. Kimball · 发表于：Journal of Geophysical Research Biogeosciences · 年份：2021 · DOI：10.1029/2020jg005912 · 被引用次数：41 · 研究领域：Plant Water Relations and Carbon Dynamics、Tree-ring climate responses、Remote Sensing in Agriculture

Abstract Vegetation growth is interactively controlled by hydrothermal conditions and the associated biophysiological changes. These factors have experienced dramatic changes over the past decades in Central Asia, where vegetation growth is primarily constrained by soil water availability. However, we have limited understanding of the time scales and the underlying drivers for the responses of vegetation growth to variations in soil water availability between wet and dry periods. Here, we explored the response of vegetation growth to decadal‐scale hydroclimatic variations in wet versus dry periods, during 1992–2015, using remote sensing retrievals of normalized difference vegetation index and multiple climate factors. We discovered divergent responses of vegetation growth to soil water availability, measured by soil moisture content (SM), between wet and dry periods, with spatiotemporally intensified correlation to SM in the dry period. We revealed a unanimous 1‐month time lag in the response of vegetation growth to SM in the dry period, contrary to much longer time lags and a more spatially heterogeneous response in the wet period. The divergent vegetation responses to SM can be largely explained by the variations in hydroclimatic conditions and spring phenology. The intensified vegetation growth‐SM response in the dry period was strongly associated with increased temperature and vapor pressure deficit. Earlier spring phenology exerts a crucial role in mediating the relation...