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

Wen Zhang, Yang Li, Xiuchen Wu, Yunhao Chen, Anping Chen, Christopher R. Schwalm, John S. Kimball

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

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 relationship between vegetation growth and SM in the dry period. The complicated interactions between vegetation phenology and hydroclimatic variations should be explicitly considered in predicting regional vegetation growth under a warmer and drier climate regime in water-stressed regions.

Original languageEnglish (US)
Article numbere2020JG005912
JournalJournal of Geophysical Research: Biogeosciences
Volume126
Issue number6
DOIs
StatePublished - Jun 2021

Keywords

  • divergent response
  • lagged response
  • soil water availability
  • spring phenology
  • vapor pressure deficit
  • vegetation growth

ASJC Scopus subject areas

  • Soil Science
  • Forestry
  • Water Science and Technology
  • Palaeontology
  • Atmospheric Science
  • Aquatic Science
  • Ecology

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