TY - JOUR
T1 - Divergent Response of Vegetation Growth to Soil Water Availability in Dry and Wet Periods Over Central Asia
AU - Zhang, Wen
AU - Li, Yang
AU - Wu, Xiuchen
AU - Chen, Yunhao
AU - Chen, Anping
AU - Schwalm, Christopher R.
AU - Kimball, John S.
N1 - Publisher Copyright:
© 2021. The Authors.
PY - 2021/6
Y1 - 2021/6
N2 - 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.
AB - 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.
KW - divergent response
KW - lagged response
KW - soil water availability
KW - spring phenology
KW - vapor pressure deficit
KW - vegetation growth
UR - http://www.scopus.com/inward/record.url?scp=85108621923&partnerID=8YFLogxK
U2 - 10.1029/2020JG005912
DO - 10.1029/2020JG005912
M3 - Article
AN - SCOPUS:85108621923
SN - 2169-8953
VL - 126
JO - Journal of Geophysical Research: Biogeosciences
JF - Journal of Geophysical Research: Biogeosciences
IS - 6
M1 - e2020JG005912
ER -