图书馆知识库

In the winter and spring of 2009-2010 and summer of 2011, Southwestern China was hit by two severe drought events that are unprecedented over the past three decades with substantial economic damage. The understanding of how vegetation growth responds to extreme drought events in different seasons is inadequate, and underlying mechanisms are unclear. Here, we investigated the impacts of the 2009-2010 winter-spring drought and 2011 summer drought on vegetation growth and productivity in Southwestern China, using multiple remote sensing vegetation indexes including Normalized Difference Vegetation Index, Enhanced Vegetation Index, gross primary productivity/net primary productivity and vegetation optical depth. Our analyses reveal that severe soil moisture deficit in 2009-2010 winter-spring drought resulted in reduction in evapotranspiration, Enhanced Vegetation Index (0.047) and gross primary productivity (1.833 P cg) /net primary productivity in 2010 spring, worse decreased Normalized Difference Vegetation Index (0.135) and decreased vegetation optical depth in summer. By contrast, the 2011 summer drought led to enhanced vegetation greenness and higher summer gross primary productivity (1.272 P cg) /net primary productivity (0.546) compared with normal years (2007-2008), due to increased solar radiation over forests region. Our study highlights the divergent responses of vegetation to extreme drought events occurred in different seasons.