WEAK RESPONSE OF VEGETATION PHOTOSYNTHESIS TO METEOROLOGICAL DROUGHTS IN
SOUTHWEST CHINA: INSIGHTS FROM GOME-2 SOLAR-INDUCED FLUORESCENCE
Drought stress threatens vegetation dynamics across diverse ecosystems.
Monitoring how vegetation responds to water stress is vital for
ecological conservation. The response of vegetation photosynthesis to
water availability variations in Southwest China from 2008 to 2018 is
investigated in this study. The solar-induced fluorescence (SIF) derived
from GOME-2 is used to characterize photosynthetic changes. We examined
the sensitivity of SIF anomaly to standardized
precipitation-evapotranspiration index (SPEI) at multiple time scales to
evaluate the drought impacts on different ecosystems (i.e. forests,
croplands, grasslands, and shrublands). We find that (1) SIF has
significant yet weak correlations to SPEI across major ecosystems in
Southwest China; (2) Forests are more sensitive to short-term droughts
in comparison with other ecosystems. (3) Cropland, grassland, and
shrubland are more subjected to long-term droughts compared to forests.
Our findings indicate that, in Southwest China, satellite SIF may not be
effective in monitoring the impact of drought on vegetation due to its
weak response to SPEI. The robustness of using satellite-observed SIF to
assess drought’s effects still needs to be further tested with
high-resolution SIF data.