Investigations of vegetation-atmosphere feedback in China using satellite-based FPAR data

Satellite-based fraction of PAR (Photosynthetically Active Radiation) absorbed by vegetation canopy and monthly climatology data (1982-2000) are used to investigate possible feedbacks between surface air temperature, precipitation and vegetation. The results show that correlation in spring and summer with FPAR leading temperature for one month is negative in most regions of China, which may indicate the more prosper the vegetation is, the more positive influence the vegetation may have on lowering local temperature. The instantaneous correlation between temperature and FPAR is more promising in spring and autumn. The positive correlation with summer precipitation leading FPAR for one month shows the possible positive impact of precipitation on vegetation. The feedback parameter between FPAR and temperature is all positive on the south of Yangtze River Basin (up to 0.5 degrees C (0.1FPAR)(-1)) and is negative on the north of 30 degrees N latitude (up to -0.42 degrees C (0.1FPAR)(-1)). The spatial distribution of feedback parameter between FPAR and precipitation is not homogeneous. The feedback parameter is also varying with different vegetation types and different seasons. The feedback parameters should be a nice basis of vegetation-atmosphere feedback for dynamic vegetation model validation.