Regional Climate Impact Assessment of Vegetation Change in Loess Plateau: Combining WRF-NOAH Model and Long Time Series Satellite Observations

Loess Plateau (LP), a pilot region with arid and semi-arid climate in China, has undergone significant vegetation change since the launch of the 'Gain for Green' Program (GGP) in 1999. As the aim to increase forest cover and control soil erosion, parts of agriculture land have converted to forests and grassland. The net warming or cooling effect of afforestation in this region is still uncertain, depending on the competing contributions of albedo and evapotranspiration as well as background climate. Further, it is reported that vegetation change has altered the rainfall distribution and frequency in LP.

With the availability of decades of satellite observations, the transition of land cover types and change of vegetation status can be represented realistically. Through incorporating this information into the static field of coupled atmosphere-land regional climate model, it is expected to quantify the biophysical climate effects due to vegetation change.

The objective of this study is to investigate how surface air temperature and precipitation response to afforestation due to government policy in LP, combining multiple long time series satellite products from 1982 to 2016 and WRF-Noah model. To highlight the effect of GGP and avoid sensors calibration issue, the whole temporal range is divided into two periods: 1982-1999 and 2000-2016. Sensitivity experiments has been conducted through model simulation using dynamic real vegetation observations (EXPR) and static vegetation observations (CTRL).