Recent hiatus of Tibetan Plateau vegetation greening and the consequence impact on climate

The remote sensing products showed significant vegetation greening during 1980-2010 under the “warm-humid” climate changes over the Tibetan Plateau. Several previous studies showed such significant increasing of vegetation NDVI  and LAI resulted an overall cooling effects on climate over the Tibetan Plateau. Our field survey in 2008 and 2018 at 36 alpine grassland sites showed that aboveground biomass increased for legumes and forbs, but decreased for grasses and sedges, resulting in no overall change in the aboveground biomass during the 10-year period. Such hiatus of Tibetan Plateau vegetation greening was also found in three remote sensing products (GLASS, Globmap, GIMMS). We run WRF4.0 model to quantify the recent vegetation impact on climate during 2008-2018 and found the recent hiatus of Tibetan Plateau vegetation greening mainly showed warming effects due to the increasing of the daily minimum air temperature. Such warming effects also increased of the active layer depth and annual thawed fraction over the seasonal permafrost regions. Although the latent heat flux was also increased, the increasing water vapor showed insignificant impact on precipitation except on the cumulus precipitation in Fall.