Potential Impacts of Land-Use on Climate Variability and Extremes

This study aims at exploring potential impacts of land-use vegetation change (LUC) on regional climate variability and extremes. Results from a pair of Australian Bureau of Meteorology Research Centre (BMRC) climate model 54-yr (1949--2002) integrations have been analysed. In the model experiments, two vegetation datasets are used, with one representing current vegetation coverage in China and the other approximating its potential coverage without human intervention. The model results show potential impacts of LUC on climate variability and extremes. There are statistically significant changes of surface interannual climate variability simulated by the model. Using different vegetation datasets, significant changes in correlation coefficients between tropical Pacific Ni\~no3.4 SST and precipitation and surface temperature over East Asia are identified, which indicate that changes in vegetation coverage may alter ENSO impacts on regional climate variability. Because of the lack of slowly varying surface processes when forests are removed and less rainfall is received following LUC, the ENSO signal simulated by the model becomes stronger. Results furthermore show that land-use could modulate characteristics of decadal variations in this region. When using current vegetation coverage, the model gives better simulation of observed climate variations in the region than the case using potential vegetation coverage. In addition, results suggest that land-use could be a potential factor contributing to the prolonged drought in central-west China. Changes in local climate extremes, including precipitation and surface temperature maxima and minima, are also identified. Overall, this study has illustrated the importance of further investigation of such important issues in future land-use studies.