A numerical simulation study of the impact of vegetation change on regional climate
Qiaoping Li (1), Yihui Ding (1)
(1) National Climate Center, CMA
By using the regional climate model (NCC/RegCM), two modeling experiments are undertaken to investigate the regional climate impact of changed vegetation over China, and results indicate that vegetation variations in large regions not only have significant local and regional effects on rainfall and air temperature, but also have far-reaching effects on the East Asian monsoon, so being one of main influence factors of the regional climate change.
Heavy desertification in north of China result in rainfall decreasing over many regions, especially in north China and northwest China, but increasing in north China and southwest China, with temperature remarkable increasing over the test region, as well as wind on lower layer enhancing, as a result, the local climate becoming more drought and unsuitable for vegetation regrowing.
On the contrary, reforestation in Northwest China tends to increase rainfall in Yellow River basin, and hence, lightening drought over there, but rainfall over Yangtze River basin and south China decrease in summer, which tends to decrease flood occurrence over there. On the other hand, local air temperature become warmer in winter and cooler in summer, with more moisture supplying to atmosphere and lower wind decreasing, thus may be reduce dust storm weather in some degree.
Furthermore, vegetation change also have obviously effects on the East Asian monsoon, including the summer monsoonal flow in east China weakening while the northwest or northeast winter monsoon enhancing after desertification over In-Mongolia. In contrast, reforestation in Northwest China result in stronger summer monsoon, with more warm and wet air transporting from south to north then make for rainfall in north China increasing, and weaker monsoon in winter can decrease occurrence of cold events.