Using RegCM3 To Quantitatively Study How Does The Change Of Wetland Area Affects The Climate In Three River Sources Area

In this paper, changes of climate and wetland in Three River Sources Region in recent years was analyzed. Using RegCM3 model to study how does the change of wetland area affects the climate in Three river sources area. Through adjusting the parameterized scheme of the underlying surface covering with the meteorological model, mainly the wetland area change, simulate its meteorological effect. Discuss the interactional result between the change of marsh area and climate.The trend of primary climatic factor such as temperature, rainfall, etc in Three river sources area nearly 40 years was analysed. The result shows: the temperature rise widely, and the elevatory degree in winter and autumn is higher than in spring and summer. The change of rainfall has a large spacial difference, there is a decrease trend in eastern, the western is opposite. Take the three source consideration, the source of the yellow river take on the warm and dry trend, the source of Changjiang River and Lantsang is warm and wet.Nearly 15 years(1990-2004) numerical integral experiment is used to the Three river sources area using RegCM3 regional climatic model, focus on the simulative ability of the model to the temperature and precipitation. The result indicates: RegCM3 model has the ability to simulate the distributing character of precipitation and temperature in Three river sources area. The model simulate the annual change of temperature suitably, the result between simulative number and actual number is closer, but the model need to improve on the annual change of precipitation and numeric simulation. As the mean while the author also do the surface sensitive experiment on the underlying surface , the result shows: after changing the characteristic of underlying surface and the vegetation parameter, both temperature and precipitation simulative result has an obvious change, that is to say the model is sensitive to the change of underlying surface.Simulate 18 weather stations' climate of Three river sources in 1980 and 2000 using RegCM3 model, focus on the variational rule of temperature, rainfall and temperature difference at month. The result indicate: there is an opposite change between wetland area and temperature, namely when the wetland area decrease, the regional temperature rise, the "Cold—humid ecological effects" is weaken in wetland area; whereas, when the marsh area rise, the regional temperature decrease, the "Cold—humid ecological effects " is intensified. The variational direction of temperature and wetland area is opposited. The vatiational trend of rainfall and marsh area is similar, namely when the wetland area decrease, the rainfall decrease; on the contrary, if the rainfall decrease, the wetland will decrease. The variational direction of monthly temperature range and wetland area is opposite, that is to say, after the marsh area decrease, the monthly temperature range has the rising trend in Three river sources.Simulate the climate change using RegCM3 model through the actual underlying surface in 1980 and 2000. After analyse the rule of temperature, rainfall and temperature difference in a month in 18 different meteorological sites, the result shows: when wetland area descend, the regional temperature increase, the rainfall decrease, the month temperature difference will increase. This trend is obviously in western area.The study of this dissertation shows: The ascending trend of temperature nearly 40 years in Three river sources area result in the wetland area decreased directly. The simulative result of climatic model show: the marsh area decreasing result in the regional temperature increased. If the rainfall decrease, the water source of marsh area will decrease and this will bring on the degenerate wetland area. When the marsh area decrease, the rainfall will decrease, this phenomena show the marsh area has the "Cold—humid ecological effects ". As a result of the two negative feedback above, the large degenerate of marsh area would weaken the "Cold—humid ecological effects" of wetland area.