How Has Land Cover Change Affected Precipitation for the Mongolian Plateau Since 2001?

Abstract:

Recent trends towards increased grazing pressures on the Mongolian Plateau have placed a premium on grasslands to meet increasing domestic and international demand for animal products. Recent land cover shifts include degradation in ecosystem function and structure of the grasslands, reduction of vegetation cover, particularly in northeastern Inner Mongolia, and urban expansion around Ulanbaatar. Here we examine the impacts of land cover change using the Regional Atmospheric Modeling System (RAMS v. 6.0) to test whether or not the land cover changes from 2001-2010 could significantly impact surface energy fluxes enough to alter convection over the regions where grasslands are dominant. We performed this experiment for two distinct sets of boundary conditions: the growing season of 2001 (a drought/dzud year) and 2003 (a wet year). Preliminary results from the model indicate increased cloud cover and lowered daily temperature ranges for the northeastern Mongolian Plateau accompanying patterns of meadow and forest steppe growth. More broadly, the overall trend towards reduced vegetation cover leads to higher screen height temperatures and reduced soil moisture throughout much of the domain, together with a shift of moisture southward of Inner Mongolia. In the desert steppe regions around the Gobi desert, more complex patterns associated with land degradation will be discussed.