A numerical investigation of changes in energy and carbon cycle balances under vegetation transition due to deforestation in the Asian tropical region

Temporal progress of forest reduction by deforestation in the asian tropical region was simulated using a global climate model that included a new land-surface ecosystem model. the horizontal resolution of the model was 1.875°. two experimental areas were defined: the indochina peninsula (icp) area,and the maritime continent (mtc) area. with a control simulation under the actual vegetation condition,a grassland experiment (c4 experiment) and a bare-soil experiment(bsexperiment) were carried out.forestvegetationintheexperimental areaswas gradually changed(atthe latest actualrate)to non-foresttypevegetation. the natural growth of c4 grass was reproducedinthec4experiment,and the plant growth was deterred in the bs experiment. each experiment was run for 100 model years. temporal changes of the energy and the carbon cycle balances under the vegetation transition were examined. compared with the control,the net radiation (rne) decreased because of the increase in the land surface albedo. the sensible heat flux decreased because of the decreases in rne and other particular reasons. the results for latent heat flux (e) in this study differed fromthoseinourpreviousstudy.inthec4experiment,eincreased,especially in the icp area; in the bs experiment,e decreased in both experimental areas. in the mtc area,the surface temperature in the c4 experiment increased because ofthelarge influence of decreased precipitation. decreasesofthesoil wetnessinthec4experiment were more significant in the mtc area,due to increased transpiration and the decreased precipitation. the change from forest vegetation to c4 grass vegetation induced the reduction of carbon absorption by the land surface. continuous deforestation in the asian tropical region certainly induces the elevations of the global atmospheric carbon dioxide concentrations,even if the deforested areais not replacedby bare soil surface condition. © 2011,meteorological society of japan.