THE NUMERICAL-SIMULATION OF THE CLIMATIC-CHANGE CAUSED BY CO2 DOUBLING

The IAP two-level atmospheric general circulation model was coupled to a 60-m-deep mixed layer ocean model and a zero-layer thermodynamic mo del to simulate the climatic effects induced by a doubling of CO2 conc entration in the atmosphere. The global surface temperature is 1.75-de grees-C when CO2 is doubled. This value is lower than most of other re sults in the world, such as those of GFDL, NCAR, UKMO, GISS and OSU mo dels. There are large regional and seasonal differences in the climati c change. Great warming is found in the Northern Hemisphere's high-lat itude region and the Antarctica; and the warming in land areas is grea ter than in ocean areas, while the precipitation increases in high lat itudes and tropical regions but decreases in subtropical regions. In b oth hemispheres, the warming is greater in winter than in other season s. As for the changes in China, we find that the precipitation in sout hwestern and northern China greatly decreases in summer but increases in winter.