DEVELOPMENT OF MIDDLE ATMOSPHERE GENERAL CIRCULATION MODEL INCLUDING RADIATION PROCESSES

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A radiation scheme developed at Center for Climate System and a rediation scheme developed by Fomichev were incorporated in a middle atmosphere general circulation model at Kyushu University.The former scheme is able to treat the short wave and long wave radiations. Some test runs have been done using a tropospheric-lower stratospheric general circulation model, and it has been confirmed that the GCM can simulate a realistic circulation and temperature distribution.Fomichev's scheme is a long wave radiation scheme treating the LTE and non-LTE radiation in the middle atmosphere. In this project, we have introduced this scheme to treat the long wave radiation in the middle atmosphere and lower thermosphere. The results show that zonal wind around the mesopause becomes strong by introducing the realistic radiation process. This means that we need stronger E-P flux divergence (convergence) to close the zonal wind around the mesopause.An ozone chemical transport process was incorporated to the middle atmosphere GCM,and three dimensional ozone simulation has been conducted to investigate ozone variation in the middle atmosphere and resulting general circulation change. By making an artificial ozone hole in the Antarctic region, variations of temperature distribution and general circulation had been investigated. It is found that temperature decreases around the ozone hole, and it increases above the ozone reduction height. This result is consistent with observations. The temperature change is induced by the changes of the polar night jet, planetary wave activity, and the residual circulation induced by the ozone reduction.