ON THE GENERAL CIRCULATION AND BAROTROPIC ENERGETICS AT 500 MB LEAVEL DURING JANUARY 1977

January 1977 was unusual cold throughout the mid-latitude continental region in the Northern Hemisphere. By using 500 mb level daily data of the January, the general circulation and barotropic energetics were investigated. Based on the study of 500 mb level circulation, it was pointed out that the cold January might be related to the following aspects:(1)There was often a high pressure over the polar cap, and the ridge in Alaska was very strong and steady. (2) The u-momentum transport from high latitudes to middle latitudes for the January was so abnormally large that anomalous east wind occured in high latitudes. (3) The monthly averaged basic air current was approximately the barotropic instable condition which was measured by the meridional gradient of absolute vorticity. The nonlinear wave-zonal and wave-wave exchanges of kinetic energy for the January was measured over the latitude belt from 17.5°N to 77.5°N.The monthly averaged values of these quantities were compared with the normal ones. According to the analysis of barotropic energetics it was shown that the severe cold January might be related to the following aspects: (1)n=3 wave kinetic energy was excessively strong. (2) The outbreak of severe cold wave was most closely associated with 3 wave development. (3) Wave of wave number 3 received much more energy from n=2 wave through wave-wave interaction. (4) The mag-nitude of energy transporting from n=2 wave to all other waves for the January was about twice as much as the normal one. The interrelationship of the above phenomena was discussed.