Energy balance in 40-50 day periodic oscillation over the Asian summer monsoon region during the 1979 summer

Abstract

Based on calculations of data from FGGE Level III b, a discussion is made of the energy balance in the 40–50 day periodic oscillation over the Asian monsoon region during the 1979 summer. It is found that the main source of 40–50 day periodic perturbation is the monsoon region extending from central South Asia to Southeast Asia. In the upper layer over the North Pacific subtropical area (10-20°N, 150°E-150°W) pressure work turns into kinetic energy that maintains 40–50 day periodic perturbation associated with the variation in position and intensity of the mid-Pacific trough. The mean energy budget in the three-dimensional space (0-30°N, 30°E-150°W, 100-1000 hPa) indicates that the 40–50 day periodic perturbation transports kinetic energy to a seasonal mean and a transient perturbation wind field.