AN INTERANNUAL VARIATION OF ATMOSPHERIC FRONTS AND SURROUNDING ATMOSPHERIC CONDITIONS FROM MAY TO JULY DURING RAINY SEASON IN SOUTH-WESTERN JAPAN

Abstract

 The projection of variation of rainfall associated with atmospheric fronts in the future climate is critical because torrential rainfall disasters bring structures and livelihood damage all over Japan. In order to investigate the contribution of atmospheric fronts to rainfall, this study found that heavy rainfall disasters occurred when fronts were stagnant in south-western Japan for more than eight days during rainy season from 2006 to 2020. The detection of fronts by physical index is a useful numerical method for identifying the fronts in future climate, and it is important to verify the method. By comparing the detected front using the F diagnostic from atmospheric data and the front depicted on weather maps, it is shown that the physical index used in the F diagnostic increases with the development of an extratropical cyclone with the front.