Fundamental Research on Water Vapor Inflow Path into the Back-building Convective System and its Relationship with Atmospheric Stability

Abstract

In the Baiu season, heavy rainfall often occurs and has caused a lot of damage in Japan. In this research, since the supply of water vapor is essential for the back-building convective system to occur and be maintained, the water vapor inflow path to the heavy rainfall area along terrain was focused on the meso-α~β-scale. Indeed, such a water vapor inflow path can be confirmed by three-dimensional water vapor flux in this research. Moreover, since atmospheric stability which is changing due to global warming can change the flow, a hypothesis that atmospheric stability can affect the water vapor inflow stability condition was changed with the reproductive experiment. As a result, if the atmospheric condition is more stable, water vapor flux gradually becomes thinner and higher due to the stronger convergence along terrain, and the total inflow of water vapor flux is also increased slightly. In addition, the tendency that such amplifying of the water vapor flux happens under more stable conditions was confirmed in the past real cases by the clustering classification of the past cases.