地表面フラックスが降水分布に及ぼす影響に関する基礎的解析

Abstract

One of the keys in modelling hydrologic processes is scaling-up and scaling-down of hydrologic models.In such studies, it is necessary to comprehend simple processes systematically.Another problem related to the above is how to include "conditions of field", such as topography, vegitation, soil, and so on.One the part of receiving such conditions, hydrologic models are needed to be described so that the surface processes and atmospheric processes may interact each others.Considering the above points, this study suggests the first step of studying long term interactions between precipitation and soil moiture by investigating effects of water vapour flux from ground surface on rainfall distribution.In this study, a one-dimensional cumulus cloud model and a warm rain model are introduced into an atmospheric model, and the water vapor is assumed to be supplied from a certain area of the ground surface.Water vapour flux from ground is found out to affect the distribution of precipitation through 3 points (1) release of latent heat, (2) advection, and (3) convergence of horizontal wind.Distribution of water vapour flux from ground and amount of horizontal water vapour influx make defferences in total amount of precipitation, size and location of precipitation areas.