SNOWMELT RUNOFF ANALYSIS TAKING INTO ACCOUNT SEASONALITY OF TEMPERATURE LAPSE RATE FOR UPPER AND MIDDLE AREA IN SHINANO RIVER BASIN

Abstract

 Predicting snowmelt runoff with a high accuracy is important in water utilization and prevention of floods. Temperature lapse rate is one of uncertainty in snowmelt runoff analysis. In this study, we estimated temperature lapse rate in each month of each year in two regions and assessed seasonality and locality of temperature lapse rate. The purpose of this study is that we showed the importance of considering of temperature lapse rate in snowmelt runoff analysis to compared snowmelt runoff analysis which using estimated temperature lapse rate and snowmelt runoff analysis which using constant temperature lapse rate in four large and small regions in upper and middle area in Shinano river basin. As a result, temperature lapse rate has seasonality and locality. Using estimated temperature lapse rate led to high accuracy in snowmelt runoff analysis. Additionally, regions having large amount of snowfall were affected by temperature lapse rate than regions having small amount of snowfall in a heavy snowfall region.