Increasing Winter Runoff in a Middle-Latitude Mountain Area of Central Japan

Abstract

Meteorological and hydrological data were analysed, over 37 years during the period from 1965 to 2001, recorded by the Kurobe Dam meteorological observatory, which is located in a nature-reserved mountainous area within a heavy-snowfall region of central Japan. The analysis demonstrated that both winter runoff and air temperature increased significantly during this period. The interannual variation of winter runoff was governed not only by precipitation, but also by air temperature. The significant increasing trends in air temperature were also found at the adjacent JMA meteorological stations, showing a high correlation with air temperature observed by the Kurobe Dam.