Selection of the winter representative precipitation station within a basin

The shape of Japan is a narrow island and stretches from southwest to northeast. In winter, the wind blows from northeast to southeast. The humid wind which absorbs the high humidity while passing the Sea of Japan, which it releases as snow as it encounters the high mountains.Here we discuss the case where there is some amount of snowfall in the southern part of the topographic divide. We can estimate the depth of spring runoff from the depth of winter accumulated snow at selected station.We estimated a ‘model’ representing the shape of the land where there is a valley in the northern part, intervening the topographic divide, and a small river basin in the southern part.In the model, a good correlation can be found between the depth of winter accumulated precipitation at the selected station and the depth of runoff at the dam site.