Hydrological study of snowmelt flooding during a rain-on-snow event

为了阐明雨雪过程中融雪洪水的产生机制，在北海道北部的莫什里雪水文站进行了2011-2013年三个融雪季的积雪表面降雨模拟实验。在2012年的实验中(积雪深度：170 cm)，积雪开始浇水后50~90分钟开始从积雪底部流出，总流出量为46~48 L，总浇水量为120~170 L。然后，事实证明，雨下雪事件期间积雪中的渗水在仅融雪或弱降雨事件中表现出不同的径流过程。

In order to clarify the generation mechanism of snowmelt flooding during the rain-on-snow event, rain simulation experiments over the snow surface were made in the three snowmelt seasons from 2011 to 2013 at the Moshiri snow hydrologic observatory, northern Hokkaido. In the experiment in 2012 (snow depth: 170 cm), the outflow from the bottom of snowpack began in 50 to 90 minutes after a watering start, and the total outflow was 46 to 48 L to the total watering amount of 120 to 170 L. When inflow and outflow rates were in a steady state, the rate of watering rain contained in outflow water was estimated 60 to 70 % using the water and the deuterium mass balance equations. Then, it turned out that percolating water within a snowpack during the rain-on-snow event showed a different runoff process during the snowmelt-only or weak rainfall event.