Hydrological research on snowmelt processes in both warm- and cold-climate regions

为了通过热量平衡分量阐明融雪过程，评价不同类型森林覆盖对融雪的影响，估算融雪径流量，在日本中部京都大学芦生实验林、日本东北部的山尾地区、日本东北部的小流域和不同气候条件下的样地进行了野外观测。日本北方的岩手县和日本最北部的北海道大学的茂尻实验林。用两种超声波风速计测量了感热通量的体积系数。因此，热平衡方法包括整体传输方程的潜热通量和感热通量的估计显示出良好的协议与观测到的地面融雪，蒸发或凝结从雪表面，在一个小时的时间间隔和在不同的地区。将林内的太阳辐射、蒸腾量、长波辐射、地表温度、风速、气温和相对湿度等热量平衡分量与各开放样地进行比较，并将其差值作为开放样地的比值。因此，可以根据一个点的气象观测资料，估算不同海拔高度、不同坡向、不同坡度和不同森林覆盖类型的各个山坡的融雪量。最后，通过这项研究工作，它变得非常清楚，在不同的森林覆盖率和气候条件无关的地区，在一个小时的时间间隔，在融雪季节的径流过程线可以估计。

To clarify snowmelt processes by heat balance components, to evaluate effects of various types of forest coverage on snowmelt and to estimate streamflow due to snowmelt, field observations were carried out at a small watershed and at plots in the regions with different types of climate condition, where were Ashiu Experimental Forest of Kyoto University in central Japan, Mt. Iwate in northern Japan and Moshiri Experimental Forest of Hokkaido University in the most north of Japan. Bulk coefficient of sensible heat flux were measured by two types of supper sonic wind-speed meter. Consequently, heat balance method included bulk transfer equation for the estimation of latent heat flux and sensible heat flux shows a good agreement with the observed surface snowmelt, and evaporation or condensation from snow surface, at a time interval of an hour and in various regions. All of heat balance components such as solar radiation, albedo, long-wave radiation, surface temperature, wind-speed, air temperature and relative humidity inside forest were compared with these at each open plot, and its differences were determined as the rations for the values at open plot. Therefore, snowmelt at each hill slope with different altitude, different aspect, different slope angle and different type of forest coverage can be estimated from the meteorological data observed at a point. Finally, it became very clear by this research work that the hydrographs for streamflow in snowmelt season can be estimated in the areas with different forest coverages and no relation to climate condition, at a time interval of an hour.