Basic Study on the Characteristics of Energy and Water fluxes in the Alpine Region and Satellite Remote Sensing of Snow

本文通过野外观测，研究了高山地区和低海拔地区雪面热量收支的差异。在富士山北方坡海拔2950 m和3400 m处以及新泻县海拔300 m处的三个观测点测量了雪面能量交换。通过每周一次的雪采样器测量的雪密度和每六小时一次的相机测量的融化深度来计算融雪。湍流热通量的作用在高山区比在低海拔地区更重要。在高山地区，潜热通量通常为负值，而当潜热通量为正值时，伴随着暖湿大风，有时会导致积雪融化，微波遥感技术为积雪制图提供了重要的优势：全天候的能力和直接探测雪水当量的可能性。然而，影响雪微波特征的因素很多，如雪的粒径、液态水含量、密度和层结等。介电常数的分布代表了雪的主要特性。利用便携式介电探头对积雪进行了野外测量，建立了积雪介电常数模型。并将该模型应用于现有雪坑观测资料，识别了两个地区介电常数剖面的时空分布。

This study investugates the discrepancies of heat budgets on snow surface between in the high alpine area and in the lower-lands through the field observations. The energy exchanges across the snow surface were measured at three observation sites ; two were located at the diffrent elevations, 2950m and 3400m, on the northern slope of Mt.Fuji and the other at 300m in Niigata prefecture. Snowmelt was calculated using snow density measured by snow sampler once a week and melting depth by camera in every six hours. The role of turbulent hear flux in high alpine area was more important than in the lower-land. The latent heat flux was usually negative and the large positive latent heat flux associated with the warm, humid and strong wind sometimes caused the very intense snowmelt in the high alpine area.Microwave remote sensing techniques offer important advatages for snow mapping : the all weather capability and the possibility to detect snow water equivalent directly. However there are many factors which influence on the microwave signature of snow such as grain size, liquid water content, density and stratification. The profile of dielectric constant represents the major snow properties. The dielectric constant model was established based on the field measurements of snow using the portable dielectric probe. Furtermore the temporal and spatial distributions of the profile of the dielectric constant in two regions were identified by applying the model to the exsiting snow pit observation data.