Development of snowmelt runoff prediction system based on distributed snowmelt runoff model and airborne laser profiler snow depth observation

本研究的主要目的是利用新的机载激光扫描技术和我们的分布式融雪模型来预测流域内的积雪量和分布，GPS技术和激光扫描技术的进步使空间分辨率为0.5m的测量成为可能。本研究尝试在无雪季和有雪季分别用两次激光扫描获取积雪深度。从机载激光扫描仪获得的三个流域的雪深数字数据以及数字高程模型，即越后希尔赛德公园、东川流域内的八木泽流域和信浓流域内的佐栗川流域。结果表明，机载激光廓线仪是大面积积雪深度观测的有力工具。分析了积雪深度的分布特征及其与地形因子的关系 关于我们 d.为了比较激光观测的雪深，建立了一个考虑积雪自身重量粘性压缩的一维积雪模型，并将其应用到分布式融雪径流模型中。在进行比较之前，首先研究了降水调节问题。事实证明，观测到的降雪量被大大低估了。为了维持年水量平衡，需要进行水位调整和高程调整。然后将考虑这些调整的计算雪深与观测雪深进行比较。结果表明，计算的雪深分布基本上能代表观测的雪深分布，但沿着山谷线低估了雪深分布，沿着山脊线高估了雪深分布，而利用便携式激光扫描仪在小希尔赛德上进行的地面观测表明，几次降雪事件的降雪量没有显著差异。这意味着盆地内的暴风雪和局部雪崩造成的重新分布可能很重要。少

The main purpose of this study is to develop a new method to predict the amount and distribution of snow within a basin using new airborne laser scanning technology and our distributed snowmelt model.As a new technology, the progresses in GPS technology and laser scanning technology make the survey with spatial resolution of 0.5m practically available. In this study, it is tried to obtain snow depth by two laser scanning, one in snow free season and one in snow covered season. Digital data of snow depth as well as digital elevation model derived from airborne laser scanner over three river basins, namely the Echigo Hillside Park, the Yagisawa river basin within Tone river basin and the Saguri River basin within Shinano river basin. It is shown that the airborne laser profiler can be a powerful tool to make observation of the snow depth over a vast area. And also the characteristics of the distribution of the snow depth, and their relationship with many topographical factors are analyze … More d.In order to compare snow depth derived from about laser observation, an one-dimensional snowpack model talking into account of the viscous compression by the weight of the snowpack itself is developed and implemented into our distributed snowmelt runoff model. Prior to the comparison, precipitation adjustment is studied first. It turned out that the observed snowfall is significantly underestimated. In order to maintain the annual water balance, both gauge adjustment and altitudinal adjustment are necessary. The calculated snow depth considering these adjustments is then compared with the observed ones. It is shown that the calculated snow depth distribution can basically represent the observed one though it is underestimated along the valley lines and overestimated along the ridge lines.And also ground based observation by using a portable laser scanner over a small hillside slope showed no significant differences of the snowfall for several snowfall events. This implies the possible importance of re-distribution caused by blizzards and local avalanches within the basins. Less