Snowfall estimates using snowfall phenomena under the lower-atmosphere area

为了估计降雪量(降雪稀有)，我们测量了雪粒从雪云落到地面附近的降雪过程。研究结果如下：1.研究结果。电磁波反射回波在垂直方向的测量在富山国立理工学院的电气楼屋顶安装了一台小型雷达(微雨雷达，由METEK公司制造)，观测到了从春季到秋季的降雨现象，并测量了降雨率。从2002年12月开始连续观测冬季降雪现象，利用电子天平分析了电磁波反射回波与降雪率的关系。从雷达反射因子上观察到，在每个高度都有下降现象。利用α和ε得到的功率谱近似于伽马分布函数，并在这些参数中对降雪类型进行了分类。利用图像处理技术测量降雪粒子的形状和质量通过落在观测塔中的降雪粒子观察到图像。测量雪粒密度是可能的。根据雪粒直径与风速的关系，可以对雪粒的种类(冰雹和雪花)进行分类。雷达降雪率测量系统根据1和2之间的关系，可以利用这两个雷达参数来计算降雪率和估计降水种类。我们将这些测量数据和分析结果集成到数据库中，编制了降雪量估算因子。该技术不仅对降雪进行定量观测，而且对固体降水的种类和质量进行测量也是非常有用的。

To estimate amount of snowfall (snowfall rare), we measured the snowfall process that snow particles fall near the ground from the snow cloud. The results were given as follows.1. Measurement of the electromagnetic wave reflection echo in the vertical directionIt installed a small radar (Micro rain radar, made from METEK) in Toyama National College of Technology, the electric building rooftop.It observed a rainfall phenomenon from the spring to the fall and rainfall rate were measured. The winter snowfall phenomenon was continuously observed from December, 2002.We analyzed the relation between the electromagnetic wave reflection echo and the snowfall rate using an electronic balance. It was observed a falling phenomenon from the radar reflection factor in every altitude. The power spectrum was approximate at the gamma-distribution function using α and ε and it classified a snowfall pattern in these parameters.2. Measurement the shape and the quality of a snowfall particle by the image processing techniqueIt observed an image by the snowfall particle which falls in the observation tower. It was possible to measure the density of snow particle. It becomes able to classify of the snow particle kind (hail and snowflake) from the relation between the diameter and the velocity.3. Snowfall rate measurement system by the radarForm the relation between 1 and 2, it was possible to calculate the snowfall rate and estimate the kind of precipitation using the two radar parameter. We integrated these measurement data and an analysis result into the data-base and prepared a snowfall estimate factor. This proposed technique is not only useful to observe snowfall quantitatively, but also to measure the kind and quality of solid precipitation.