雨滴粒径分布の鉛直構造解析とレーダーによる降雨量推定手法の構築

Abstract

レーダー雨量計の地上雨量推定精度向上を根本的に解決するために, 降雨成因に依存した形で雨滴粒径分布の鉛直構造解析を基礎にしたレーダーによる地上雨量推定手法の構築を行った。構築した推定手法を実際の深山レーダー雨量計へ適用し, 現行の推定手法であるB一β法および降雨強度の高度依存性を考慮した推定手法と比較することにより, 推定精度の検証を実施した.

To improve the accuracy of the radar‐estimated rainfall, we observe and analyze the vertical profile of the rain drop size distribution (DSD) that is observed by a vertical pointing VHF Doppler radar in Japan named the MU (Middle and Upper) radar. The MU radar can detect the vertical profile of the Doppler spectrum that consists of the velocities of both the rain drop itself and air movements. One of the points of this paper is utilizing vertical profile of DSD. First, based on the obtained information, a new formulation of vertical profile of DSD related to rainfall type is developed. Secondly, an algorithm for estimating surface rainfall using radar is developed. This algorithm also considers the vertical profile of DSD related to rainfall type. Finally, this algorithm was applied into a conventional volume scanning radar named the Miyama radar operated by the Ministry of Construction of Japan.