*M.M. Gavin Dayanga Madakumbura^1,2、Satoshi Watanabe²、Masahiro Tanoue²、Yukiko Imada³、Yukiko Hirabayashi² (1.Department of Civil Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. 、2.Institute of Engineering Innovation, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan. 、3.Meteorological Research Institute, Japan Meteorological Agency, 1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan.)