Characteristics of rainfall kinetic energy and raindrop size distribution in subtropical zone area




Characteristics of rainfall energy and raindrop size distribution were examined in a subtropical zone area using a disdrometer. Rainfall energy values were calculated from the observations obtained from the device which measures raindrop size distributions continuously and automatically. The device however can not measure raindrops below 0.3 mm, hence rainfall energy values may give an error of about 2.48 %. Measured kinetic energy vs. rainfall intensity data showed wide distribution between the upper limit equation by Wischmeier and the lower equation by Mihara. Kinetic energy over and above the Wischmeier equation was also observed below 30 mm/h rainfall. In Ishigaki, there were large size raindrops at rainfall intensities below 30 mm/h. The distribution of raindrop size was wide from 1 mm to 5 mm in diameter compared with those measured in Tsukuba where raindrop size was concentrated between 1-2 mm.


Japan International Research Center for Agricultural Sciences Okinawa Subtropical Station


Technical A

Term of research

FY1999 (FY1995-1999)

Responsible researcher

BANZAI Kenji ( Okinawa Subtropical Station )

FUMOTO Tamon ( National Institute for Agro-Environmental Sciences )

OHWAKI Yoshinari ( National Agriculture Research Center )

SUGAHARA Kazuo ( National Institute for Agro-Environmental Sciences )

Japanese PDF

1999_15_A3_ja.pdf772.52 KB

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