講演情報
[AAS14-P05]Precipitation measurement and raindrop size distribution estimation using a portable rainfall sensor
*三瓶 祐翔1、稲津 將2、小野村 史穂3、坂口 竜太1、南光 一樹4、濱田 篤5、瀬戸 心太6 (1.北海道大学理学院、2.北海道大学理学研究院、3.東京都市大学、4.東京農工大学、5.富山大学、6.長崎大学)
A newly developed, low-cost, portable, and low-maintenance rainfall sensor was evaluated through field observation at Nagasaki University, Kyushu, Japan. The observation was performed intermittently from 29 May to 14 October 2025, during which a wide range of precipitation intensities were recorded under the influence of the Baiu front and typhoon passages. The sensor recorded voltage signals reflecting microwave scattering by raindrops on the shield just above the sensor with a sampling rate of 3 kHz. It was found that the high-pass filtered output voltage was highly correlated with rainfall intensity even for an intense rainfall event exceeding 70 mm/h. Moreover, a new inversion method was developed to estimate raindrop size distributions by assuming a gamma distribution. The parameters are optimally determined to fit the statistical properties of voltage fluctuations. The estimated raindrop size distributions were generally consistent with those observed by the reference disdrometer. These results demonstrate that the portable rainfall sensor is capable of measuring even disastrous rainfall and has a potential to estimate raindrop size distributions based on a parametric model.