[A-CG54] Promotion of climate and earth system sciences using manned/unmanned aircrafts

[ACG54-05] Evaluation of newly developed dropsonde for aircraft observation

*Sachie Kanada¹, Masaya Kato¹, Kazuhisa Tsuboki¹, Tadayasu Ohigashi⁴, Soichiro Hirano², Kensaku Shimizu³, Risa Yanagihara³, Asuka Yoshimura¹, Yusuke Goto¹, Kanna Tsukagoshi¹ (1.Nagoya University, 2.Kyoto University, 3.Meisei Electric Co. Ltd., 4.National Research Institute for Earth Science and Disaster Resilience)

Keywords:Typhoon, Aircraft observation, Dropsonde, Verification

To explore the dynamic and thermodynamic structure and intensification process of intense typhoons by aircraft observation, the Tropical cyclones–Pacific Asian Research Campaign for the Improvement of Intensity estimations/forecasts (T-PARCII) has been conducted since 2017 (Ito et al. 2018; Yamada et al. 2021). For this purpose, a novel dropsonde, the iMDS-17, has been developed by Nagoya University and Meisei Electric Co., Ltd.. The dropsonde was designed to be launched from an aircraft flying at an altitude of 13,000 m and ground speed of 720 km h^-1. Owing to their light weight of approximately 130 g, parachutes are not necessary when observing upper-air atmospheric conditions throughout the troposphere. Approximately the same technology as that of the Japan Meteorological Agency (JMA) operational radiosonde (iMS-100) was used, except that the pressure was measured directly using a pressure sensor. To evaluate the performance of the iMDS-17, intercomparison experiments were conducted on 27 and 28 March 2024 on the southern island of Japan using a balloon-borne shooter system. The dropsonde and radiosonde were lifted by the same balloon and released at altitudes between 9,000 and 13,000 m. Comparison between data obtained from the experiments confirmed the adequate performance of iMDS-17 in temperature and wind observations; maximum differences between the dropsonde and radiosonde were less than 1 K and 2 m s^-1 in temperature and wind, respectively, in most altitudes between 9-2 km. Meanwhile, a dry bias was identified for humidity, particularly in moist layers. The causes of the dry bias are discussed.
(Kanada et al. 2024, SOLA)