[A-CG41] 地球惑星科学における航空機観測利用の推進

[ACG41-P02] Analysis and Forecast Using Dropsonde Data from the Inner-Core Region of Tropical Cyclone Lan (2017) Obtained during the First Aircraft Missions of T-PARCII

*伊藤 耕介¹、山田 広幸¹、山口 宗彦²、中澤 哲夫²、長浜 則夫³、清水 健作³、大東 忠保⁴、篠田 太郎⁵、坪木 和久⁵ (1.琉球大学、2.気象研究所、3.明星電気、4.防災科学技術研究所、5.名古屋大学)

キーワード：tropical cyclone、data assimilation

The inner core of Tropical Cyclone Lan was observed on 21−22 October 2017 by GPS dropsondes during the first aircraft missions of the Tropical Cyclones-Pacific Asian Research Campaign for the Improvement of Intensity Estimations/Forecasts (T-PARCII). To evaluate the impact of dropsondes on forecast skill, 12 36-h forecasts were conducted using a Japan Meteorological Agency non-hydrostatic model (JMA-NHM) with a JMANHM-based mesoscale four-dimensional data assimilation (DA) system. Track forecast skill improved over all forecast times with the assimilation of the dropsonde data. The improvement rate was 8−16% for 27−36-h forecasts. Minimum sea level pressure (Pmin) forecasts were generally degenerated (improved) for relatively short-term (long-term) forecasts by adding the dropsonde data, and maximum wind speed (Vmax) forecasts were degenerated. Some of the changes in the track and Vmax forecasts were statistically significant at the 95% confidence level. It is notable that the dropsonde-derived estimate of Pmin was closer to the realtime analysis by the Regional Specialized Meteorological Center (RSMC) Tokyo than the RSMC Tokyo best track analysis. The degeneration in intensity forecast skill due to uncertainties in the best track data is discussed.