[A-AS02] 高性能計算が拓く気象・気候・環境科学

[AAS02-P04] Comparing performance of tropical cyclone genesis potential indices by using a large ensemble simulation

*山田 洋平¹、宮川 知己²、中野 満寿男¹、小玉 知央¹、高須賀 大輔²、山崎 哲¹、八代 尚³、那須野 智江¹、杉 正人⁴、佐藤 正樹² (1.国立研究開発法人 海洋研究開発機構、2.東京大学　大気海洋研究所、3.国立環境研究所、4.気象庁気象研究所)

キーワード：熱帯低気圧、台風発生ポテンシャル、アンサンブルシミュレーション

Tropical cyclogenesis (TCG) is influenced by environmental conditions: the Coriolis parameter, low-level relative vorticity, ocean thermal energy, relative humidity in the mid-troposphere, atmospheric static stability and vertical wind shear (Gray 1998). Based on these environmental parameters, previous studies proposed various tropical cyclone genesis potential indices (GPIs). Recent study showed performance of GPI depends on their definition by using multi model ensemble with output CMIP6 HighResMIP (Cavicchia et al., 2023). Our previous studies showed ensemble simulation improved evaluation of performance of a GPI (Emanuel and Nolan, 2004).
In this study, we used a large ensemble simulation with a global 14-kilometer mesh Nonhydrostatic ICosahedral Model (NICAM) to evaluate the performance of four forms of GPI (Emanuel, 2010, 2022; Emanuel and Nolan, 2004; Murakami and Wang, 2022). The model was run for the boreal summer (June-October) between 2009 and 2019.
The result showed correlation coefficients between GPI and TCG differ among ensemble members for all the GPI. Focusing on the relationship between GPI and TCG on the western North Pacific, correlation coefficient is 0.41 for GPI proposed by Emanuel and Nolan (2004), -0.15 for that of Emanuel (2010), 0.84 for that of Emanuel (2022), and 0.92 for that of Murakami and Wang (2022). This suggests vertical velocity is strongly contributed to TCG on the western North Pacific.