[A-AS02] 台風研究の新展開～過去・現在・未来

[AAS02-02] Two-day Consecutive Typhoon Aircraft Observations Capturing Development and Phase Transition to an Extratropical Cyclone

*金田 幸恵¹、坪木 和久¹、加藤 雅也¹、平野 創一朗²、辻野 智紀³、山口 宗彦³ (1.名古屋大学宇宙地球環境研究所、2.京都大学、3.気象研究所)

キーワード：熱帯低気圧、航空機観測、ドロップゾンデ、台風

Tropical cyclones (TCs) are hazardous weather systems. With recent increase in sea surface temperature (SST) in a higher-latitude, understanding how a TC develops in midlatitude is important because TC activity intensifies over warmer sea. Our 5-min interval observations by novel meteorological sondes launched from an aircraft flying at an altitude of 13,000 m for two consecutive days captured a TC development in warming mid-latitude and rapid structural changes due to the northern baroclinic zone over steeply decreasing SST. On October 9, over warm sea, Typhoon Barijat (2024) near 30^oN developed a group of tall, vigorous, and upright meso-gamma convection commonly termed the vortical hot tower (VHT) in northeastern side near the storm center. The VHT with positive vorticity developed to the tropopause, warming and moistening the deep layers. On October 10, in contrast, a cold and dry mid-level descending jet intruded from the west crossing the storm core-region. Our vertically high-resolution 5-min interval observations indicated that the descending jet enhanced mid-to-low level warm core by adiabatic heating, however, it eroded the VTH and led the TC to transit to an extratropical cyclone.