[A-AS02] From weather predictability to controllability

[AAS02-P07] Relationship between Typhoon Faxai (2019) and environmental fields

*Misaki Hishinuma^1,2, Tomoe Nasuno^2,3, Fudeyasu Hironori^1,3, Yohei Yamada², Chihiro Kodama², Masuo Nakano² (1.Yokohama National University, 2.Japan Agency for Marine-Earth Science and Technology, 3.Typhoon Science and Technology Research Center, Yokohama National University)

Keywords:typhoon, environmental fields

In a Moonshot Goal 8 project, the possibility of typhoon control for a safe and prosperous society is being studied. One important theme in this typhoon research is to quantitatively understand how typhoons affect the environmental field. Studies on the relationship between typhoons and large-scale atmospheric fields using observational data have shown the systematic relationship between typhoons and the Pacific High. However, the effect of typhoons on the environmental field is seasonally dependent, and it is desirable to understand their relationship using a large number of samples under similar conditions. In this study, we investigate the relationship between typhoon intensity and large-scale atmospheric fields focusing on a Typhoon Faxai case in 2019, taking an advantage of large member ensemble simulations using a global nonhydrostatic model NICAM. Faxai made landfall in Japan on 8 September 2019 and made significant damages. We extracted the Faxai-like vortices from the large ensemble simulation dataset. Among the Faxai-like vortices, we selected tracks passing near Japan (138°E-143°E, 40°N) and divided them into two groups: (1) wind speeds of 40 m/s or higher when passing near Japan (strong), and (2) wind speeds of less than 25 m/s when passing near Japan and less than 25 m/s at the time of lifetime maximum wind speed (weak). Composite analysis of dynamical fields, precipitation, and precipitable water was performed. Preliminary analysis indicates clear differences between the two groups in the horizontal distribution of precipitation and precipitable water. This is suggestive of systematic relationship between the intensity of Faxai and water vapor transport. In addition, the area where the precipitation differences were large roughly corresponded to the track of Typhoon Lingling, which coexisted with Faxai in the real atmosphere. These results suggest a possibility that Faxai may have affected the rate of Lingling's weakening or that the two typhoons interacted with each other during their development. Further investigation of the relationship between the two typhoons and the large-scale atmospheric fields is under way.