JpGU-AGU Joint Meeting 2017

Presentation information

[EE] Oral

A (Atmospheric and Hydrospheric Sciences) » A-AS Atmospheric Sciences, Meteorology & Atmospheric Environment

[A-AS06] [EE] Advances in Tropical Cyclone Research: Past, Present, and Future

Sat. May 20, 2017 1:45 PM - 3:15 PM 101 (International Conference Hall 1F)

convener:Masuo Nakano(Japan Agency for Marine-Earth Science and Technology), Akiyoshi Wada(Typhoon Research Department Meteorological Research Institute), Sachie Kanada(Nagoya University), Kosuke Ito(University of the Ryukyus), Chairperson:Masuo Nakano(Japan Agency for Marine-Earth Science and Technology), Chairperson:Akiyoshi Wada(Meteorological Research Institute)

2:15 PM - 2:30 PM

[AAS06-09] Global cloud-permitting simulations of Typhoon Fengshen (2008)

*Tomoe Nasuno1, Hiroyuki Yamada2, Masuo Nakano1, Hisayuki Kubota3, Masahiro Sawada4, Ryuji Yoshida5 (1.Japan Agency for Marine-Earth Science and Technology, 2.Faculty of Science, University of the Ryukyus, 3.Atmosphere and Ocean Research Institute, The University of Tokyo, 4.Meteorological Research Institute, 5.RIKEN, Advanced Institute for Computational Science)

Keywords:Tropical cyclogenesis, global nonhydrostatic model, cloud-permitting simulation

Large-scale fields and inner-core processes relevant to the formation and intensification of Typhoon Fengshen (2008) were examined by simulations using Nonhydrostatic Icosahedral Atmospheric Model (NICAM; Satoh et al. 2014) with a cloud-permitting (3.5-km mesh) resolution (Nasuno et al. 2016). Fengshen was formed in mid-June during the onset of the WNP monsoon and the active phase of a boreal summer intraseasonal oscillation (BSISO) event. The TC genesis was preceded by the formation of a lower tropospheric large-scale gyre associated with enhanced equatorial westerlies and a middle tropospheric wave trough intruding above the gyre.
To understand the impact of atmospheric conditions and the convective effects on the TC environment and precursor disturbance, five simulations were performed by varying the initial data (interpolated using ECMWF YOTC or NCEP FNL analysis) and cloud microphysics settings.
In three simulations initialized using the ECMWF YOTC, a middle tropospheric trough developed within a few days following a large-scale latent heat release, which enabled the successive occurrence of deep convective events within the 50-km radius of the incipient disturbance and subsequent TC formation. In the run with weaker latent heating in the lower troposphere, the trough was weak and TC formation was significantly delayed.
In the run initialized using the NCEP FNL, where the latent heat release averaged over the entre simulation was the same as its ECMWF YOTC counterpart, neither the trough nor a TC developed, lacking the collocation between the latent heat release and large-scale gyre in the early period. Under the vertical wind shear increasing poleward, it was critical for the incipient vortex to experience upward penetration before it moved farther northward.
These results indicate that the superposition of large-scale disturbances in the lower and middle troposphere and their linkage through convective enhancement played an important role in the genesis of Fengshen by preconditioning the establishment of a deep upright inner core. Another implication is that the modeled TC genesis is sensitive to difference in initial environment under a strong vertical shear like in this case.

Nasuno, T., Yamada, H., Nakano, M., Kubota, H., Yoshida, R., 2016: Global cloud-permitting simulations of Typhoon Fengshen (2008), Geoscience Letters, 3, 32, DOI: 10.1186/s40562-016-0064-1.
Satoh, M., and others, 2014: The Non-hydrostatic Icosahedral Atmospheric Model: Description and Development. Progress in Earth and Planetary Science, 1, 18. doi:10.1186/s40645-014-0018-1.