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)

3:00 PM - 3:15 PM

[AAS06-12] Doppler radar analysis of intensity and inner-core structure of Typhoon Haiyan (2013) near landfall

*Udai Shimada1, Hisayuki KUBOTA2, Hiroyuki Yamada3, Esperanza Cayanan4, Flaviana Hilario4 (1.Meteorological Research Institute, 2.Atmosphere and Ocean Research Institute, The University of Tokyo, 3.University of the Ryukyus, 4.Philippine Atmospheric, Geophysical and Astronomical Services Administration)

Keywords:tropical cyclone, Doppler radar

Intensity and inner-core structure of the second most intense tropical cyclone in the world since 1979, Typhoon Haiyan (2013), were examined using ground-based Doppler radar data observed by the Guiuan radar over about 2.5 h immediately before landfall on Leyte Island in the Philippines. The wind fields of Haiyan from 2- to 6-km altitude were retrieved by the ground-based velocity track display (GBVTD) technique from the Doppler velocity data. The GBVTD-retrieved maximum wind speed reached up to 101 m s-1 at 4-km altitude on the right side of the track. A relatively fast moving speed of Haiyan, about 11 m s–1, largely contributed to the increase in the maximum wind speed. Azimuthal mean tangential wind increased with height from 2- to 5-km and a local maximum lay at 5-km altitude with a value of 86 m s–1. The central pressure was estimated at 908 hPa with uncertainty of ±5 hPa by using the GBVTD-retrieved tangential wind and by assuming the gradient wind balance. The radius of maximum radar reflectivity was located at about 23-km radius from the center, a few kilometers inside the radius of maximum wind. The reflectivity structure was highly asymmetric at 3-km altitude and above, and was almost axisymmetric below 3-km altitude in the presence of relatively weak vertical shear (~4 m s–1). The axis of the eyewall ring tilted to the downshear direction. In addition, vortex precession with a period of about 75 min was analyzed.