Estimation of the Tangential Winds and Asymmetric Structures in Typhoon Inner Core Region Using Himawari‐8

Abstract

Observations of the winds in tropical cyclones are still limited. We propose a new method for deriving the tangential winds in tropical cyclones, which employs a spectral analysis of high‐frequency cloud imaging by latest‐generation geostationary meteorological satellites such as Himawari‐8. The method was applied to the visible images of boundary layer clouds in the eye of Typhoon Lan (2017) over an 8.5‐hr period. The low‐level tangential winds over the central two thirds of the eye in radius were close to a rigid body rotation and increased with time. On its outside was a region with striating clouds rotating at much higher angular velocities, which may have been supergradient. Asymmetric motions were visualized as the deviation from the inner rotation, and the vorticity of some mesovortices were quantified. These asymmetric motions are suggested to transport angular momentum to accelerate the inner rotation.

Revisiting the Characteristics of Super Typhoon Saola (2023) Using GPM, Himawari-9 and FY-4B Satellite Data

“…Li et al [38] developed a blended method for radar reflectivity based on the Himawari-8 meteorological satellite and S-band dual-polarization weather radar data, and applied them to the observation and analysis of Super Typhoon In-fa in 2021. Tsukada and Horinouchi [39] proposed a method for deriving the tangential winds in tropical cyclones by employing high-frequency cloud imaging from Himawari-8. Tsujino et al [40] presented a quantitative estimation of inner-core wind fields based on 2.5 min temporal resolution images from Himawari-8 and clarified the dynamics of the inner eyewall decaying of Typhoon Trami in 2018.…”

Sea Surface Wind Structure in the Outer Region of Tropical Cyclones Observed by Wave Gliders

“…Wind structure can be measured by satellites, for example, synthetic aperture radar (SAR) (Mouche et al, 2017(Mouche et al, , 2019Yu et al, 2019) and imager (Cordoba et al, 2017;Tsujino et al, 2021;Tsukada & Horinouchi, 2020;Zheng et al, 2019), and estimated by satellite altimeter-derived ocean parameters (Sharoni et al, 2021). However, all remote sensing observations have certain extent of bias due to, for example, the observational error of TC rain (Sharoni et al, 2021) or the limited number of satellites that are suitable for TC observations (Mouche et al, 2017;Yu et al, 2019).…”

“…However, wind vectors on the right side observed at a fixed station exhibit a clockwise rotation, while in the Southern Hemisphere the rotation turns to anti‐clockwise (Price, 1981). The TC wind field is usually asymmetric (Liu et al., 2007; Tsukada & Horinouchi, 2020) with stronger wind on the right‐hand side along the track. Wind inflow is shown to vary both radially and azimuthally within a TC.…”

Variation Trends of Asymmetrical Precipitable Water Vapor Outside the Tropical Cyclone Center Over the WNP and WSP Ocean

“…To improve the TC prediction performance and reduce the TC‐induced damage (Williams, 2019; X. Zhang et al., 2020), numerous studies have been conducted over the past decades, such as the TC's asymmetrical structure of winds, rainfalls, and clouds (Liang & Chan, 2021; Tsukada & Horinouchi, 2020; Yan et al., 2020; G. Zhang et al., 2020; G. Zhang & Perrie, 2018). However, little research pertaining to the water vapor during the TC events has been carried out.…”