Study of the Boundary Layer Structure of a Landfalling Typhoon Based on the Observation from Multiple Ground-Based Doppler Wind Lidars

Wenhao Shi; Jie Tang; Yonghang Chen; Nuo Chen; Qiong Liu; Tongqiang Liu

doi:10.3390/rs13234810

Remote Sensing (Nov 2021)

Study of the Boundary Layer Structure of a Landfalling Typhoon Based on the Observation from Multiple Ground-Based Doppler Wind Lidars

Wenhao Shi,
Jie Tang,
Yonghang Chen,
Nuo Chen,
Qiong Liu,
Tongqiang Liu

Affiliations

Wenhao Shi: College of Environmental Science and Engineering, Donghua University, Shanghai 201600, China
Jie Tang: Shanghai Typhoon Institute, China Meteorological Administration, Shanghai 200030, China
Yonghang Chen: College of Environmental Science and Engineering, Donghua University, Shanghai 201600, China
Nuo Chen: Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, 1225 W. Dayton Street, Madison, WI 53706, USA
Qiong Liu: College of Environmental Science and Engineering, Donghua University, Shanghai 201600, China
Tongqiang Liu: College of Environmental Science and Engineering, Donghua University, Shanghai 201600, China

DOI: https://doi.org/10.3390/rs13234810
Journal volume & issue: Vol. 13, no. 23
p. 4810

Abstract

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The boundary layer structure is crucial to the formation and intensification of typhoons, but there is still a lack of high-precision turbulence observations in the typhoon boundary layer due to limitations of the observing instruments under typhoon conditions. Using joint observations from multiple ground-based Doppler wind lidars (DWL) collected by the Shanghai Typhoon Institute of China Meteorological Administration (CMA) during the transit of Typhoon Lekima (8–11 August 2019), the characteristics of the wind field and physical quantities (including turbulent kinetic energy (TKE) and typhoon boundary layer height (TBLH)) of the boundary layer of typhoon Lekima were analyzed. The magnitude of TKE was shown to be related not only to the horizontal wind speed but also to the presence of a strong downdraft, which leads to a rapid increase of TKE. The magnitudes of TKE in different quadrants of Typhoon Lekima were also found to differ. The TKE in the front right quadrant of the typhoon was 2.5–6.0 times that in the rear left quadrant and ~1.7 times that in the rear right quadrant. The TKE over the island was larger than that over the urban area. Before Typhoon Lekima made landfall, the TKE increased with decreasing distance to the typhoon center. After typhoon landfall, the TKE changes were different on the left and right sides of the typhoon center, with the TKE on the left decreasing rapidly, while that on the right changed little. The typhoon boundary layer height calculated by five methods was compared and was found to decrease gradually before typhoon landfall and increased gradually afterward. The trends of the TBLH calculated using helicity and TKE were consistent, and both determine the TBLH well, while the maximum tangential wind speed height (humax) was larger than the height calculated by other methods. This study confirms that DWL has a strong detecting capability for the finescale structure of the typhoon boundary layer and provides a powerful tool for the validation of numerical simulations of typhoon structure.

Published in Remote Sensing

ISSN: 2072-4292 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Science
Website: http://www.mdpi.com/journal/remotesensing/

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