ORCID Profile
0000-0001-6033-1651
Current Organisations
University of Hawai'i
,
Tsinghua University
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Publisher: American Geophysical Union (AGU)
Date: 16-08-2022
DOI: 10.1029/2022JD037039
Abstract: This study examines the possible dependence of tropical cyclone (TC) development on the initial winds inside the radius of maximum wind (RMW) through ensemble axisymmetric numerical simulations. Results demonstrate that the vortex with higher initial winds inside the RMW favor larger surface enthalpy flux and thus faster moistening and earlier convective organization in the inner core, significantly shortening the initial spinup period. Higher inertial stability associated with higher winds inside the RMW implies higher eyewall‐heating efficiency, giving rise to higher intensification rate in the subsequent intensification stage but little difference in the steady‐state intensity. The results are confirmed with several sensitivity experiments using different model parameters and three‐dimensional simulations using the same model and configuration. The findings from this study strongly suggest that the realistic representation of the initial inner‐core winds is key to skillful TC intensity forecasts by numerical models and routine high‐resolution observations of the inner‐core wind structure are urged for improving TC intensity forecasts.
Publisher: American Geophysical Union (AGU)
Date: 10-01-2023
DOI: 10.1029/2022JD037299
Abstract: Wave breaking under strong wind conditions in tropical cyclones (TCs) can generate sea spray droplets, which, during their suspension in air, release sensible heat due to the air‐sea temperature difference while absorb sensible heat from the environment when they evaporate and release latent heat to the environment. Since the spray mass flux is a function of surface drag coefficient (C D ), the effect of spray on TC evolution should depends on C D parameterization, while this has not been addressed so far. This study examines the effects of sea spray on the simulated TC evolution with two different C D parameterizations (the Weather Research and Forecasting (WRF) default scheme and the Donelan scheme). Results show that during the primary intensification stage, the TC with spray effect becomes stronger than that without spray when the WRF C D scheme is used, but becomes weaker when the Donelan C D scheme is used. This occurs because C D is maximum outside the radius of maximum wind (RMW) with the Donelan scheme, which produces relatively large spray‐mediated latent heat flux outside the RMW, which is unfavorable for TC intensification. The difference is enlarged by a feedback between spray and TC intensification involving the inertial stability and surface friction‐induced radial inflow. However, in the mature stage, the simulated TCs with spray become stronger no matter which C D scheme is used. In addition, the spray effect on the TC inner‐core size evolution also weakly depends on the drag parameterization. When C D is relatively greater outside the RMW, the inclusion of the spray effect would lead to the inner‐core size increase.
Publisher: American Geophysical Union (AGU)
Date: 15-10-2019
DOI: 10.1029/2019JD030600
Publisher: American Geophysical Union (AGU)
Date: 15-11-2022
DOI: 10.1029/2022GL101027
Abstract: The statistical relationship between the ending times of hurricane intensification and contraction of the radius of maximum wind (RMW) over the North Atlantic (NA) and Eastern North Pacific (EP) is assessed using the Extended Best Track and Tropical Cyclone Observations‐Based Structure databases during 1999–2014. Results show that in more than half of hurricanes the end of RMW contraction precedes the end of intensification, and those hurricanes generally have lower relative intensity (intensity normalized by the corresponding maximum potential intensity) and larger curvature of the tangential wind profile at the RMW. The preceding time tends to be longer with lower relative intensity and lower intensification rate and on average is longer in the NA (∼19 hr) than in the EP (∼12 hr) due to the overall lower intensification rate in the former. These findings can help improve our understanding of hurricane structure and intensity changes.
No related grants have been discovered for Yuanlong Li.