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 (CD), the effect of spray on TC evolution should depends on CDparameterization, while this has not been addressed so far. This study examines the effects of sea spray on the simulated TC evolution with two different CDparameterizations (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 CDscheme is used, but becomes weaker when the Donelan CDscheme is used. This occurs because CDis 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 CDscheme is used. In addition, the spray effect on the TC inner‐core size evolution also weakly depends on the drag parameterization. When CDis relatively greater outside the RMW, the inclusion of the spray effect would lead to the inner‐core size increase.
Characteristics of tropical cyclones (TCs) in global climate models (GCMs) are known to be influenced by details of the model configurations, including horizontal resolution and parameterization schemes. Understanding model-to-model differences in TC characteristics is a prerequisite for reducing uncertainty in future TC activity projections by GCMs. This study performs a process-level examination of TC structures in eight GCM simulations that span a range of horizontal resolutions from 1° to 0.25°. A recently developed set of process-oriented diagnostics is used to examine the azimuthally averaged wind and thermodynamic structures of the GCM-simulated TCs. Results indicate that the inner-core wind structures of simulated TCs are more strongly constrained by the horizontal resolutions of the models than are the thermodynamic structures of those TCs. As expected, the structures of TC circulations become more realistic with smaller horizontal grid spacing, such that the radii of maximum wind (RMW) become smaller, and the maximum vertical velocities occur off the center. However, the RMWs are still too large, especially at higher intensities, and there are rising motions occurring at the storm centers, inconsistently with observations. The distributions of precipitation, moisture, and radiative and surface turbulent heat fluxes around TCs are diverse, even across models with similar horizontal resolutions. At the same horizontal resolution, models that produce greater rainfall in the inner-core regions tend to simulate stronger TCs. When TCs are weak, the radial gradient of net column radiative flux convergence is comparable to that of surface turbulent heat fluxes, emphasizing the importance of cloud–radiative feedbacks during the early developmental phases of TCs.
more » « less- NSF-PAR ID:
- 10131574
- Publisher / Repository:
- American Meteorological Society
- Date Published:
- Journal Name:
- Journal of Climate
- Volume:
- 33
- Issue:
- 4
- ISSN:
- 0894-8755
- Page Range / eLocation ID:
- p. 1575-1595
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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