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Abstract The hazards induced by tropical cyclones (TCs), for example, high winds, extreme precipitation, and storm tides, are closely related to the TC surface wind field. Parametric models for TC surface wind distribution have been widely used for hazards and risk analysis due to their simplicity and efficiency in application. Here we revisit the parametric modeling of TC wind fields, including the symmetrical and asymmetrical components, and its applications in storm tide modeling in the North Atlantic. The asymmetrical wind field has been related to TC motion and vertical wind shear; however, we find that a simple and empirical background‐wind model, based solely on a rotation and scaling of the TC motion vector, can largely capture the observed surface wind asymmetry. The implicit inclusion of the wind shear effect can be understood with the climatological relationship between the general TC motion and wind shear directions during hurricane seasons. For the symmetric wind field, the widely used Holland wind profile is chosen as a benchmark model, and we find that a physics‐based complete wind profile model connecting the inner core and outer region performs superiorly compared to a wind analysis data set. When used as wind forcing for storm tide simulations, the physics‐based complete wind profile integrated with the background‐wind asymmetry model can reproduce the observed storm tides with lower errors than the often‐used Holland model coupled with a translation‐speed‐based method.
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Variations in Tropical Cyclone Size and Rainfall Patterns Based on Synoptic‐Scale Moisture Environments in the North Atlantic
Abstract Prior research has shown that tropical cyclone (TC) size, which is integral in determining the spatial extent of TC impacts, is influenced by environmental wind shear and the overall moisture environment. This study considers North Atlantic TCs located within low to moderate wind shear and at least 100 km from major landmasses. An empirical orthogonal function (EOF) analysis is applied to distinguish moisture environments based on the spatial pattern of total column water vapor surrounding the TC. Using these EOF patterns, four separate categories (groups) are created. Principal component scores indicate the TC samples most contributing to each EOF pattern and ultimately determine the cases in each group. TC structural differences among the groups are compared using size metrics based on the wind and precipitation fields and shape metrics based on the precipitation field. These metrics are considered across a 48‐hr window centered on the sample times evaluated in the EOF analysis. There are no statistically significant differences in the TC wind field size, but TCs with abundant moisture to the southeast have larger rain areas with more outer rainbands. TCs in a dry environment or with dry air southeast of the TC center have generally smaller rain areas and less closed rainbands than TCs with moisture to the southeast. Future work will investigate the physical processes contributing to these spatial differences in precipitation.
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- PAR ID:
- 10614906
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Atmospheres
- Volume:
- 130
- Issue:
- 10
- ISSN:
- 2169-897X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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