A Simulation of Hurricane Landfall with a Numerical Model Featuring Latent Heating by the Resolvable Scales

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  • 1 NOAA/Atlantic Oceanographic and Meteorological Laboratory, Hurricane Research Division. Miami, FL 33149
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Abstract

A nested-grid hurricane model is used to transport a strong vortex over a straight coastline at ∼4 m s&−1 The track, at landfall, of the vortex is ∼20 km to the left of a control simulation without land. Just before landfall, a 15 km amplitude trochoidal oscillation of the vortex track occurs. This amplitude is nearly double that of similar oscillations of the control simulation.

About 10 h before landfall, a spiral rainband nearly surrounds the vortex at radii of ∼135 km. This rainband has a weak secondary maximum in the tangential wind and is the model analog of the secondary eyewalls observed by Willoughby et al. in several hurricanes.

The rainfall in spiral rainbands diminishes during the 7 h before landfall. However, rainfall in the inner core of the vortex is greater during landfall than in the control simulation. The greatest rainfall accumulation is to the right of the vortex. However, compared with the control simulation, rainfall is greater to the left and less to the right of the vortex. This may be the result of an increase of the relative radial inflow in the boundary layer in the left front quadrant new landfall. To the extent which is possible, these characteristics of landfall are related to observations.

Abstract

A nested-grid hurricane model is used to transport a strong vortex over a straight coastline at ∼4 m s&−1 The track, at landfall, of the vortex is ∼20 km to the left of a control simulation without land. Just before landfall, a 15 km amplitude trochoidal oscillation of the vortex track occurs. This amplitude is nearly double that of similar oscillations of the control simulation.

About 10 h before landfall, a spiral rainband nearly surrounds the vortex at radii of ∼135 km. This rainband has a weak secondary maximum in the tangential wind and is the model analog of the secondary eyewalls observed by Willoughby et al. in several hurricanes.

The rainfall in spiral rainbands diminishes during the 7 h before landfall. However, rainfall in the inner core of the vortex is greater during landfall than in the control simulation. The greatest rainfall accumulation is to the right of the vortex. However, compared with the control simulation, rainfall is greater to the left and less to the right of the vortex. This may be the result of an increase of the relative radial inflow in the boundary layer in the left front quadrant new landfall. To the extent which is possible, these characteristics of landfall are related to observations.

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