Date of Award

2013

Degree Type

Thesis

Degree Name

Master of Science in Oceanography

Department

Oceanography

First Advisor

Isaac Ginis

Abstract

Although hurricane models can now more accurately forecast storm track, they have not made significant improvement in forecasting hurricane intensity. Sea surface temperature and ocean heat content play an important role in regulating tropical cyclone intensity. The focus of this chapter is on ocean model resolution. The Princeton Ocean Model (POM) is used to calculate the temperature fields under a specified hurricane wind stress, utilizing an idealized storm structure.

This study examines ocean model response under idealized hurricane conditions for a range of horizontal resolutions spanning from ½° to 1/18°. Resolution sensitivity was examined for different storm speeds, different storm sizes, different model physics (3D or 1D) and different initial ocean conditions. The higher resolution experiments better represent the structure of the hurricane eye and the eyewall. It is found that the magnitude of sea surface temperature (SST) in the cold wake is less at coarser resolutions than at finer resolutions. Horizontal resolution is more important in experiments with 3D physics than 1D physics. Horizontal resolution has a larger impact in resolving slower moving storms than faster moving storms. Latent heat flux is also generally larger at higher resolutions than coarser resolutions. The values of SST, latent heat flux, and turbulent kinetic energy (TKE) converge in experiments with 1/12° and 1/18° grid spacing. Ocean heat uptake (OHU) increases as resolution increases. Vertical resolution also plays an important role in ocean heat loss and uptake estimations. Vertical grid spacing of at least 5 m in the mixed layer and at least 10 m in the upper thermocline are necessary for accurate calculations of ocean heat loss and uptake.

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