Numerical Simulations of a Florida Sea Breeze and Its Interactions with Associated Convection: Effects of Geophysical Representation and Model Resolution

The Florida peninsula in the USA has a frequent occurrence of sea breeze (SB) thunderstorms. In this study, the numerical simulation of a Florida SB and its associated convective initiation (CI) is simulated using the mesoscale community Weather Research and Forecasting (WRF) model in one-way nested domains at different horizontal resolutions. Results are compared with observations to examine the accuracy of model-simulated SB convection and factors that influence SB CI within the simulation. It is found that the WRF model can realistically reproduce the observed SB CI. Differences are found in the timing, location, and intensity of the convective cells at different domains with various spatial resolutions. With increasing spatial resolution, the simulation improvements are manifested mainly in the timing of CI and the orientation of the convection after the sea breeze front (SBF) merger into the squall line over the peninsula. Diagnoses indicate that accurate representation of geophysical variables (e.g., coastline and bay shape, small lakes measuring 10-30 km(2)), better resolved by the high resolution, play a significant role in improving the simulations. The geophysical variables, together with the high resolution, impact the location and timing of SB CI due to changes in low-level atmospheric convergence and surface sensible heating. More importantly, they enable Florida lakes (30 km2 and larger) to produce noticeable lake breezes (LBs) that collide with the SBFs to produce CI. Furthermore, they also help the model reproduce a stronger convective squall line caused by merging SBs, leading to more accurate locations of postfrontal convective systems.

Automated summary

In this study, the numerical simulation of sea breeze (SB) and its associated convective initiation (CI) in the Florida peninsula was conducted using the WRF model. The results show that the WRF model can accurately reproduce the observed SB CI, and the resolution and accurate representation of geophysical variables play a significant role in improving the simulations.