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theses

This dissertation uses the integration of modeling with observations and new analysis techniques to better understand and predict how the stratified coastal ocean interacts with important summer weather processes—tropical cyclones (TCs), which incur large coastal and inland damages, and the sea breeze circulation, which occurs nearly daily in the summer during high electricity demand periods. TC intensity prediction skill lags TC track prediction skill, and the shallow, coastal ocean remains a gap in TC research. The offshore component of the sea breeze is under-observed and poorly understood relative to its onshore component, and has important wind resource implications for the burgeoning U.S. offshore wind energy industry. Using atmospheric modeling and coastal ocean observations with underwater gliders and buoys, it is shown in Hurricane Irene (2011) that stratified coastal ocean cooling—found to occur primarily ahead of the storm’s eye center offshore the U.S. MidAtlantic—was the key missing contribution in modeling Irene’s rapid decay just prior to NJ landfall. Irene’s intensity was more sensitive to this cooling than any other model parameter tested, and including this cooling in modeling mitigated the high bias in storm intensity predictions. Using ocean modeling, the spatiotemporal variability in the stratified coastal ocean cooling processes observed in Irene and Tropical Storm Barry (2007) was investigated. It was found that the dominant force balance across the entire Mid-Atlantic shelf ahead of storm eye passage for both storms was onshore wind stress balanced by offshore pressure gradient. This resulted in onshore surface currents opposing offshore bottom currents ahead-of-eye-center and enhancing surface to bottom current shear and surface cooling. Turbulent mixing cooled the surface layer while tides dominated the alternating warming/cooling advection signal. Finally, a new analysis technique, i.e. Lagrangian coherent structures, performed on atmospheric modeling was used to delineate the onshore surface convergent and offshore surface divergent sea breeze extents. It was found that atmospheric synoptic flow impacted the sea breeze onshore extent more than offshore extent, and that coastal upwelling did not impact sea breeze extent but rather caused an earlier onset and a shallower and more intense sea breeze both onshore and offshore.

ETD_7552

Ph.D.

Includes bibliographical references

by Greg Seroka

doi:10.7282/T3KP84G7

ETD doctoral

The author owns the copyright to this work.