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Wave and Wind Direction Effects on Ocean Surface Emissivity Measurements in High Wind Conditions

Title: Wave and Wind Direction Effects on Ocean Surface Emissivity Measurements in High Wind Conditions.
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Name(s): Holbach, Heather Marie, author
Bourassa, Mark Allan, 1962-, professor directing dissertation
McGee, Daniel, university representative
Hart, Robert E. (Robert Edward), 1972-, committee member
Liu, Guosheng, (Professor of Earth, Ocean and Atmospheric Science), committee member
Clarke, Allan J., committee member
Uhlhorn, Eric, committee member
Powell, Mark Dillon, committee member
Florida State University, degree granting institution
College of Arts and Sciences, degree granting college
Department of Earth, Ocean, and Atmospheric Science, degree granting department
Type of Resource: text
Genre: text
Issuance: monographic
Date Issued: 2016
Publisher: Florida State University
Place of Publication: Tallahassee, Florida
Physical Form: computer
Physical Form: online resource
Extent: 1 online resource (85 pages)
Language(s): English
Abstract/Description: Wave and wind direction effects on remote sensing measurements of ocean surface emissivity are investigated using a microwave radiometer in high wind conditions with a focus on tropical cyclones. Surface wind speed, which drives many atmospheric and oceanic phenomena, can be inferred from the ocean surface emissivity measurements through the use of a radiative transfer model and inversion algorithm. The accuracy of the ocean surface emissivity to wind speed calibration relies on accurate knowledge of the surface variables that are influencing the ocean surface emissivity. This study will identify an asymmetry in ocean surface emissivity measurements at off-nadir incidence angles that is related to the surface wind direction modifying the distribution of whitewater coverage, which is composed of active whitecaps and residual foam that persists after wave breaking, on the ocean surface in high wind conditions viewed by the radiometer. It will also be shown that asymmetries are present in ocean surface emissivity measurements from a nadir pointing instrument in hurricanes. This asymmetry can be related to swell and wind wave propagation directions with respect to the wind direction modifying the stress on the ocean surface, which presumably impacts the wave breaking and thus the whitewater coverage characteristics on the ocean surface. These results help achieve the study goals: 1) improving the understanding of how wave and wind direction modify ocean surface emissivity in high wind conditions and 2) identifying conditions, particularly in tropical cyclones, where wind direction and sea state modify the ocean surface emissivity and should be considered in order to further improve algorithms for the remote sensing of the surface wind.
Identifier: FSU_FA2016_Holbach_fsu_0071E_13475 (IID)
Submitted Note: A Dissertation submitted to the Department of Earth, Ocean and Atmospheric Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
Degree Awarded: Summer Semester 2016.
Date of Defense: August 2, 2016.
Keywords: Brightness Temperature, Emissivity, High Wind, Microwave Radiometer, Remote Sensing, Tropical Cyclones
Bibliography Note: Includes bibliographical references.
Advisory Committee: Mark A. Bourassa, Professor Directing Dissertation; Dan McGee, University Representative; Robert Hart, Committee Member; Guosheng Liu, Committee Member; Allan Clarke, Committee Member; Eric Uhlhorn, Committee Member; Mark Powell, Committee Member.
Subject(s): Meteorology
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_FA2016_Holbach_fsu_0071E_13475
Owner Institution: FSU