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DEVELOPMENT OF AN IMPROVED MICROWAVE OCEAN SURFACE EMISSIVITY RADIATIVE TRANSFER MODEL
Title
DEVELOPMENT OF AN IMPROVED MICROWAVE OCEAN SURFACE EMISSIVITY RADIATIVE TRANSFER MODEL.
Creator
El-Nimri, Salem, Jones, W. Linwood, University of Central Florida
Abstract / Description
An electromagnetic model is developed for predicting the microwave blackbody emission from the ocean surface over a wide range of frequencies, incidence angles, and wind vector (speed and direction) for both horizontal and vertical polarizations. This ocean surface emissivity model is intended to be incorporated into an oceanic radiative transfer model to be used for microwave radiometric applications including geophysical retrievals over oceans. The model development is based on a collection...
Show moreAn electromagnetic model is developed for predicting the microwave blackbody emission from the ocean surface over a wide range of frequencies, incidence angles, and wind vector (speed and direction) for both horizontal and vertical polarizations. This ocean surface emissivity model is intended to be incorporated into an oceanic radiative transfer model to be used for microwave radiometric applications including geophysical retrievals over oceans. The model development is based on a collection of published ocean emissivity measurements obtained from satellites, aircraft, field experiments, and laboratory measurements. This dissertation presents the details of methods used in the ocean surface emissivity model development and comparisons with current emissivity models and aircraft radiometric measurements in hurricanes. Especially, this empirically derived ocean emissivity model relates changes in vertical and horizontal polarized ocean microwave brightness temperature measurements over a wide range of observation frequencies and incidence angles to physical roughness changes in the ocean surface, which are the result of the air/sea interaction with surface winds. Of primary importance are the Stepped Frequency Microwave Radiometer (SFMR) brightness temperature measurements from hurricane flights and independent measurements of surface wind speed that are used to define empirical relationships between C-band (4 – 7 GHz) microwave brightness temperature and surface wind speed. By employing statistical regression techniques, we develop a physical-based ocean emissivity model with empirical coefficients that depends on geophysical parameters, such as wind speed, wind direction, sea surface temperature, and observational parameters, such as electromagnetic frequency, electromagnetic polarization, and incidence angle.
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Date Issued
2010
Identifier
CFE0003085, ucf:48323
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0003085
VALIDATION OF WIDEBAND OCEAN EMISSIVITY RADIATIVE TRANSFER MODEL
Title
VALIDATION OF WIDEBAND OCEAN EMISSIVITY RADIATIVE TRANSFER MODEL.
Creator
Crofton, Sonya, Jones, Linwood, University of Central Florida
Abstract / Description
Radiative Transfer Models (RTM) have many applications in the satellite microwave remote sensing field, such as the retrieval of oceanic and atmospheric environmental parameters, including surface wind vectors and sea surface temperatures, integrated water vapor, cloud liquid, and precipitation. A key component of the ocean RTM is the emissivity model used to determine the brightness temperature (Tb) at the oceanÂÂ's surface. A new wideband ocean emissivity RTM...
Show moreRadiative Transfer Models (RTM) have many applications in the satellite microwave remote sensing field, such as the retrieval of oceanic and atmospheric environmental parameters, including surface wind vectors and sea surface temperatures, integrated water vapor, cloud liquid, and precipitation. A key component of the ocean RTM is the emissivity model used to determine the brightness temperature (Tb) at the oceanÂÂ's surface. A new wideband ocean emissivity RTM developed by the Central Florida Remote Sensing Laboratory (CFRSL) calculates ocean emissivity over a wide range of frequencies, incidence angles, sea surface temperatures (SST), and wind speed. This thesis presents the validation of this CFRSL model using independent WindSat Tb measurements collocated with Global Data Assimilation System (GDAS) Numerical weather model environmental parameters for frequencies between 6.8 to 37 GHz and wind speeds between 0 – 20 m/s over the July 2005 – June 2006 year. In addition, the CFRSL emissivity model is validated using WindSat derived ocean wind speeds and SST that are contained in the Environmental Data Record (EDR) and combined with the GDAS environmental parameters. Finally, the validation includes comparisons to the well-established XCAL ocean emissivity RTM. The focus of this validation and comparison is to assess performance of the emissivity model results with respect to a wide range of frequency and wind speeds but limited to a narrow range of incidence angles between approximately 50° - 55°.
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Date Issued
2010
Identifier
CFE0003533, ucf:48946
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0003533