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Impact of Airborne Dust on Sea Surface Temperature Retrievals

Title: Impact of Airborne Dust on Sea Surface Temperature Retrievals.
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Name(s): Bogdanoff, Alec Setnor, author
Clayson, Carol Anne, professor directing thesis
Bourassa, Mark A., committee member
Liu, Guosheng, committee member
Westphal, Douglas L., committee member
Department of Earth, Ocean and Atmospheric Sciences, degree granting department
Florida State University, degree granting institution
Type of Resource: text
Genre: Text
Issuance: monographic
Date Issued: 2010
Publisher: Florida State University
Place of Publication: Tallahassee, Florida
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: Sea Surface Temperatures (SSTs) are an important measure of our current weather and climate, as well as an essential variable in both short and long term weather forecasting. Infrared SST retrievals are reliant on passive sensors, and retrieval techniques are influenced by changes in atmospheric composition, including aerosols. Many empirically derived retrieval algorithms are based on matching Top of Atmosphere (TOA) Brightness Temperatures (BTs) from the Advanced Very High Resolution Radiometer (AVHRR) to buoy measurements during clear-sky conditions. Data is cloud-cleared to remove cloud-contaminated data. However, small, but influential, Aerosol Optical Depths (AODs) data may not be flagged as contaminated and the algorithms incorrectly calculate a cold SST due to the radiometer sensing the cooler, elevated aerosol layer temperature. Many studies on aerosol effects on SSTs focus on aerosols due to volcanic eruptions. However, truly operational tropospheric aerosol corrections for daytime and nighttime retrievals have yet to be implemented. This work constitutes a first step to creating an accurate aerosol correction by exploring the sensitivity of aerosols on SSTs. The Santa Barbra DISORT Radiative Transfer model is used to quantify the effects of aerosol contamination on retrieved TOA BTs. The calculated radiances are spectrally averaged over each channel, converted to BTs, and used to calculate an SST using the Naval Oceanographic Office AVHRR algorithms. A radiative transfer model is used to evaluate the SST retrieval error due to varying AOD, height of an aerosol layer, and the satellite zenith angle (or viewing angle). This analysis shows that errors greater than the stated retrieval uncertainty of 0.5 K are observed for AODs greater than 0.25. Two sites with state-of-the-art aerosol measurements are analyzed for AOD variability. The first site, at Anmyon in east Asia, is found to have 14% of the days during the springtime with an AOD greater than 0.25. Based on the AERONET data from a second site in Cape Verde, 65% of the days during the boreal summer are found to have AOD greater than 0.25. Unfortunately, this seasonal peak in dust activity coincides with the active tropical cylogensis season for the region, making accurate SSTs even more vital for prediction purposes.
Identifier: FSU_migr_etd-3629 (IID)
Submitted Note: A Thesis submitted to the Department of Earth, Ocean and Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science.
Degree Awarded: Fall Semester, 2010.
Date of Defense: October 19, 2010.
Keywords: Dust, Retrieval Error, Aerosols, Sea Surface Temperature
Bibliography Note: Includes bibliographical references.
Advisory Committee: Carol Anne Clayson, Professor Directing Thesis; Mark A. Bourassa, Committee Member; Guosheng Liu, Committee Member; Douglas L. Westphal, Committee Member.
Subject(s): Oceanography
Atmospheric sciences
Meteorology
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_migr_etd-3629
Owner Institution: FSU

Choose the citation style.
Bogdanoff, A. S. (2010). Impact of Airborne Dust on Sea Surface Temperature Retrievals. Retrieved from http://purl.flvc.org/fsu/fd/FSU_migr_etd-3629