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A TIME-VARYING RADIOMETRIC BIAS CORRECTION FOR THE TRMM MICROWAVE IMAGER
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TitleA TIME-VARYING RADIOMETRIC BIAS CORRECTION FOR THE TRMM MICROWAVE IMAGER
AuthorGopalan, Kaushik
KeywordsRadiometric Calibration
TMI
Inter-Satellite calibration
AbstractThis dissertation provides a robust radiometric calibration for the TRMM Microwave Imager to correct systematic brightness temperature errors, which vary dynamically with orbit position (time) and day of the year. The presence of a time-varying bias in TMI is confirmed by inter-calibration with WindSat and SSMI. This time varying bias is manifested as a time of day dependent variation of the relative biases between TMI and both WindSat and SSMI. In this dissertation, we provide convincing evidence that this time-varying Tb bias in TMI is caused by variations in the physical temperature of the emissive TMI reflector antenna. This dissertation provides an empirical correction that largely corrects this time-varying bias. The TMI bias is estimated by comparing the 10.7 GHz V-polarization channel observations with RTM Tb predictions, and the Tb correction is applied as a function of orbit time for every day of the one year period. Furthermore, this dissertation provides a qualitative physical basis for the estimated Tb bias patterns and provides conclusive evidence that the empirical correction applied to TMI Tb measurements (both ocean and land) largely corrects the time-varying TMI calibration. This is accomplished by demonstrating that the local time-of-day dependence (in the uncorrected TMI Tb values) is removed in the corrected TMI Tb's.
AdviserJones, W. Linwood
PublisherUniversity of Central Florida
DegreePh.D.
Degree DisciplineSchool of Electrical Engineering and Computer Science
Degree GrantorEngineering and Computer Science
Degree ProgramElectrical Engineering PhD
Graduation Date2008-01-01
TypeDoctoral dissertation
Access LevelPublic - Allow Worldwide Access
Release Date2008-12-20
RepositoryUniversity Archives
Repository CollectionElectronic Theses and Dissertations
IdentifierCFE0002495
Access Linkhttp://purl.fcla.edu/fcla/etd/CFE0002495

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