 Announcing the Final Examination of Mr. Liang Hong for the degree of Doctor of Philosophy in Electrical Engineering Date: Oct. 9, 2007 Outline of Studies: The removal of systematic brightness temperature biases (Tb) is necessary when producing decadal passive microwave data sets for weather and climate research. To achieve this goal, techniques were investigated to reach Tb measurement agreement among a constellation of satellites as well as to maintain sustained calibration accuracy over the lifetime of each satellite sensor. In-orbit techniques provide such a long term, group-wise solution. Calibrations were performed between sun-synchronous polar orbiting satellites (such as, WindSat and AMSR) using the non-sun synchronous radiometer TMI as a proxy. Near-simultaneous pair-wise comparisons of measurements over tropical oceans were applied in the calibration of each pair, TMI with WindSat or AMSR. Since radiometers operate at different frequencies and viewing angles, Tb normalizations were made before making intermediate comparisons. These normalizations were built on Taylor series expansion of Tb functions of the above two interested parameters. The analysis of variation of Tb’s with frequencies was based on simulations using an oceanic Radiative Transfer Model (RTM) over a wide variety of environmental conditions. The RTM model was refined and tested by comparison with collocated WindSat measurements to achieve the accuracy in simulating Tb retrievals for building transfer functions. Calibration results on months of collocated data that cover a wide span of time period and all over the longitudes were discussed along with prediction accuracy and error source analysis. This inter-satellite radiometric calibration developed a technical support for NASA’s Global Precipitation Mission which relies on a constellation of cooperative satellites with a variety of microwave radiometers to make global rainfall measurements. Educational Career: Committee in Charge: Approved for distribution by W. L. Jones, Committee Chair, on September 16, 2007. The public is welcome to attend.
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