This proposal from the university of central florida, central florida remote sensing laboratory (cfrsl), in collaboration with data and image processing consultants (dipcon), is to conduct…

This federal contract award is a research grant from the National Aeronautics and Space Administration (NASA) to the University of Central Florida's Central Florida Remote Sensing Laboratory (CFRSL), in collaboration with Data and Image Processing Consultants (DIPCON). The $395,860 grant supports analytical work to refine methodologies for the intercalibration of brightness temperature radiance measurements from passive microwave radiometer sensors across the satellites of the Global Precipitation Measurement (GPM) mission constellation. The objective is to improve the consistency of rainfall retrievals between the different instruments to enhance the quality of the GPM merged precipitation product. This effort builds upon the awardee's prior experience with the GPM Intercalibration (XCAL) Working Group. The research will provide critical radiometric bias tables to support maintenance of the GPM sensor algorithms used in the Precipitation Processing System. This grant is not associated with any set-aside program.

This proposal from the university of central florida, central florida remote sensing laboratory (cfrsl), in collaboration with data and image processing consultants (dipcon), is to conduct analytical cross calibration techniques for cooperative satellites within the multi satellite global precipitation mission (GPM) constellation. The objective is the refinement of methodologies for the inter calibration of brightness temperature radiance measurements from passive microwave radiometer sensors, which supports the PMM science team NRA call for scientific investigations related to development, evaluation, and validation of trmm and GPM retrieval algorithms: 2.1 algorithm product validation and enhancement development of methodologies for the intercalibration of measurements from microwave sensors. Our research objective is simple, GPM will reduce errors in global rainfall estimates associated with temporal spatial sampling by using a constellation of satellites. In order for the merged product to be satisfactory, the rainfall retrievals from each instrument must be consistent with the others, and this begins with the basic sensor radiance measurements (brightness temperature, TB)fundamental to this concept is the existence of the GPM observatory (with GMI) in non sun synchronous orbit, which serves as a radiometric transfer standard for the other passive microwave sensors on cooperative constellation satellites. This proposal builds upon our previous PMM science team experience with the inter satellite calibration working group (x CAL). We will continue to provide an on orbit assessment of systematic calibration errors (to an accuracy of order 0.1 k) as a function of instrument and satellite parameters e.g. critical instrument temperatures, solar beta angle, and spacecraft attitude. The calibration error sources and their root causes will be identified, and appropriate radiometric calibration correction algorithms will be developed. This activity provides critical radiometric bias tables for the constellation radiometers in support the GPM sensor algorithms maintenance for the precipitation processing system. The primary objective of this proposal is to extend previous x CAL results by conducting comprehensive pair wise inter satellite radiometric comparisons between the GPM microwave imager (GMI) and constellation member radiometers (both imagers and sounders). A significant part of this research is the xcal between the previous radiometric standard (trmm microwave imager, TMI) and the new standard, GMI. Since the launch of GPM (FEB 2014) and the on orbit checkout of the GMI (60 days thereafter),cfrsl has been an active participant in this activity, and we now have preliminary analysis of one year of inter comparison with TMI. However, evaluation of GMI is an on going process to assess its on orbit radiometric stability continuously with other satellite radiometers. While the trmm mission has now ended, we are fortunate to have the windsat, with which cfrsl has established over one decade of xcal with TMI. Results have shown the relative calibration stability between these two sensors has been of order 0.1 k for over one decade. This implies that both sensors are radiometrically stable within this uncertainty bound. Therefore, we propose to continue windsat GMI xcal to link the future radiometric calibration of the GMI constellation to the past 18 years of the trmm precipitation data products. Moreover, we plan to incorporate lessons learned from recent TMI deep space calibration maneuvers (may 2015) to refine the TMI brightness temperature product 1B11 version 8 for the trmm archival dataset.