NOAA's Earth System Research Laboratory (ESRL) has been working with the National Environmental Satellite, Data, and Information Service (NESDIS) Center for Satellite Applications and Research (StAR) and the University of Wisconsin's Cooperative Institute for Meteorological Satellite Studies (CIMSS) for about one year to improve the moisture retrieval products for operational GOES satellites[1]. The ultimate target for this work is of course the GOES-R mission, but the techniques are applicable to all infrared sounder products over land. The approach we are taking is unique in that it utilizes independent real-time observations of total precipitable water obtained from a research program (GPS Met) that is essentially “stuck” in the RTO process to facilitate the transition of a new satellite data processing algorithm into NESDIS operations. The validity of this approach is predicated on the fact that GPS water vapor observations with verifiable accuracy are available at over 300 stations over CONUS with high reliability under all weather conditions. The use of GPS observations to assess the accuracy and precision of satellite products is yet another unanticipated application of the Global Positioning System in meteorology, where the value added by GPS to other applications sometimes exceeds the intrinsic value of the refractivity observations themselves.[2] This presentation reviews the procedures used to assess the characteristics of the dominant algorithms (Ma and Li) used to estimate TPW from GOES radiance observations, and the results leading to the selection of the Li algorithm using the operational Global Forecast System for constraint as the “best technique” available at the current time. The extension of this technique to future operational monitoring of GOES radiance measurements and derived products in the absence of CLARREO data and products will be discussed.

[1] Gary S. Wade, James P. Nelson III, Amerigo S. Allegrino, Seth I. Gutman, Daniel L. Birkenheuer, Zhenglong Li, Anthony J. Schreiner, Timothy J. Schmit, Jaime Daniels, and Jun Li, 2011: Transitioning Improvements in the GOES Sounder Profile Retrieval Algorithm into Operations, 36th NWA Annual Meeting, Birmingham, AL, 15-20 Oct. 2011

[2] It should be noted that the ability to use GPS for this and other ground, air and space-based applications is currently in jeopardy because of demonstrated radio frequency interference caused by waivers granted by the Federal Communications Commission to a commercial entity: LightSquared Subsidiary LLC (http://www.pnt.gov/interference/lightsquared/)