Current passive microwave sounders, such as the Advanced Microwave Sounding Unit-B (AMSU-B) and Microwave Humidity Sounder (MHS) on-board the NOAA POES satellites and EUMETSAT MetOp-A, have been designed for operational weather prediction. Their measurements are not calibrated with sufficient stability for climate applications and derived hydrological products such as precipitation and snow cover. A properly calibrated Fundamental Climate Data Record (FCDR) needs to be developed to enable the utilization of these data for Thematic CDR (TCDR) and to extend their application to the JPSS era (e.g., POES/AMSU to NPP/ATMS to JPSS/ATMS).

With the support of the NOAA CDR Project, effort is underway at NOAA/NESDIS and its Cooperative Institute for Climate and Satellites (CICS) to develop more than 10 years of FCDR from AMSU-B/MHS window channels. This includes channels 16 and 17, i.e. 89 and 150/157 GHz. Presently, six POES satellites carry AMSU-B/MHS radiometer: NOAA-15 to -19, and MetOp-A. This project aims at developing a set of consistent and inter-calibrated AMSU-B/MHS radiance CDR from this set of sensors. AMSU-B/MHS window channel measurements are potentially subject to the impact of several biases such as cross polarization, geolocation error, RFI and antenna pattern etc. These error sources contribute to either scan dependent biases or systematic biases which cause inconsistency among different satellite data. The current focus is on characterizing the scan asymmetry for each of the six AMSU-B/MHS sensors using Community Radiative Transfer Model (CRTM), ECMWF ERA-interim data, and AVHRR-based PATMOS-x data. This is initially carried out over ocean under clear sky conditions. The planned inter-satellite calibration approaches include Simultaneous Nadir Overpass (SNO), Double Difference Technique (DDT) utilizing radiative transfer model such as Community Radiative Transfer Model (CRTM), and/or vicarious calibration.

The complete project also includes the creation of FCDR from AMSU-A window channels and AMSU-B/MHS water vapor channels. These tasks are being carried out concurrently with this effort as this three-year project progresses.