Weather System Follow-on – Microwave (WSF-M) Mission On-orbit Results

The Weather System Follow-On – Microwave (WSF-M) mission represents the next generation operational capability for spaceborne monitoring of key environmental parameters including ocean surface vector winds, tropical cyclone intensity, sea ice age/concentration, snow water equivalent, and soil moisture. WSF-M builds upon the heritage of the Special Sensor Microwave/Imager (SSM/I) series of instruments, operated by the Defense Meteorological Satellite Program (DMSP), the GPM Microwave Imager (GMI) instrument, built by Ball Aerospace, and the Naval Research Laboratory’s Coriolis WindSat instrument. The WSF-M space segment consists of a high-heritage spacecraft design, a Microwave Imager (MWI) instrument, and an Energetic Charged Particles (ECP) sensor built by the Air Force Research Laboratory.

The MWI is a conically scanning, fully polarimetric microwave radiometer employing a calibration design that ensures accurate and stable on-orbit brightness temperature measurements. The WSF-M space vehicle was launched into low earth orbit on April 11, 2024. This paper provides an early look at on-orbit calibration of the MWI and validation of environmental data products to date. These include sensor radiometric calibration from calibration maneuvers using the earth and deep space as vicarious sources, a comparison of observed brightness temperature minus model background, intercomparison between on-board calibration sources and cross-calibration with other sensors. We also present early environmental data record performance relative to in-situ data and other community-recognized environmental products.