The Polarimetric Scanning Radiometer (PSR) is a versatile aircraft-mounted microwave imaging radiometer developed for obtaining polarimetric microwave emission imagery of Earth's oceans, land, ice, clouds, and precipitation. Polarimetric data are helpful for resolving the finer details of imagery and determining the orientation of smaller structures. The device is mounted on gimbals, allowing it to be rotated to view any angle within about 70° elevation of nadir at any azimuthal angle (a total of 1.32 sr solid angle), as well as external hot and ambient calibration targets. The configuration thus supports conical, cross-track, along-track, fixed-angle stare, and spotlight scan modes.
PSR is the first airborne scanned polarimetric imaging radiometer suitable for post-launch satellite calibration and validation of a variety of spaceborne passive microwave sensors. PSR can be installed on NASA aircraft including the DC-8, P3-Orian, and WB-57.
PSR supports several observational objectives:
- to provide polarimetric imagery of the upwelling thermal emission field at several of the most important microwave remote sensing bands covering X to W band in octave intervals and including the 22.235 GHz water vapor line. The current implementation provides full Stokes vector (four parameters Tv, Th, TU, and TV) capability at 10.7 and 18.7 GHz, tripolarimetric capability (Tv, Th, and TU) at 37.0 and 89.0 GHz, and dual polarization capability (Tv and Th) at 21.5 GHz
- to provide the above measurements with absolute accuracy of better than 1 K for Tv and Th, and 0.1 K for TU and TV
- to provide radiometric imaging with both fore and aft look capability (rather than single swath observations)
- to provide conical imagery at a variety of surface incidence angles
- to provide image resolutions appropriate for spatially- resolved studies of precipitating and non-precipitating clouds, mesoscale ocean surface features, and satellite calibration/validation at Nyquist spatial sampling rates
PSR has been integrated into the nadir-7 port of the DC-8 for CAMEX-3 and will be primarily operated in a 52o conically-scanned mode. A unique new moving-map radiometric display for PSR will be used to provide near real-time brightness temperature imagery for both scientific and flight operations purposes. The display will provide conically-scanned brightness temperature maps at the five PSR bands and for several polarizations.