SPEXone Polarimeter

SPEXone is a compact passive optical multi-angle channeled spectropolarimeter on PACE for aerosol and cloud polarimetric retrievals. ^{[1] [2]} It measures radiance and linear polarization continuously from 385 to 770 nm. ^{[1] [3]} Radiance spectral resolution is 2-5 nm, and degree-of-linear-polarization resolution is 10-40 nm. ^[1] The instrument provides about 5.4 x 4.6 km spatial resolution, about 2.7 x 2.3 km spatial sampling, and an approximately 100 km swath. ^{[1] [3]} SPEXone acquires five ground viewing angles for multi-angle polarimetry, including nadir and +/-58 degree views. ^{[1] [3]} Specified accuracy is 0.003 polarimetric and 2 percent radiometric. ^[1] Multi-angle polarimetry is demonstrated on PACE through SPEXone's mission role, with a narrow swath that complements broader ocean-colour and atmospheric sensors on the same platform. ^[1]