Hyper-Angular Rainbow Polarimeter 2

HARP2 is a wide-angle hyper-angular imaging polarimeter carried on PACE for aerosol, cloud, land, and water-surface polarimetric observations.^[1] It measures four VNIR bands centred at 441, 549, 669, and 873 nm, with 10 nm bandwidths for the blue, green, and red bands and a 40 nm bandwidth for the near-infrared band.^[1] Each band measures three angles of linear polarization, and the instrument provides up to 60 along-track views, with 60 views at 669 nm and 10 views in the other three bands.^[1] The field of view is 94 degrees cross-track and +/-57 degrees along-track.^[1] Coverage is two days globally at 2.6 km resolution; the nadir-swath value is 1556 km, while a 2400 km swath figure is also published for HARP2.^[1][2] HARP2 performs multi-angle polarimetry demonstrated on PACE, supporting aerosol microphysical retrieval, cloud particle-property retrieval, and polarimetric surface observations.^[1]