Posters

Poster Session 4, Thursday, October  6, 11:00–12:40

Poster 72

Preparing for surface refractive index retrievals for the PACE mission: simulations and prototype measurements

A novel technique, enabled by the unprecedented multiangle polarimetric capabilities of the PACE space mission, is the retrieval of the ocean surface refractive index. The technique has been previously established based on measurements by the airborne Research Scanning Polarimeter (RSP) in the sunglint region. In this work we present preparatory work to assess the expected performance of the HARP-2 sensor regarding the retrieval in question. With respect to RSP, HARP-2 leverages a smaller longest wavelength (870 nm instead of 2250 nm), and it has a lower angular resolution. It is therefore imperative to determine (i) the expected contribution of fine mode aerosols at 870 nm, which can minimally affect the Degree of Linear Polarization in the glint region exploited by the retrieval algorithm; (ii) the residual contribution of the polarized water-leaving radiances at 870 nm, since the black-pixel approximation can fail at this wavelength in the brightest waters; and (iii) the impact of the HARP-2 measurement accuracy on the retrievals. To tackle this latter objective, we have proceeded to co-locate simultaneous observations by the RSP and AirHARP sensors collected during the ACEPOL airborne mission. Both sensors are deployed on the high-altitude ER-2 aircraft, and thus the perspective is the closest to that of a satellite. A successful direct comparison of the radiometric and polarimetric signals collected at 870 nm (common to both instruments) will therefore increase the confidence that the technique can seamlessly be transitioned to spaceborne retrievals.

Matteo Ottaviani, NASA GISS / Terra Research Inc, [email protected], 0000-0002-8379-0831 

Jacek Chowdhary, Columbia University / NASA GISS, [email protected] 

Andrej Wasilewski, NASA GISS / SciSpace LLC, [email protected]