Land Polarized Reflectance Analysis Using Space Lidar
Abstract
We study the Earth surface polarized reflectance using data from the Cloud-Aerosol Transport System (CATS: M. McGill, J. Yorks, E. Nowottnick, et al.: https://cats.gsfc.nasa.gov/). CATS is a lidar operated on board the International Space Station from 02/2015 to 10/2018. CATS measured cross polarization components at 532nm and 1064nm, in left and right fields of view (L&R FOV), 7km apart the footprints (02/15-03/21 2015). Using this data, it is possible to check if the surface polarized reflectance obeys the Fresnel law and spectrally neutral. Strong polarization of the laser light and high signal-to-noise ratio during nighttime measurements compensate the obvious disadvantage of the single view geometry (backscattering).
Our preliminary analysis of ~2500 clear pixels along the US West coast (02/16) and ~6500 pixels in Africa (02/23) indicates that: a) contrary to the Fresnel model, a strong perpendicular component reflects from the ground; b) ratio of the perpendicular to parallel component is different in the 2 bands. The ratio removes the atmospheric attenuation factor and minimizes the effect of multiplicative calibration error, while CATS significantly reduces the additive noise by averaging ~230 measurements within the ~350m (L1B along-the-track spatial resolution). Contrary to our expectation, we observe noticeable average difference between the L&R FOV at 1064nm. Accurate modeling of the surface polarized reflectance supports retrieval algorithm development for processing the existing (e.g., POLDER) and future (e.g., PACE, 3MI) Earth remote sensing data.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A13A..05K
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0319 Cloud optics;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0360 Radiation: transmission and scattering;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 4275 Remote sensing and electromagnetic processes;
- OCEANOGRAPHY: GENERAL