New ocean subsurface optical properties from space lidars:
CALIOP/CALIPSO and ATLAS/ICESat-2
Abstract
Remote sensing from Earth-observing satellites is now providing valuable
information about the ocean phytoplankton distributions. This paper
presents the new ocean subsurface optical properties obtained from two
space-based lidars: the Cloud-Aerosol Lidar with Orthogonal Polarization
(CALIOP) aboard Cloud-Aerosol Lidar and Infrared Pathfinder Satellite
Observations (CALIPSO) satellite and the Advanced Topographic Laser
Altimeter System (ATLAS) aboard Ice, Cloud, and land Elevation
Satellite-2 (ICESat-2) satellite. Obtaining reliable estimates of
subsurface biomass necessitates removing instrument artifacts peculiar
to each sensor; i.e., polarization crosstalk artifacts in the CALIOP
signals and after pulsing effects arising from the ATLAS photodetectors.
We then validate the lidar retrieved optical properties with
MODerate-resolution Imaging Spectroradiometer (MODIS) ocean color
measurements and autonomous biogeochemical Argo float profiles. Our
results support the continued use of present and future spaceborne
lidars to study the global plankton system and characterize its vertical
structures in the upper ocean.