Development and Validation of the CALIPSO Ocean Subsurface Data Record

Yongxiang Hu1, Michael Behrenfeld2, Chris A Hostetler1, Johnathan W Hair1, Xiaomei Lu1, Sharon D Rodier3, James H Churnside4 and William H Hunt1, (1)NASA Langley Research Center, Hampton, VA, United States, (2)Oregon State University, Corvallis, OR, United States, (3)Science Systems and Applications, Inc. Hampton, Hampton, VA, United States, (4)NOAA Boulder, Boulder, CO, United States
Abstract:
Over the life of the CALIPSO mission, the stability of the CALIOP depolarization ratio calibration has remained within 1%. CALIOP’s highly stable depolarization ratio measurements can be used for studying changes in phytoplankton backscatter and carbon biomass (Behrenfeld et al., 2013). Using the depolarization ratio measurements from CALIOP together with collocated A-Train measurements (such as the ocean surface backscatter cross section derived from CloudSat ocean surface backscatter measurements, AMSR-E/AMSR-2 wind speeds, and MODIS diffuse attenuation coefficients), we have developed innovative retrieval methods that translate the CALIOP ocean subsurface signals into the following optical and physical properties (Behrenfeld et al., 2013; Lu et al., 2014; Hu et al., 2015):

• the cross polarization component of the column integrated ocean subsurface backscatter signal;

• the particulate backscatter coefficient (bbp);

• the depolarization ratio of ocean subsurface backscatter; and

• the ocean subsurface beam attenuation coefficient.

These new CALIOP data products can provide a wealth of unique information to complement existing ocean color measurements, including nighttime measurements, measurements underneath aerosols and non-opaque clouds, measurements in polar regions during all seasons and near sea-ice, and direct measurements of beam attenuation coefficients. We therefore plan to

1) evaluate and improve the retrieval algorithms using high vertical resolution airborne HSRL ocean profiling observations together with in situ ship measurements acquired during two recent field campaigns (Azores and SABOR) and the upcoming NAAMES (the North Atlantic Aerosols and Marine Ecosystems Study) Earth Venture suborbital mission;

2) assess the uncertainty of the retrieved properties using the field campaign measurements, as well as the existing and upcoming 30° off-nadir CALIOP measurements; and

3) produce the first ever CALIOP ocean subsurface data product.

We will introduce the theoretical basis of the theoretical basis of the algorithms and progress in data production, and present the preliminary results of the validation studies.

Back to: Lidar, Aircraft, and Satellite Retrievals of Ecological and Physical Processes in the Ocean I