Project Funding: 2013 - 2015

NRA: 2012 NASA: Ocean Biology and Biogeochemistry   

Funded by NASA

Abstract:
The Cloud-Aerosol Lidar with Orthogonal Polarization on the CALIPSO satellite has shown that ocean subsurface retrievals are possible from space. However, the CALIOP instrument was not designed for ocean profiling and has limitations for this application. International interest in space-based ocean lidar measurements is increasing and proposals targeting ocean retrievals were recently submitted to ESA (The Green and Blue Carbon Budget Investigation by Lidar) and NASA (Ocean Profiling and Atmospheric Lidar - OPAL). Our team at NASA Langley Research Center is modifying our airborne High Spectral Resolution Lidar (HSRL-1) under the NASA Airborne Instrument Technology Transition Program to provide measurements that can be used to demonstrate the potential of a space-based HSRL such as OPAL. Our studies show that such measurements can penetrate through up to 70% of the ocean euphotic zone to characterize biomass features far out of reach of traditional passive sensors and would therefore dramatically enhance the accuracy of global plant biomass and carbon estimates. We therefore propose to deploy the modified HSRL-1 instrument together with the NASA GISS Research Scanning Polarimeter (RSP) in order to address element 2.2 (p. A.3-3) of the announcement of opportunity, New and/or Multisensor Data Analyses and Approaches of Ocean Biology and Biogeochemistry Objectives . Project elements will include 1. Collocated aircraft HSRL /RSP and ship-based optical measurements 2. HSRL/RSP backscatter and beam attenuation modeling and algorithm studies 3. Assessment of the scientific impact of a future spaceborne lidar and polarimeter mission The focus of the project is to develop and validate algorithms for the retrieval of these coefficients in anticipation of new satellite sensors and multi-sensor approaches. The airborne HSRL-1 instrument will provide attenuated backscatter and Brillouin backscatter data from which vertically resolved profiles of subsurface particulate backscatter and light attenuation can be retrieved. The particulate backscatter profile can be used to estimate hemispheric backscatter from phytoplankton, bbp, and the attenuation profile can be used to estimate the diffuse attenuation coefficient, Kd. The multi-angle, multi-wavelength polarized RSP observations provide a tie to passive estimates from past and future ocean color radiometers together with estimates of absorption by colored dissolve organic matter that will provide a context for the HSRL-1 retrievals. To evaluate and assess the scientific impact of the HSRL-1 and RSP retrievals the remote sensing measurements will be made along the tracks of a cruise conducted for the The Phytoplankton Carbon Project (hereafter referred to as the Carbon Project ; Professor Michael Behrenfeld, PI) that is currently funded under NASA s Carbon Monitoring System (CMS) program. Research vessels deployed on this project are outfitted with the in situ optical sensors required to validate the retrievals that we will develop on this project. We will work with the Carbon Project team to design flights coordinated with Carbon Project cruise in 2014 and use the in situ optical data acquired on that cruise to assess and improve the lidar and polarimeter retrievals.

2015 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Forest Canopy Height Estimation from Calipso Lidar Measurement   --   (Xiaomei Lu, Yongxiang Hu)   [abstract]

More details may be found in the following project profile(s):

• NASA Ocean Biology & Biogeochemistry (OBB) Project Profile