Behrenfeld, Michael: Oregon State University (Project Lead)
Project Funding:
2014 - 2016
NRA: 2013 NASA: Terra and Aqua: Algorithms--Existing Data Products
Funded by NASA
Abstract:
This research project will advance understanding of global ocean phytoplankton carbon standing stocks and physiology and how these key properties vary with climate forcings. Historically, chlorophyll concentration has functioned as the primary parameter retrieved from space that is related to phytoplankton abundance in the upper ocean. The relationship between phytoplankton biomass and chlorophyll concentration, however, is highly variable. Indeed, laboratory studies indicate that phytoplankton Chl:C ratios can vary by nearly 2 orders of magnitude in response to changing light, temperature, and nutrient conditions. This physiological imprint on chlorophyll concentration compromises our ability to interpret satellite-observed variability in global chlorophyll distributions in terms of net primary production and organic carbon export to depth (which influences atmosphere-to-ocean CO2 transfer). However, recent developments in ocean color data analyses have provided a path for assessing phytoplankton carbon biomass from retrieved particulate backscattering coefficients, concurrently opening a door for characterizing global phytoplankton physiology. The current research project builds on this foundation, with 5 primary activities:

1. Employment of new field data on phytoplankton carbon concentrations to create global validated phytoplankton carbon products from MODIS-Aqua
2. Field- and satellite-based re-evaluation of light-driven changes in phytoplankton Chl:C to establish an appropriate photoacclimation response relationship for application to MODIS-Aqua data
3. Refinement of ocean color inversion retrievals of particulate backscattering coefficients through integration of new data from the CALIOP sensor
4. Uncertainty analysis of MODIS-Aqua phytoplankton carbon and Chl:C products
5. Application of results to the ocean color data record to evaluate climate-driven variability in surface ocean plankton ecosystems.
This work is thus directly relevant to NASA's broad science objective of understanding how and why the Earth system is changing and, through observations of contemporary ocean variability, will provide insight on future Earth system change. The focal satellite remote sensing data used during this investigation will be ocean color observations from the MODIS-Aqua sensor, making this project responsive to component 2.1 'Science Data Analysis' under the solicited research topics for ROSES-2013 The Science of Terra and Aqua Program Element. In addition, changes in phytoplankton carbon and physiology documented by the MODIS-Aqua time-series will be viewed in the context of the ocean color record initiated by the SeaWiFS and currently including the VIIRS. Our project also utilizes new ocean retrievals from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) sensor on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite, a component of the A-train Earth Observing Sensor suite. This inclusion of diverse remote sensing data products makes this proposed study also responsive to The Science of Terra and Aqua Subelement 2.1.1, 'Multiplatform and Sensor Data Fusion'.
More details may be found in the following project profile(s):
