Strutton, Pete: Oregon State University (Project Lead)
Project Funding:
2007 - 2010
NRA: 2006 NASA: Ocean Biology and Biogeochemistry
Funded by NASA
Abstract:
The Southern Ocean represents a vast gap in our understanding of global air-sea CO2
fluxes. We propose a data synthesis effort, incorporating model-generated transport
fields, to provide satellite-based maps of pCO2 with superior spatial and temporal
coverage compared to the current climatologies produced by interpolation of sparse in
situ observations. These maps will serve two important purposes: (1) they will
significantly improve our estimates of regional and total CO2 fluxes, and (2) they will
serve as a validation products for current and future models of Southern Ocean
biogeochemistry.
Our approach consists of four steps:
1. Objective identification of provinces. Predictions of pCO2 will be more accurate if we
develop a suite of regional (and perhaps seasonal) algorithms rather than one algorithm
for the entire Southern Ocean. Satellite measurements of SST, chlorophyll, wind stress
and sea surface height can be used to determine regions of the ocean that are similar with
respect to their physics and biology via a self-organizing map (SOM) analysis.
2. Develop regional algorithms for pCO2. We will use techniques such as multiple linear
regressions applied in biogeochemical regimes defined by the SOM analyses to relate
pCO2 to remotely observable parameters such as SST, chlorophyll and sea surface height.
3. Develop improved, model-based interpolation schemes for sparse data. While the
MLR/SOM approach has shown promise, it is purely empirical and lacks clear
mechanistic underpinnings. By incorporating the sparse observations with modelgenerated
surface flow fields and remote sensing data, we can parameterize the historical
forcing experienced by any water mass with observed pCO2. These historyparameterizations
and pCO2 observations can be used for further algorithm development,
which can then be applied to any location with remote sensing data and modeled flowfields
to predict pCO2 distributions at greatly improved spatial and temporal resolution.
4. Calculation of air-sea CO2 fluxes. Maps of Southern Ocean pCO2 produced by
application of these algorithms can be combined with satellite winds to calculate the airsea
CO2 flux. Southern Ocean GasEx is specifically aimed at improved parameterizations
of the gas transfer velocity as a function of wind speed for the Southern Ocean. This
enhanced understanding, combined with significantly improved maps of pCO2 will
provide calculations of Southern Ocean CO2 fluxes with unprecedented accuracy and
coverage.
Connection to modeling
Considerable research effort is currently directed towards quantifying Southern Ocean
bio-geochemistry. Phytoplankton biomass can be validated by satellite chlorophyll, but
there are no comparable data sets for primary productivity, carbon export or pCO2.
Surface maps of air-sea CO2 flux would serve as valuable validation products for
modeled CO2 flux, and would also provide perhaps the best indication of the accuracy of
modeled productivity and export.
2008 NASA Carbon Cycle & Ecosystems Joint Science Workshop Posters
- Remote sensing of Southern Ocean air-sea CO2 fluxes
-- (Peter Strutton, Burke Hales)
[abstract]
More details may be found in the following project profile(s):
