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The Role of the Oceanic Thermal Skin as a Modifier of CO2 Uptake

OCCI Project Funded: 2004

Proposed Research

What are the primary questions you are trying to address with this research?
This project focuses on the influence of small-scale effects on the global air-sea flux of CO2. Within the upper millimeter of the ocean, there is a large temperature gradient, leading to the so-called oceanic thermal skin effect where the temperature at the ocean surface is cooler than the water below. This can play a large role in the air-sea exchange of CO2 through the sensitivity of the solubility of CO2 to temperature.

What is the significance of this research for others working in this field of inquiry and for the broader scientific community?
The oceans are the largest absorber of atmospheric CO2. One of the most urgent requirements in current climate research is the accurate determination of the global oceanic uptake of CO2. Sources and sinks of CO2 vary across the globe on a seasonal to annual basis. Knowledge of the rate of CO2 transfer will allow us to make predictions of future climate with greater confidence. This project aims to improve estimates of CO2 uptake by incorporating the skin effect into CO2 flux relationships.

What is the significance of this research for society?
The societal relevance of this project is through an increased understanding of some of the processes responsible for enhancing oceanic uptake of CO2, which constitutes the highest percentage of all greenhouse gases.

When and where will this investigation be conducted??
The compilation of a database with coincident in-situ radiometric skin temperatures and pCO2 data has been undertaken, and some preliminary results of this analysis were presented at the Ocean Sciences Meeting in January 2004. These funds will allow us to complete the analysis and determine the extent to which the skin effect is responsible for influencing the estimate of the global CO2 fluxes. This analysis will be conducted over the coming year, and will culminate with a paper in a scientific journal.

What are the key tools or instruments needed to conduct this research?
The data has been acquired, and so the only tool required is a computer for the data analysis. Matlab will be used extensively for this project.

What are the greatest challenges – physical or intellectual – to conducting this investigation?
The greatest challenge in oceanographic research is going to sea and making measurements. The data for this project has come from 12 measurement campaigns, and provides extensive coverage over the Northern Hemisphere. Unfortunately, there is scant coverage in the Southern Oceans (see map show cruise track lines), where there exists the greatest uncertainties in the oceanic uptake of CO2. One of the biggest challenges is this research will be to develop a model that accurately reflects the skin effect on a global basis. However, it will provide some constraints on the current estimates of the skin effect.

Is this research part of a larger project or program?
This project is relevant to the International SOLAS (Surface Ocean Lower Atmosphere Study) initiative which has as its goal to quantify biogeochemical–physical atmosphere–ocean interactions and determine how this coupled system affects climate and environmental change. One of the key objectives is accurate quantification of air–sea gas transfer rates.

If you have conducted previous/similar work on this subject, please suggest any web links or citations that might help others better understand the background to your line of research. If appropriate and readily available, please suggest or provide photographs, illustrations, tables, and charts, as well.
Preliminary results for this project were presented at the Ocean Sciences Meeting, in January 2004. Please see linked schematic 04ward2.pdf. Below is the map which shows the cruise track lines from which this data is used. Further information on my research can be found at: http://www.whoi.edu/science/AOPE/people/bward/

Originally published: January 1, 2004