Theme 1: Greenhouse gases and the oceans


Introduction

Carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) are the most significant long lived greenhouse gases (GHGs) after water vapour. Physical and biogeochemical processes in the surface ocean play an important role in controlling the ocean-atmosphere GHG fluxes. Understanding the sensitivities of these processes to climate and environmental change is of critical importance for the mitigation of climate change.

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Figure 1: Processes and impacts/stressors associated with long-lived greenhouse gases.

Theme 1 team

Team leaders:
Parvadha Suntharalingam (United Kingdom, p.suntharalingam@uea.ac.uk)      
Guiling Zhang (China, guilingzhang@ouc.edu.cn)
 
Team members:
Hermann Bange (Germany, hbange@geomar.de)
Dorothee Bakker (United Kingdom, d.bakker@uea.ac.uk)
Tom Bell (United Kingdom, tbe@pml.ac.uk)
Minhan Dai (China, mdai@xmu.edu.cn)
Sam Wilson (United States, stwilson@hawaii.edu)

Research questions

Key questions to be addressed within this theme are:

  • Which surface ocean processes control GHG cycling at regional to global scales?
  • What are the main feedback mechanisms between climate change and oceanic GHG emissions?
  • How can we assess future oceanic fluxes of GHGs in a changing ocean and atmosphere?

Priorities

Detailed regional analyses
To better quantify and predict the evolution of oceanic GHG budgets and air-sea fluxes, detailed analyses of key regions for GHG fluxes are required. These include the Southern Ocean, coastal zones, and oceanic Oxygen Minimum Zones. Recommended approaches include higher resolution numerical models which represent the coupling of key processes for circulation, ecosystems and relevant biogeochemistry, and detailed biogeographical sampling of marine ecosystems across gradients to characterise the variations in environmental drivers and GHG flux responses.

Increased density of observations
In order to reliably assess variations in GHG fluxes within the ocean and across the air-sea interface, a denser observing system is required; e.g. from ships, autonomous platforms (e.g., Argo floats, gliders), and moorings. Satellite observations of relevant marine ecosystem and oceanic properties should also be exploited and linked systematically to in-situ oceanic measurements.

Development of new analysis tools and extension of existing methodologies
Improved quantification of ocean-atmosphere carbon dioxide fluxes has been achieved by combining existing particulate carbon dioxide surface data with a range of mapping methods including spatial interpolation, multi-variate regressions and neural network analyses. These tools can be extended to the other GHGs to improve flux quantification and to further investigate the key underlying processes.  

Planned activities

Workshop on Dissolved N2O and CH4 measurements
This workshop will be organized by SCOR WG#143 as a final meeting. The purpose is to establish framework for an N2O and CH4 ocean time series network and write a global oceanic N2O/CH4 summary paper for publication, make comparison of standard gases, intercompare underway equilibrator systems and N2O and CH4 measurements of discrete seawater samples.
Location: Portland, USA
Dates: February 10, 2018
Chairs: Hermann Bange and Sam Wilson

Nationally funded research programs on regional ocean-atmosphere GHG fluxes
Current nationally-funded programs investigating ocean CO2 uptake in the Southern Ocean include the US National Science Foundation’s “Southern Ocean Carbon and Climate Observations and Modeling” (SOCCOM) project, and the UK National Environmental Research Council funded “Role of the Southern Ocean in the Earth System” (RoSES). Information on planned observational programs and workshops can be found via the respective program websites:
SOCCOM: https://soccom.princeton.edu/
RoSES:  http://www.nerc.ac.uk/research/funded/programmes/roses/
 
Carbon Group
Following the successes of the joint SOLAS/IMBER Carbon groups (SIC) a new Carbon Group is being formed jointly sponsored by IMBER, SOLAS, IOCCP, GCP, CLIVAR, and WCRP.



- last update April 2018 -