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Air-sea fluxes

Objectives

This WP aims to obtain the first full annual cycle time series of high-resolution air-sea flux observations of heat, momentum and carbon dioxide. Using these, we want to address the following specific goals:

  1. Estimate the magnitudes of heat, momentum and carbon fluxes exchanged across the sea surface at high-resolution, including obtaining the first estimates in autumn to winter, south of 60°S.
  2. Identify the key temporal and spatial scales of variability of new in situ air-sea flux observations and compare them to widely-used satellite-reanalysis flux products.
  3. Establish how air-sea fluxes are modulated by synoptic storms, ocean dynamics (mixed layer processes, fronts and eddies) and sea ice cover.
  4. Understand the role of surface fluxes (incl. transient storms) and surface sea state (wave-wind interaction) on driving upper ocean processes and stratification (links to WP2 and WP4)
  5. During winter, under the ice, the partial pressure of CO2 is relatively high. We assess the specific contribution to the total annual air-sea carbon flux (in particular, whether there is strong outgassing in spring).
  6. Determine whether the uptake of CO2 south of 60°S is really as low as suggested by some previous studies. The latter may be biased by lack of data and absence of full seasonal data.
  7. Provide estimates of dissipation over the depth of the mixed layer from direct measurements using the Air-Sea Interaction Profiler and relate it to the air-sea fluxes of momentum and CO2.
Tasks
  • Task 1.0: Scientific coordination [Co-Leads: S. Swart (UGOT) and M. Hoppema (AWI)]
  • Task 1.1: Observe air-sea fluxes of heat, momentum and CO2, particularly in autumn and winter [Lead: S. Swart (UGOT); participants: M. Hoppema (AWI), B. Ward (NUIG), J. Boutin (SU), S. Josey (UKRI-NOC), P. Monteiro (CSIR)]
  • Task 1.2: Assess key scales of variability for heat, momentum and carbon air-sea fluxes [Co-Leads: S. Swart (UGOT) and M. Hoppema (AWI); participants: J. Boutin (SU), S. Josey (UKRI-NOC), P. Monteiro (CSIR)]
  • Task 1.3: Determine the uncertainties of satellite-reanalysis air-sea flux estimates of momentum and heat [Co-Leads: S. Swart (UGOT) and S. Josey (UKRI-NOC)]
  • Task 1.4: Determine the role of the ice lid to the annual air-sea flux of CO2 [Lead: M. Hoppema (AWI); participants: J. Boutin (SU), P. Monteiro (CSIR)]
  • Task 1.5: Estimate the contribution of the CO2 air-sea flux of the Weddell region to the total air-sea CO2 flux of the Southern Ocean [Lead: P. Monteiro (CSIR); participants: J. Boutin (SU), M. Hoppema (AWI)]
  • Task 1.6: Estimate dissipation rate of turbulent kinetic energy and relate to the air-sea fluxes. [Lead: B. Ward (NUIG); participants: S. Swart (UGOT), M. Hoppema (AWI)]
Partners

WP co-leaders: S. Swart (UGOT) and M. Hoppema (AWI)

Other participants: B. Ward (NUIG), J. Boutin (SU), S. Josey (UKRI-NOC), P. Monteiro (CSIR)

Workpackages