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Research aims of DOGEE II
Cruise:
Our understanding of air-sea gas exchange has advanced rapidly over the
past decade but we remain unable to adequately parameterise fundamental
controlling processes. For some gases, such as CO2,
this constitutes the dominating uncertainty in global budgeting.
The goal DOGEE-SOLAS therefore, is to
reduce the uncertainty by identifying and evaluating these major
controlling processes. Project outputs will enable more accurate
parameterizations of gas exchange and facilitate scaling across a range
of gases of interest. Two dedicated cruises will be carried out in
the north Atlantic to examine the roles of wind speed, sea state,
surface slicks and other sea surface turbulence-related phenomena.
Both direct and indirect gas flux measurements will be made using
well-established and new methods, in both water and air.
The scientific objectives of the cruise
are:
- Dual-tracer (3He and SF6)
releases in the north Atlantic. One release will involve
two patches in close proximity; one labelled with N-acetyl-D-glucosamine
to mimic the role of surface organic slicks in gas transfer.
- To record (by video) and measure (by
capacitance wave wires) whitecap coverage and wave breaking, and to
develop an improved parameterisation.
- To quantify acoustically, bubble
populations produced by breaking waves.
- To measure wind speed, air temperature
and humidity, sea surface temperature. IR surface temperature,
downwelling long- and short-wave radiation and air pressure.
- To measure air-sea fluxes of CO2,
sensible heat, latent heat and momentum (EC and inertial dissipation)
with an automated sensor array.
- To measure DMS fluxes (by GF and REA)
and scale theme to other gases based on diffusivity.
- To quantify flow distortion biases in
the data using Computation Fluid Dynamics.
- To deploy a sampling system for
collecting sea surface microlayer samples.
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