ASE

Air-Sea Exchange

Completed


Type of Structure: coordinated project
Regional Scope: continental in the area: Europe
Parent Organisations: EUROTRAC.EUREKA
Child Organisations:
Duration : 1990 to 1995 COMPLETED
Contact Address: no office contact defined


General information and objectives

  • To assess processes and rates of emission of trace gases in European marine environments.
  • To quantify the production and removal of marine particles and aerosols, and their interaction with atmospheric gases.
  • To describe and budget the dilution, transformation and deposition of trace constituents across the seas.


Highlights of the scientific results
Studies within ASE are yielding information on the dry deposition of trace substances to north European seas. Results include improved estimates of the atmospheric load of nitrogen compounds and sulphur to the North Sea and the inner Danish waters. Corresponding estimates for trace metals are also available.
Emission of biogenic gases from the seas
The ASE activities on biogenic gas emissions have concentrated on the mechanisms behind the emission rates of hydrocarbons, dimethyl sulphide (DMS) and other organo-sulphur compounds in the European seas (North Sea, western Mediterranean) as well as the upstream Atlantic Ocean. A better description of the geographical distribution of these emissions has been obtained, and a strong correlation between the air concentration of DMS and the concentrations of cloud concentration nuclei (CCN) has been found for the clean Atlantic air but not for air masses of continental origin.
The North Sea Experiment
A major campaign for ten ASE groups, studying the chemical composition of aerosols, was the North Sea Experiment in September 1991, involving two research vessels and several coastal stations. The two ships sailed on a circle with one always 200 km upwind of the other, so that changes in pollutant concentrations could be measured as the boundary layer air masses crossed the sea. One result showed that the concentration of nitrogen dioxide, N02, decreased appreciably over the sea where there are no new sources. During the daytime N02 is lost by the reaction with OH radicals, and at night, the reaction with ozone leads to the formation of nitric acid.


Last update: 5/8/22
Source of data: ProClim- Research InfoSystem (1993-2024)

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