EurOCEAN 2000 - Vlaams Instituut voor de Zee

RESULTS FROM THE FIRST PROJECT PERIOD (1998-2000):
The planned new instrument developments have been performed succesfully. A sonic
anemometer/thermometer with improved ruggedness and an improved temperature channel has
been produced, as has also a special dedicated sonic temperature unit. Both units have been
through their first field test. The infra- red humidity and CO2 sensors have been constructed and
have gone through laboratory tests. Primary logging soft-ware has been developed and has been
field tested during field cruises in the Arctic. Basic algorithms, relating the measured dissipations
to the relevant fluxes, have been formulated and are awaiting further tests. Extensive field tests
will take place in the remaining project period. Supplementary instruments for the field tests have
been evaluated and response characteristics have been derived and discussed.
All partners in the project generally co-operate and discuss the final products. In the initial phase,
most of the instrument development and construction is performed by partner Gill Instruments
Ltd, that was responsible for the development and construction of the sound based instruments,
and partner KNMI, that is responsible for the Infra Red absorption instruments, providing water
– vapour and CO2 concentrations. Similarly the sound based instruments are used for measuring
wind velocity and temperature.
The main responsible partners for development of the logging soft–ware and algorithm
development are Southampton Oceanography Centre and Centre d’Etude Environments
Terrestres et Planetaire. The algorithms within the project are integrated into a software packet
that convert the directly measured turbulence parameters to the fluxes of momentum, heat, water
vapour and CO2 that are is the final output of the AutoFlux system, together with time and space
coordinates and some estimates on reliability. As such the algorithms will include the current
scientific consensus about the relations between different aspects of the turbulence fields in the
marine atmospheric surface boundary layer.
Risoe and Uppsala University are responsible for the initial field tests, that primarily take place
off the coast of the Swedish island, Gotland. Also field test from scientific ship cruises have
taken place and will continue for the rest of the project period , mostly conducted by
Southampton Oceanography Centre. The Risø group has simultaneously been working perfecting
the measuring systems and methods in order to be able to measure the CO2 fluxes
simultaneously with an independent method involving both eddycorrelation and equilibrator
measurements. A problem with testing CO2 measurements is that at present there is no generally
accepted method for obtaining the ‘ true’ flux.
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