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Upper ocean structure and circulation and its response to atmospheric forcing

Objective

The major objectives are:
- to relate remote sensing signatures of the Western Mediterranean and seas between Iceland and Norway to upper ocean structure;
- to study the relationship between sea level variability, sea surface temperature features and atmospheric forcing, and the variation in the ocean-atmosphere fluxes of momentum, heat and water vapour across the Tyrrhenian eddy system;
- to use the results of the above studies to help determine experimental strategies.
A multidisciplinary approach combined in situ measurements and remote sensing informations to investigate the Tyrrhenian Sea. Data from a remote sensing aircraft, ship and buoys have been analysed to reveal a cold, cyclonic gyre in the Northern Tyrrhenian with an associated strong front on its southern flank. Good correspondence was found both between remotely sensed and in situ measurements of surface parameters and between surface and subsurface structure. Analysis of satellite and in water measurements outside the intensive phase suggest that the cold gyre is a semipermanent feature whose structure is subject to seasonal variation. Moreover, measurements of air sea radiative fluxes have supplied the first experimental data set over the Tyrrhenian Sea. One of the most interesting results of the air sea interaction experiment was the covariation of sea surface temperature and downwelling long wave radiation in proximity of a marine front. Contemporaneous satellite data have shown a clear correlation between sea surface structures and the horizontal distribution of columnar water content which was one of the major factors responsible for the variation of the atmospheric radiation across the front. Moreover, a comparison between experimental data and results of some empirical formulae was carried out for both atmospheric and solar radiation. The mean difference between the measured and empirical solar radiation values was very small while in the case of atmospheric radiation a very poor agreement was found.
The upper ocean is the energy transfer medium between the overlying atmosphere and the underlying deep ocean. Therefore, the study of phenomena in this layer is fundamental to the understanding of both atmosphere and ocean. The behaviour of the oceanic mixed layer can be significantly modified by mesoscale ocean features such as eddies and fronts, as well as by atmospheric forcing. Seasonal and interannual variations, geographical dependence of upper ocean structure and the eddy field, the extent to which the mesoscale circulation and sea-state affect surface fluxes and how well remotely sensed surface signatures are representative of the deeper ocean, are all the focus of this project.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

TELESPAZIO S.P.A.
Address
Via Tiburtina 965
00156 Roma
Italy

Participants (5)

Ente per le Nuove Tecnologie l'Energia e l'Ambiente (ENEA)
Italy
Address
Via Anguillarese 301
00060 Santa Maria Di Galeria Roma
NATIONAL RESEARCH COUNCIL OF ITALY
Italy
Address
San Polo 1364
30125 Venezia
NATIONAL RESEARCH COUNCIL OF ITALY
Italy
Address
Via Fosso Del Cavaliere 100
00133 Roma
NERC Institute of Oceanographic Sciences
United Kingdom
Address
Deacon Laboratory Brook Road Wormley
GU8 5UB Godalming
UNIVERSITY OF HAMBURG
Germany
Address
Troplowitzstrasse 7
22529 Hamburg