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| FETCH experiment, Mediterranean Sea, 1998
"Flux, Etat de la mer et Télédétection
"Fluxes, sea state and remote sensing
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This unofficial web page provides a summary in English of the 1998 FETCH experiment. For detailed information on the experiment, along with access to data, see the official FETCH web site (in French). The primary scientific results arising from FETCH will be published shortly in a special section in the Journal of Geophysical Research-Oceans.
The FETCH experiment involved the participation of scientists from the following (and other) laboratories:
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The primary funding for FETCH was provided by the EU:
Scientific Goals: The FETCH experiment was aimed at studying the physical processes associated with air/sea exchanges, and mesoscale oceanic circulation in a coastal region dominated by frequent strong offshore winds. The experiment took place in March-April 1998 in the northwestern Mediterranean Sea (Gulf of Lions).During this early spring period, meteorological conditions at the experimental site are characterized by frequent events of strong offshore winds: the northerly Mistral and northwesterly Tramontane.These strong, orographically forced, winds have important consequences for the circulation and mixing of the Mediterranean Sea.The specific objectives of FETCH, as outlined in Hauser et al (2002
- see reference list below) are as follows:
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Map of FETCH domain. B and B' indicate buoy positions. |
1) to develop and assess the methods of estimating turbulent fluxes of heat and momentum at the air/sea interface, and to analyze the turbulent and radiative fluxes in coastal conditions and their relation with the atmospheric boundary layer;
2) to document and analyze the evolution of the wave field in coastal (but deep-water) conditions, including fetch-limited situations, and to analyze the impact of sea-state on the turbulent fluxes;
3) to improve the inversion algorithms and use of remote-sensing measurements to describe the air/sea interface in general and in particular in coastal conditions;
4) to better describe the dominant factors of the ocean circulation
in the Gulf of Lions and to develop the corresponding numerical modeling.
Platforms and Instrumentation:
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The 85m research vessel L'Atalante (at left, without its FETCH mast) was equipped to measure: turbulent fluxes of momentum, heat and water vapour, radiative fluxes, mean meteorological parameters, atmospheric profiles (via radiosondes), aerosols, DMS, whitecap coverage, ADCP current profiles and hydrographic parameters (via CTD casts and a thermosalinograph). The ship operated in the FETCH area from 13-29 March and 1-15 April. |
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An ASIS (Air-Sea Interaction Spar) buoy was deployed at point B (see above map) on 18 March and remained on site until 9 April. The buoy was equipped to measure the turbulent momentum flux (via eddy correlation), along with mean meteorological parameters, and directional wave spectra. In addition, an ADCP measured currents in the lower water column. |
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Two wave rider buoys were deployed during FETCH. A directional waverider (left) was deployed at point B (see map) on 16 March, and later moved to point B' (25 March) where it remained until recovery on 11 April. The buoy measured directional wave spectra and SST. A non-directional waverider was deployed from the L'Atalante, and collected 1D wave spectra while drifting. |
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The Merlin-IV, operated by Météo-France, carried the RESSAC C-band radar, with a conical scanning antenna (visible below the aircraft at left). The radar measured directional wave spectra, along with surface winds and atmospheric parameters. |
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The Fokker-27 "ARAT" (Avion de Recherche Atmosphérique et de Télédétection), operated by INSU, carried the downward looking lidar "LEANDRE2" designed for profiling water vapour concentrations in the lower atmosphere. Mean atmospheric parameters, along with aerosols, and ozone were also measured. |
Data from several satellites (ERS-2, TOPEX-POSEIDON, SSM/I, Meteosat) were archived, and are available on the official FETCH website. Finally, considerable efforts were put into modelling of the FETCH and surrounding domains: atmospheric (ECMWF, ARPEGE, ALADIN), and wave (WAM, VAG) models were run on a variety of grid-scales.
FETCH journal publications
[Notes: Manuscripts listed as in press with J. Geophys. Res. will be published in a special section during 2002. For a complete list of FETCH publications, including reports, theses and conference proceedings, see the official FETCH website ]
Delahaye J-Y., C. Guérin, J.P. Vinson, H. Dupuis, A. Weill, H. Branger, L. Eymard, G. Lachaud , J. Lavergnat and G. Lachaud, A new shipborne microwave refractometer for estimating the evaporation flux at the sea surface, J. Atmos. Ocean. Technol., 18, 459-575, 2001
Drennan, W.M., H.C. Graber, D. Hauser and C. Quentin, 2002: On the wave age dependence of wind stress over pure wind seas. J. Geophys. Res. , 10.1029/2000JC00715, [in press].
Dupuis, H., C. Guerin, D. Hauser, A. Weill, P. Nacass, W. Drennan, S. Cloché and H. Graber, 2002: Impact of flow distortion
corrections on turbulent fluxes estimated by the inertial dissipation method during the FETCH experiment on R/V L'Atalante, J. Geophys. Res., 10.1029/2001JC01075, [in press].Estournel C. , X. Durrieu de Madron , P. Marsaleix , F. Auclair , C. Julliand and R. Vehil, 2002: Observation and modelisation of the winter coastal oceanic circulation in the Gulf of Lions under wind conditions influenced by the continental orography (FETCH experiment) , J. Geophys. Res.,10.1029/2001JC00825, [in press].
Eymard L. , D. Bourras , J.M. Lefèvre , P. Le Borgne and C. Guérin , 2002: Comparison of surface fluxes from meteorological models, satellites and ship during the FETCH experiment, J.Geophys. Res., 10.1029/2001JC1207, [in press].
Flamant, C., 2002: Alpine lee cyclogenesis on air-sea heat exchanges and marine atmospheric boundary layer thermodynamics over the Western Mediterranean during a Tramontane/mistral event, J.Geophys. Res., 10.1029/2002JC01040, [in press].
Flamant C., J. Pelon, L. Eymard, and J. Tournadre, 2002: Intercomparison of SSM/I and NWP model retrievals of integrated water vapor content with ship and airborne remote sensing measurements in the coastal. J.Geophys. Res., 10.1029/2002JC01068, [in press]
Graber, H.C., E.A. Terray, M.A. Donelan, W.M. Drennan, J. Van Leer and D.B. Peters, 2000: ASIS -- A new air-sea interaction spar buoy: design and performance at sea. J. Atmos. Oceanic Tech. 17, 708-720.
Hauser D., H. Branger, S. Bouffies-Cloché, S. Despiau, W. Drennan, H. Dupuis, P.Durand, X. Durrieu de Madron, C. Estournel, L. Eymard, C. Flamant, H. Graber, C. Guérin, K. Kahma, G. Lachaud, J-M. Lefèvre, J. Pelon, H. Pettersson, B. Piguet, P. Queffeulou, D. Tailliez, J. Tournadre and A. Weill, 2002: The FETCH experiment: an overview, J. Geophys. Res., 10.1029/2001JC01202, [in press]
Hauser D., H. Dupuis, X. Durrieu de Madron, C. Estournel, C. Flamant, J. Pelon, P. Queffeulou, La Campagne FETCH: Etude des échanges océan/atmosphère dans les conditions côtières du Golfe du Lion, 2000: La Météorologie, 8è série, 14-31.
Kudryavstev V., D. Hauser, G. Caudal, and B. Chapron, 2002: A semi-empirical model of the normalized radar cross-section of the sea surface. Part I: The background model, J. Geophys. Res., 10.1029/2001JC01003, [in press]
Kudryavstev V., D. Hauser, G. Caudal, and B. Chapron, 2002: A semi-empirical model of the normalized radar cross-section of the sea surface. Part II: Radar modulation Transfer Function, J. Geophys. Res., 10.1029/2001JC01004, [in press]
Massouh, L., O. Lecalvé and S. Despiau, 1999 : Measurement of whitecap coverage during FETCH 98 experiment, J. Aerosol. Sci., 30, suppl.1, S177-S178.
Pettersson, H., H.C. Graber, D. Hauser, C. Quentin, K.K. Kahma, W.M. Drennan, and M.A. Donelan, 2002: Directional wave
measurements from three wave sensors during the FETCH experiment, J. Geophys. Res., 10.1029/2001JC01164, [in press].Sellegri, K., J. Gourdeau and S. Despiau, 1999: Chemical composition of marine aerosol in the Mediteranean coastal zone during the FETCH Campaign, J. Aerosol. Sci., 30, suppl.1, pp.S7-S8.