OCEANOLOGICA ACTA - VOL. 21 - No3 / Oceanic response to atmospheric forcing derived from different climatic data sets. Intercornparison study for the Black Sea Joanna V. STANEVA, Emil V. STANEV Department of Meteorology and Geophysics, Faculty of Physics, University d Sofia, 5, James Bourchier street, 1126 Sofia, Bulgaria (Received 24106196, revised 20/06/97, accepted 27106198) Abstract - Available climatic and atmospheric analysis data have been used to prepare forcing functions for the Black Sea numerical model, based on the Bryan-Semtner-Cox Modular Ocean Model and including parameterizations for the atmos- phere-ocean exchange, inflow through the strait of Bosphorus and the Mediterranean plume. Atmospheric data from dif- ferent sources are compared and the drawbacks of some of them illustrated. A new wind stress data set, based on ship observations, is prepared. Compared to the existing wind stress estimates, the present ones use additional data and more accurate parameterization of the boundary layer physics. The intercomparison between forcing data sets is focused on the heat flux and freshwater flux at the sea surface. The model simulates adequately vertical stratification, seasonal variability and horizontal patterns. Five data sets for heat flux, freshwater flux and wind stress are used in different combinations to study the model response. The large differences between the simulations, forced by different wind stress and identical thermohaline forcing, justify the computation of the new wind stress. Though the forcing data used are perhaps close to the best available at the moment for the Black Sea, the model simulations range in large intervals and some of them are very poor. The model responses to forcing functions of different origin give rough estimates on the possible errors in present-day simulations. Some inconsistencies give clear indications that further verifications, improvements of the forcing functions, and intercomparisons between the responses simulated by the ocean circulation models are needed. 0 Elsevier, Paris Black Sea I water exchange I heat exchange I wind stress I numerical modelling RCsumi5 - R&ponse de 1’ocCan au forcage atmosphbique en mer Noire. Des don&es climatiques et atmospheriques de la litterature ont &C utilisees pour determiner les fonctions de forcage dans une modelisation numerique de la mer Noire. Fond& sur le modble modulaire de l’ocean de Bryan-Semtner-Cox, le present modele prend en compte les &changes entre l’ocean et l’atmosphere, l’apport par le detroit du Bosphore et le panache mediterraneen. Des donnees atmospheriques de differentes origines sont compartes et leurs defauts eventuels sont indiques. Une representation plus precise de la couche- limite est obtenue en considerant un nouveau parametre, la tension du vent, fournie par des observations de navires. La comparaison des series de donnees Porte sur les flux de chaleur et d’eau deuce a travers la surface libre. Le modble repre- sente correctement la stratification verticale, la variabilite saisonniere et les repartitions horizontales. Cinq series de don- trees, pour le flux #de chaleur, le flux d’eau deuce et la tension de vent, sont utilisees dans differentes combinaisons afin d’etudier la rdponse du modble. Avec plusieurs tensions de vent et un mCme forcage thermohalin, de grandes differences apparaissent entre les simulations, justifiant le calcul de la nouvelle tension de vent. Bien que les donnees utilisees pour le forcage soient probablement parmi les meilleures actuellement disponibles pour la mer Noire, les resultats se situent dans de larges intervalles et certains modeles sont plutot mtdiocres. Le modele donne une estimation des erreurs que l’on peut attendre ldans le cadre des modbles forces par des donnees actuelles. Des incoherences entre differentes simulations mon- trent la necessite de verifications, ameliorations des forqages et intercomparaisons de resultats. 0 Elsevier, Paris mer Noire I &change d’eau I Cchange de chaleur I tension du vent I modClisation numdrique Oceanologica Acta 13399 1784/98/03/O Elsevier, Paris 393