http://hdl.handle.net/2122/156 Search the Channel search http://www.earth-prints.org/simple-search http://hdl.handle.net/2122/3815 Title: Using Temperature–Salinity Relations in a Global Ocean Implementation of a Multivariate Data Assimilation Scheme <br/> <br/>Authors: Bellucci, A.; Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna, Italy; Masina, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Di Pietro, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Navarra, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia <br/> <br/>Abstract: In this paper results from the application of an ocean data assimilation (ODA) system, combining a multivariate reduced-order optimal interpolator (OI) scheme with a global ocean general circulation model (OGCM), are described. The present ODA system, designed to assimilate in situ temperature and salinity observations, has been used to produce ocean reanalyses for the 1962–2001 period. The impact of assimilating observed hydrographic data on the ocean mean state and temporal variability is evaluated. A special focus of this work is on the ODA system skill in reproducing a realistic ocean salinity state. Results from a hierarchy of different salinity reanalyses, using varying combinations of assimilated data and background error covariance structures, are described. The impact of the space and time resolution of the background error covariance parameterization on salinity is addressed. Mon, 29 Oct 2007 22:58:59 GMT http://hdl.handle.net/2122/2675 Title: Multi-model multi-method multi-decadal ocean analyses from the ENACT project <br/> <br/>Authors: Davey, M.; Met Office,; Huddleston, M.; Met Office,; Ingleby, B.; Met Office,; Haines, K.; ESSC, reading, UK; Le Traon, P. Y.; CLS, France; Weaver, A.; CERFACS, France; Vialard, J.; LODYC, France; Anderson, D.; ECMWF; Troccoli, A.; ECMWF; Vidard, A.; ECMWF; Burgers, G.; KNMI. Nedelands; Leeuwenburgh, O.; KNMI. Nedelands; Bellucci, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Masina, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Bertino, L.; NERCS, Norway; Korn, P.; MPG-IMET, Germany <br/> <br/>Abstract: in the file Sat, 29 Oct 2005 22:58:59 GMT http://hdl.handle.net/2122/2596 Title: Data assimilation of temperature and salinity profiles in the Adriatic Sea regional model <br/> <br/>Authors: Grezio, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Pinardi, N.; Università di Bologna, Corso di Scienze Ambientali <br/> <br/>Abstract: Temperature and salinity data collected during the October 2002- October 2003 period have been assimilated into a version of the Princeton Ocean Model implemented over the entire Adriatic Sea. The scheme used is SOFA (System for Ocean Analysis and Forecast, DE MEY & BENKIRAN, 2002) and this is the first coastal application of this scheme. The CTD data were collected in 4 coastal areas (Emilia – Romagna Coastal strip, the Gulf of Trieste, the Rovinj and Pelješac-Vis-Drvenik coastal strips) while temperature profiles were acquired with XBT in the southern Adriatic Sea deep ocean areas. The analysis skill scores are examined in order to evaluate the assimilation performance. The results of the assimilation are first compared with independent analyses of satellite Sea Surface Temperature (SST) and it is found that assimilation of profiles improves the SST model estimate. Furthermore, the Root Mean Square (RMS) difference between model and temperature and salinity profiles before data insertion is analysed. The range of RMS temperature error is less than 1 0C for the entire area and decreases with time, indicating a positive impact of the assimilation. The RMS of salinity is less than 1 psu and it also shows a decreasing trend during the assimilation period. Sat, 29 Oct 2005 22:58:59 GMT http://hdl.handle.net/2122/2587 Title: Spatial and temporal structure of Tropical Pacific interannual variability in 20th century coupled simulations <br/> <br/>Authors: Capotondi, A.; NOAA/Earth System Laboratory, CIRES/Climate Diagnostics Center,; Wittenberg, A.; Geophysical Fluid Dynamics Laboratory, Princeton, NJ, United States; Masina, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia <br/> <br/>Abstract: Tropical Pacific interannual variability is examined in nine state-of-the-art coupled climate models, and compared with observations and ocean analyses data sets, the primary focus being on the spatial structure and spectral characteristics of El Nin˜o-Southern Oscillation (ENSO). The spatial patterns of interannual sea surface temperature (SST) anomalies from the coupled models are characterized by maximum variations displaced from the coast of South America, and generally extending too far west with respect to observations. Thermocline variability is characterized by dominant modes that are qualitatively similar in all the models, and consistent with the ‘‘recharge oscillator’’ paradigm for ENSO. The meridional scale of the thermocline depth anomalies is generally narrower than observed, a result that can be related to the pattern of zonal wind stress perturbations in the central-western equatorial Pacific. The wind stress response to eastern equatorial Pacific SST anomalies in the models is narrower and displaced further west than observed. The meridional scale of the wind stress can affect the amount of warm water involved in the recharge/discharge of the equatorial thermocline, while the longitudinal location of the wind stress anomalies can influence the advection of the mean zonal temperature gradient by the anomalous zonal currents, a process that may favor the growth and longer duration of ENSO events when the wind stress perturbations are displaced eastwards. Thus, both discrepancies of the wind stress anomaly patterns in the coupled models with respect to observations (narrow meridional extent, and westward displacement along the equator) may be responsible for the ENSO timescale being shorter in the models than in observations. The examination of the leading advective processes in the SST tendency equation indicates that vertical advection of temperature anomalies tends to favor ENSO growth in all the CGCMs, but at a smaller rate than in observations. In some models it can also promote a phase transition. Longer periods tend to be associated with thermocline and advective feedbacks that are in phase with the SST anomalies, while advective tendencies that lead the SST anomalies by a quarter cycle favor ENSO transitions, thus leading to a shorter period. Sat, 29 Oct 2005 22:58:59 GMT