http://hdl.handle.net/2122/153 Search the Channel search http://www.earth-prints.org/simple-search http://hdl.handle.net/2122/3819 Title: A numericla study of the mescale variability in the Adriatic Sea <br/> <br/>Authors: Oddo, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Pinardi, N.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia <br/> <br/>Abstract: The Adriatic Sea mesoscale and its inter-annual variability is investigated by means of a high-resolution numerical ocean model with approximately 2 km resolution. The ocean model used is based on the Princeton Ocean Model (POM, Blumberg and Mellor 1987) which has been modified in the advection scheme and the vertical velocity surface boundary condition. The simulation spans 6 years starting from January 1999 till December 2004. The surface forcing is interactively computed using European Centre for Medium Range Weather Forecast (ECMWF) operational atmospheric fields and climatological precipitation, while river runoff is obtained combining daily Po river (the main Adriatic river) data together with climatological estimates for all the other rivers. The model results have been validated by an extended comparison with in situ and remote sensing observations. The simulated variability exhibits evident similarities with the actual mesoscale variability, in terms of location, nature and temporal evolution of the features. The major results concern the spatial and temporal variability of Eddy and Mean Kinetic Energy (EKE and MKE) and the baroclinic energy conversion term contained in the buoyancy work time rate. We show for the first time evidence of baroclinic instability at the level of major sub-basin scale structures such as the Western Adriatic Coastal Current. Furthermore, the seasonal and inter-annual variability of mean and eddy kinetic energy is correlated with surface forcing (wind stress work) and Po runoff. http://hdl.handle.net/2122/3799 Title: Comparison of Marine Insolation Estimating methods in the Adriatic Sea <br/> <br/>Authors: Do-seong, B.; Ocean Research Laboratory, National Oceanographic Research Institute, Incheon 400-800, Korea; Pinardi, N.; 2Alma Mater Studiorum Università di Bologna, Centro Interdipartimentale per la Ricerca sulle Scienze Ambientali <br/> <br/>Abstract: We compare insolation results calculated from two well-known empirical formulas (Seckel and Beaudry’s SB73 formula and the original Smithsonian (SMS) formula) and a radiative transfer model using input data predicted from meteorological weather-forecast models, and review the accuracy of each method. Comparison of annual mean daily irradiance values for clear-sky conditions between the two formulas shows that, relative to the SMS, the SB73 underestimates spring values by 9 W m-2 in the northern Adriatic Sea, although overall there is a good agreement between the annual results calculated with the two formulas. We also elucidate the effect on SMS of changing the ‘Sun-Earth distance factor ( f )’, a parameter which is commonly assumed to be constant in the oceanographic context. Results show that the mean daily solar radiation for clear-sky conditions in the northern Adriatic Sea can be reduced as much as 12 W m-2 during summer due to a decrease in the f value. Lastly, surface irradiance values calculated from a simple radiative transfer model (GM02) for clear-sky conditions are compared to those from SB73 and SMS. Comparison with in situ data in the northern Adriatic Sea shows that the GM02 estimate gives more realistic surface irradiance values than SMS, particularly during summer. Additionally, irradiance values calculated by GM02 using the buoy meteorological fields and ECMWF (The European Centre for Medium Range Weather Forecasts) meteorological data show the suitability of the ECMWF data usage. Through tests of GM02 sensitivity to key regional meteorological factors, we explore the main factors contributing significantly to a reduction in summertime solar irradiance in the Adriatic Sea. http://hdl.handle.net/2122/3796 Title: Biogeographic validation of a global ocean biogeochemical model <br/> <br/>Authors: Vichi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Allen, J. I.; PML, UK; Hardman-Mountford, N.; PML, UK <br/> <br/>Abstract: Currently biogeochemical models of the global ocean focus on simulating the coupling between prevalent physical conditions and the biogeochemical processes with the underlying assumption that coherent biological properties are a direct (or modulated) response to physics. This is one possible biogeographic characterisation of the pelagic environment, since biogeochemistry represents only one aspect of marine ecosystems. Several models are currently capable of simulating the chlorophyll distribution observed from space, though an objective validation with respect to relevant ecosystem properties is still lacking. In this paper we analyse the results of one of the most comprehensive models of ocean biogeochemistry with an emphasis on biogeographic validation sensu Longhurst (Ecological Geography of the Sea, 2007, 2nd edition, Academic Press). A set of multivariate statistical tools, Multi Dimensional Scaling (MDS) and Principal Components Analysis (PCA), are used to verify the existence of pre-defined biogeographic provinces and their statistical significance. The MDS ordination indicates that the given provinces are recognizable in the model on the basis of the selected variables. Analysis of Similarity (ANOSIM) shows that the provinces are statistically separable and they can be more easily distinguished in terms of their environmental features rather than their biology. The underlying relationships between the physical and biological properties are investigated through correlation analyses, thus providing some insights on how the model reproduces features characteristic of the various regions. Satellite chlorophyll data have been used to demonstrate external validation at the biogeographic level. The a priori provinces as characterised by chlorophyll values cannot be statistically separated in either the data or the model. It is likely this is related to the arbitrary choice of province boundaries, which are not necessarily the same as those derivable from non-interpolated SeaWiFS data. The PCA comparison of modelled and observed chlorophyll demonstrated some objective skill in the model as it generally captures the dominant mode of the data, although severe mismatch was identified in certain regions by visual comparison (Indian and Southern Oceans). The model also overestimated seasonal variability compared to the data. The method shows promise for helping overcome problems with model verification due to undersampling of most ocean biogeochemical variables. http://hdl.handle.net/2122/3556 Title: Scenarios of earthquake-generated tsunamis in the Adriatic Sea <br/> <br/>Authors: Tiberti, M. M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Lorito, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Basili, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Kastelic, V.; University of Ljubljana, Department of Geology, Aškerčeva 12, 1000 Ljubljana, Slovenia; Piatanesi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Valensise, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia <br/> <br/>Abstract: We calculated the expected impact on the Italian coast of the Adriatic Sea of a large set of tsunamis resulting from potential earthquakes generated by major fault zones. Our approach merges updated knowledge on the regional tectonics and scenario-like calculations of expected tsunami impact. We selected six elongated potential source zones. For each of them we determined a Maximum Credible Earthquake and the associated Typical Fault, described by its size, geometry and kinematics. We then let the Typical Fault float along strike of its parent source zone and simulated all tsunamis it could trigger. Simulations are based on the solution of the nonlinear shallow water equations through a finite-difference technique. For each run we calculated the wave fields at specified simulation times and the Maximum Water Elevation field, then generated travel-time maps and maximum wave-height profiles along the target coastline. Maxima were also classified in a three-level code of expected tsunami threat. We found that the southern portion of Apulia facing Albania and the Gargano promontory are especially prone to the tsunami threat. We also found that some bathymetric features are crucial in determining the focalization-defocalization of tsunami energy. We suggest that our results be taken into account in the design of early-warning strategies.