The results of the updated and quality-checked data base of field observations on chlorophyll a (Chl a) collected in the period 1970–2007 in the Northern Adriatic Sea are presented. From the last decade, SeaWiFS satellite information was... more
The results of the updated and quality-checked data base of field observations on chlorophyll a (Chl a) collected in the period 1970–2007 in the Northern Adriatic Sea are presented. From the last decade, SeaWiFS satellite information was also considered. Results demonstrate a global tendency towards Chl a reductionintheperiodof investigation, which is more marked in the eutrophic area under the influence of the Po River. In the rest of the basin, which presents meso- or oligotrophic characteristics, long-term changes are more difficult to detect. The long-term field dataset can be divided into two periods: the last decade characterized by the strong decrease observed in the whole northern Adriatic and the earlier
Three-dimensional models require a large amount of data for characterising the space and time evolution of the system and for testing the adequacy of the model. Remote sensing can greatly improve the results of these models because makes... more
Three-dimensional models require a large amount of data for characterising the space and time evolution of the system and for testing the adequacy of the model. Remote sensing can greatly improve the results of these models because makes available space-time series of data hardly obtainable in other ways. Indeed, traditional kind of measurement, while more accurate, cannot provide data sampled as often, and on as a fine mesh, as the ones obtainable by remote sensing technique. Experimental observations derived from remote sensing images, has been coupled with a 3D-water-quality model, to analyse the effects of eutrophication in the lagoon of Venice, namely to define the modality of the spatial expansion of macroalgae community. The model covers the central part of the lagoon of Venice, that includes the industrial area and the historic town of Venice. It combines transport and tropic processes, describing the seasonal dynamic of the main community of macroalgae (Ulva r.), phytoplank...
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We introduce a new version of the Earth System Regional Climate model RegCM‐ES and evaluate its performances for the first time over the Mediterranean region. The novel aspect of this coupled system is the possibility to simulate the... more
We introduce a new version of the Earth System Regional Climate model RegCM‐ES and evaluate its performances for the first time over the Mediterranean region. The novel aspect of this coupled system is the possibility to simulate the dynamics of the marine ecosystem through a biogeochemical model, BFM (Biogeochemical Flux Model), coupled online with the ocean circulation model MITgcm (MIT general circulation model). The validation of atmosphere and ocean components has shown that the model is able to capture interannual and intermonthly variabilities of the atmospheric heat fluxes and spatial patterns of land surface temperature, precipitation, evaporation, and sea surface temperature with a general improvement compared to previous versions. At the same time, we diagnosed some prominent deficiencies as a warm and dry bias associated in summer with the resolution of the atmospheric module and the tuning of the boundary layer and convective precipitation scheme. On the biogeochemical ...
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We describe a new, state‐of‐the‐art, Earth System Regional Climate Model (RegCM‐ES), which includes the coupling between the atmosphere, ocean, and land surface, as well as a hydrological and ocean biogeochemistry model, with the... more
We describe a new, state‐of‐the‐art, Earth System Regional Climate Model (RegCM‐ES), which includes the coupling between the atmosphere, ocean, and land surface, as well as a hydrological and ocean biogeochemistry model, with the capability of using a variety of physical parameterizations. The regional coupled model has been implemented and tested over some of the COordinated Regional climate Downscaling Experiment (CORDEX) domains and more regional settings featuring climatically important coupled phenomena. Regional coupled ocean‐atmosphere models can be especially useful tools to provide information on the mechanisms of air‐sea interactions and feedbacks occurring at fine spatial and temporal scales. RegCM‐ES shows a good representation of precipitation and SST fields over the domains tested, as well as realistic simulations of coupled air‐sea processes and interactions. The RegCM‐ES model, which can be easily implemented over any regional domain of interest, is open source, maki...
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The task technology is one of most promising to exploit node parallelism for next generation of HPC architectures, like those under development within the CORAL initiative in the US. In general, single FPU performance is not going to... more
The task technology is one of most promising to exploit node parallelism for next generation of HPC architectures, like those under development within the CORAL initiative in the US. In general, single FPU performance is not going to increase any longer in contrast to single node performance. As a consequence, nodes architecture will feature more and more FPUs (proportional to the peak power of the node itself) and determine the need for an efficient technology able to take advantage of intra-node parallelism, reducing synchronization among threads and improving data locality to meet the memory hierarchy. In this paper we present a case study of node parallelization using SHYFEM code, a software for coastal area studies. To the best of our knowledge, this is one of the first work that shows how to fully parallelize a software with OpenMP task technology. We present the comparison between tasks and threads OpenMP programming paradigms, showing the advantages of using the hierarchical and asynchronous programming paradigm made available by OpenMP tasks.
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In this study, we investigate the dynamics of the bottom layer of the southern Adriatic Sea (eastern Mediterranean basin) by merging experimental measurements and numerical simulations. We hypothesize that the recently observed continuous... more
In this study, we investigate the dynamics of the bottom layer of the southern Adriatic Sea (eastern Mediterranean basin) by merging experimental measurements and numerical simulations. We hypothesize that the recently observed continuous density decrease over time, which was basically related to a temperature increase, and the following sudden density rise, which was caused by the intrusion of very dense water masses (cold but relatively fresh), constitute one cycle of a general “saw‐tooth” pattern: the alternation of long‐lasting and almost linear density decreases (mixing phases) and sudden density increases (dense water intrusion phases). The model results, which provide a basin‐scale view of the process, corroborate this theory because they satisfactorily reproduced the observed oceanographic features. We describe the almost linear density decrease in terms of local mixing fostered by the advection of flow instabilities that originate from the large‐scale quasi‐permanent cyclon...
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The dynamics of the bottom layer of the southern Adriatic Sea are investigated merging experimental data and numerical simulations. The observed continuous temperature and salinity increase, interrupted by the sudden intrusion of very... more
The dynamics of the bottom layer of the southern Adriatic Sea are investigated merging experimental data and numerical simulations. The observed continuous temperature and salinity increase, interrupted by the sudden intrusion of very dense water masses, is hypothesized to be one cycle of a general "saw-tooth" pattern: alternation of long-lasting linear increase (mixing phase) and sudden decrease (dense water intrusion phase) of temperature and salinity. Model results corroborate this theory reproducing the observed oceanographic features and giving a basin-scale view of the investigated process.
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Some differences in the outputs of two coupled hydrodynamic-biogeochemical models in the Mediterranean Sea are found when both simulations are compared in the same period of time. Physical variables derived from the hydrodynamic model... more
Some differences in the outputs of two coupled hydrodynamic-biogeochemical models in the Mediterranean Sea are found when both simulations are compared in the same period of time. Physical variables derived from the hydrodynamic model Océan Parallélisé (OPA) are used in order to forced a biogeochemical-transport model (OPATM-BFM) developed at OGS with two different purposes: operational, in the frame of VECTOR Project, and climatological, in the frame of MERSEA Project. Although the hydrodynamic model and its atmospheric forcing (ECMWF analysis) are the same, they have different configurations -some examples are the vertical discretization, the vertical eddy diffusivity parameterization and the incorporation or not of data assimilation- for the operational and the climatological simulations. The first one has been provided by M. Pinardi and coauthors (INGV, Italy) while the second one is provided by K. Béranger (ENSTA, France). In this sense, it is expected that the discrepancies fo...
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Research Interests: Engineering, Physics, Chemistry, Biology, Marine Conservation, and 15 morePopulation Dynamics, Environmental Monitoring, Medicine, Multidisciplinary, Mediterranean Sea, Animals, Fishes, PLoS one, Marine Fish, Ecosystem, Time Factors, Fish Community, Conservation of Natural Resources, Species Specificity, and Marine ecosystem
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The effects of long-line mussel farming on microphytobenthos were investigated in a coastal area of the Gulf of Trieste. Sediment grain-size, organic matter content, microalgal abundance and community structure were analysed in September... more
The effects of long-line mussel farming on microphytobenthos were investigated in a coastal area of the Gulf of Trieste. Sediment grain-size, organic matter content, microalgal abundance and community structure were analysed in September 2008 and March 2009. Four areas were sampled: a twenty-year farm, a four-year farm, a disused farm and a reference site. Principal component analysis (PCA) highlighted a decreasing gradient of organic matter content from the twenty-year farm to the control. Mussel farming seemed to influence microphytobenthic abundance with higher densities in the oldest farm. Three genera were dominant; Navicula and Gyrosigma seemed to be stimulated by the organic load under the active farms while we infer that Nitzschia proliferation was limited by shade caused by mussel ropes. In the PCA, samplings of the disused farm were placed in-between the still active farms and the control, indicating the partial recovery occurred in this site.
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Research Interests: Environmental Science, Geology, Oceanography, Kinetics, Data Assimilation, and 15 moreCarbon Cycle, Phytoplankton, Phosphorus, Case Study, Nitrogen, Trophic Level, Water Temperature, Nutrient, Primary Production, Ecosystem, Marine Systems, Functional Group, Marine ecosystem, Chlorophyll a, and ecosystem model
Research Interests: Human Geography, Environmental Science, Oceanography, Multivariate Statistics, Water quality, and 12 moreStatistical Analysis, Multivariate Analysis, Seasonality, Regression Analysis, Spatial Distribution, Spatial Variability, Geographic distribution, Marine Systems, Water Quality, Residence Time, Tributary, and Chlorophyll a
Research Interests: Geology, Oceanography, Finite element method, Finite Elements, Finite Element, and 11 moreCalibration, Sediment transport, Finite Element Model, Two-Dimensional Hydrodynamic Model, Finite Temperature Field Theory, Marine Systems, Sediment Transport, Water Level, River Discharge, Temperature field, and Hydrodynamic Model
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An ensemble data assimilation scheme, Error Subspace Statistical Estimation (ESSE), is utilized to investigate the seasonal ecosystem dynamics of the Lagoon of Venice and provide guidance on the monitoring and management of the Lagoon,... more
An ensemble data assimilation scheme, Error Subspace Statistical Estimation (ESSE), is utilized to investigate the seasonal ecosystem dynamics of the Lagoon of Venice and provide guidance on the monitoring and management of the Lagoon, combining a rich data set with a physical‐biogeochemical numerical estuary‐coastal model. Novel stochastic ecosystem modeling components are developed to represent prior uncertainties in the Lagoon dynamics model, measurement model, and boundary forcing by rivers, open‐sea inlets, and industrial discharges. The formulation and parameters of these additive and multiplicative stochastic error models are optimized based on data‐model forecast misfits. The sensitivity to initial and boundary conditions is quantified and analyzed. Half‐decay characteristic times are estimated for key ecosystem variables, and their spatial and temporal variability are studied. General results of our uncertainty analyses are that boundary forcing and internal mixing have a s...
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Libralato, S., and Solidoro, C. 2010. Comparing methods for building trophic spectra of ecological data. – ICES Journal of Marine Science, 67: 426–434. The distribution of biomass, production, and catches over trophic levels (TLs) of the... more
Libralato, S., and Solidoro, C. 2010. Comparing methods for building trophic spectra of ecological data. – ICES Journal of Marine Science, 67: 426–434. The distribution of biomass, production, and catches over trophic levels (TLs) of the foodweb has been shown theoretically and empirically to provide powerful insights into ecosystem functioning and the effects of fishing. One approach for building trophic spectra of ecological data is based on smoothing original data and assuming zeroes when no values are available for a TL (smoothing-based method). An alternative method is proposed, based on the distribution of ecological data according to density functions (dispersion-based method), and a systematic review of the different alternatives is presented. Six different methods for building trophic spectra, i.e. the smoothing-based and five alternative forms for dispersion-based (using normal, lognormal, and Weibull distributions, also including shifted lognormal and Weibull with zero at...