Papers by Anna Maria Sempreviva
Wind Energy, 2003
Relatively few studies have been performed on the evaluation of offshore wind resources and these... more Relatively few studies have been performed on the evaluation of offshore wind resources and these have been conducted mostly in North Europe. In Mediterranean areas the lack of such studies is mainly linked to: 1) the difficulty of meteorological monitoring in deeper waters; 2) the complex orography, frequently extending down to the coasts; 3) the sea breeze wind regimes and 4) local winds such as Bora, Mistral or Sciroc. In the North Adriatic Sea, a shallow basin of the Mediterranean, the first reason is not applicable, but the others are sufficient to make evaluating wind speed methods challenging. In the present paper we estimate the wind climatology at a platform located 15 kilometres offshore of Venice based on seven-years of data and compare it with the wind climatology obtained using five different methods using the long-term data from four coastal meteorological stations: Venezia Tessera, Venezia San Nicolò, Ronchi and Rimini. We discuss the applicability of those methods and find that WAsP® model of Risø National Laboratory is still the best tool for wind climate estimates. The results of new methods are promising but still require some development.
Wind Energy, 2006
To obtain the offshore wind climatology over the whole Mediterranean region, European Centre for ... more To obtain the offshore wind climatology over the whole Mediterranean region, European Centre for Medium-range Weather Forecasts (ECMWF) 6-hourly wind data over a grid resolution of 0·5° × 0·5° for a period of 24 years have been retrieved. Data sets at 850 and 700 hPa pressure levels and 10 m above the surface were downloaded. For each grid point, mean wind speeds and Weibull probability density function parameters have been computed. As the wind field of ECMWF at 10 m is less accurate near the coast and in narrow basins, e.g. the Adriatic Sea, owing to the size of the mesh and land–sea mask smoothness, these statistics have been corrected, for each grid point, with the statistics produced using 2 year runs of a limited-area model with a grid size of 10 km. Results have been compared with experimental data from buoys, islands and ships in various regions of the basin. Maps of mean wind speeds and Weibull parameters are shown here for the whole Mediterranean Sea to illustrate these results. Copyright © 2005 John Wiley & Sons, Ltd.
Renewable energies such as wind and solar energy will play an important, even decisive role in or... more Renewable energies such as wind and solar energy will play an important, even decisive role in order to mitigate and adapt to the projected dramatic consequences to our society and environment due to climate change. Due to shrinking fossil resources, the transition to more and more renewable energy shares is unavoidable. But, as wind and solar energy are strongly dependent on highly variable weather processes, increased penetration rates will also lead to strong fluctuations in the electricity grid which need to be balanced. Therefore, it is today appropriate to scientifically address the requirements to provide the best possible specific weather information for forecasting the energy production of wind and solar power plants within the next minutes up to several days. Weather Intelligence in the sense of specific accurate forecasting of "energy weather" is a key component for this. Towards such aims, Weather Intelligence will first include developing dedicated post-processing algorithms coupled with weather prediction models and with past and/or online measurement data especially remote sensing observations. Second, it will contribute to investigate the difficult relationship between the highly intermittent weather dependent power production and concurrent capacities such as transport and distribution of this energy to the end users. Selecting, resp. developing surface-based and satellite remote sensing techniques well adapted to supply relevant information to the specific post-processing algorithms for solar and wind energy production short-term forecasts is a major task with big potential. It will lead to improved energy forecasts and help to increase the efficiency of the renewable energy productions while contributing to improve the management and presumably the design of the energy grids in the future. The second goal will raise new challenges as this will require first from the energy producers and distributors definitions of the requested input data and new technologies dedicated to the management of power plants and electricity grids and second from the meteorological measurement community to deliver suitable, short term high quality forecasts to fulfill these requests with emphasis on highly variable weather conditions and spatially distributed energy productions often located in complex terrain. This topic has been selected for a new COST Action ES1002 under the title "Short-Term High Resolution Wind and Solar Energy Production Forecasts" which will start in the second half of 2010 for a duration of 4 years.
During the austral summer 1998-'99 an experiment has been performed on the Nansen Ice Sheet in An... more During the austral summer 1998-'99 an experiment has been performed on the Nansen Ice Sheet in Antarctica to determine how the turbulence structure of the atmospheric boundary layer is modified by the interaction of westerly katabatic flows with a steeply sloping obstacle. It is 315 m high, a ridge elongated perpendicularly to the westerly wind trajectory. The behaviour of the standard deviation of velocity components, as well the change of the Monin-Obukhov stability parameter, along wind trajectories crossing the obstacle are studied to determine how the turbulence structure is perturbed by the orographic forcing and its space-time persistence in the downstream trajectories.
Comparative analysis of wind climate and breeze circulation at Ahtopol (Bulgarian Black sea coast... more Comparative analysis of wind climate and breeze circulation at Ahtopol (Bulgarian Black sea coast) and at Lamezia Terme (The wind energy potential in Mediterranean and Black Sea coastal zones is still not widely exploited, due to limited number of sites with measurements and in particular sites with intensive vertical wind profiles measurements. With the modern ground based remote sensing technology, new high time resolution information on wind in coastal areas is retrieved by the operation of sodars, wind Doppler lidars, ceilometers, etc. Here, we present a comparative study between two coastal sites: Ahtopol , Bulgaria, at the west coast of the Black Sea, and Lamezia Terme in Italy, located at the Tyrrhenian coast of the Calabrian Peninsula. The characteristics of the onset, duration, wind direction of sea breeze and the interaction of synoptic and local processes and the development of low level jets are studied. The comparison is performed considering the role of orography, coas...
Boundary-layer Meteorology, 2000
Results from an experimental investigation of themixing height over inner Danish waters carriedou... more Results from an experimental investigation of themixing height over inner Danish waters carriedout from September 1990 to October 1992, are discussed.
Boundary-layer Meteorology, 2000
Results from an experimental investigation of themixing height over inner Danish waters carriedou... more Results from an experimental investigation of themixing height over inner Danish waters carriedout from September 1990 to October 1992, are discussed.
Boundary-Layer Meteorology, 2008
Within the canopy sub-layer (CSL), variability in scalar sources and sinks are known to affect fl... more Within the canopy sub-layer (CSL), variability in scalar sources and sinks are known to affect flux-variance (FV) similarity relationships for water vapour (q) and carbon dioxide (C) concentrations, yet large-scale processes may continue to play a significant role. High frequency time series data for temperature (T ), q and C, collected within the CSL of an uneven-aged mixed coniferous forest in Lavarone, Italy, are used to investigate these processes within the context of FV similarity. This dataset suggests that MOST scaling describes the FV similarity function of T even though the observations are collected in the CSL, consistent with other studies. However, the measured FV similarity functions for q and C appear to have higher values than their temperature counterpart. Two hypotheses are proposed to explain the measured anomalous behaviour in the FV similarity functions for q and C when referenced to T . Respired CO 2 from the forest floor leads to large positive excursions in the C time series at the canopy top thereby contributing significantly to both C variance increase and C vertical flux decrease-both leading to an anomalous increase in the
Ciência e Natura, 2013
Neste trabalho investiga-se a camada limite atmosférica marinha diurna empregando a simulação dos... more Neste trabalho investiga-se a camada limite atmosférica marinha diurna empregando a simulação dos grandes turbilhões (LES) e observações atmosféricas do Ligurian Air-Sea Interaction Experiment (LASIE). O código LES utilizado neste trabalho foi modificado para descrever a evolução da camada limite sobe o mar. Os resultados da análise mostram que o modelo LES realístico é adequado para simular a camada limite atmosférica marinha.
The phenomenon of sand erosion is recently spreading in Mediterranean beaches in a worrisome way.... more The phenomenon of sand erosion is recently spreading in Mediterranean beaches in a worrisome way. Cellular Automata modelling such a phenomenon involves many difficulties for adopting a convenient time and space scale (minute and decimeter), that can permit temporally reasonable simulations. A very preliminary model RUSICA was developed in association with an experimental work in order to test hypotheses, to receive suggestion separately for some basic processes and to learn from past occurred cases. During this contamination phase, some experimental applications were succesfully projected in order to contrast sand erosion on the coast. This paper presents the current initial version of RUSICA for sand erosion/transport/deposition and describes the results obtained at Porto Cesareo coast in the Italian Apulia Region. Complete simulations by RUSICA will soon follow this preparatory work.
Neste trabalho investiga-se a camada limite atmosférica marinha diurna empregando a simulação dos... more Neste trabalho investiga-se a camada limite atmosférica marinha diurna empregando a simulação dos grandes turbilhões (LES) e observações atmosféricas do Ligurian Air-Sea Interaction Experiment (LASIE). O código LES utilizado neste trabalho foi modificado para descrever a evolução da camada limite sobe o mar. Os resultados da análise mostram que o modelo LES realístico é adequado para simular a camada limite atmosférica marinha.
The aim of this paper is to review the sources of wind and wave information, the methodologies to... more The aim of this paper is to review the sources of wind and wave information, the methodologies to assess offshore wind and wave energy resources, and the more relevant results at the European level as a first step to integration of the evaluation of both resources. In situ and remote sensed wind and wave data (using satellite based sensors) are done generally by distinct systems (except for SAR) but numerical atmospheric models and wind -wave models are closely related. Offshore wind resource studies using various types of data are reviewed especially in northern European seas and in the Mediterranean. The wave energy resource assessment at European and national levels is also reviewed and the various atlases are identified.
Results from an experimental investigation of the mixing height over inner Danish waters carried ... more Results from an experimental investigation of the mixing height over inner Danish waters carried out from September 1990 to October 1992, are discussed.
Wind Energy, 2006
To obtain the offshore wind climatology over the whole Mediterranean region, European Centre for ... more To obtain the offshore wind climatology over the whole Mediterranean region, European Centre for Medium-range Weather Forecasts (ECMWF) 6-hourly wind data over a grid resolution of 0·5°¥ 0·5°for a period of 24 years have been retrieved. Data sets at 850 and 700 hPa pressure levels and 10 m above the surface were downloaded. For each grid point, mean wind speeds and Weibull probability density function parameters have been computed. As the wind field of ECMWF at 10 m is less accurate near the coast and in narrow basins, e.g. the Adriatic Sea, owing to the size of the mesh and land-sea mask smoothness, these statistics have been corrected, for each grid point, with the statistics produced using 2 year runs of a limited-area model with a grid size of 10 km. Results have been compared with experimental data from buoys, islands and ships in various regions of the basin. Maps of mean wind speeds and Weibull parameters are shown here for the whole Mediterranean Sea to illustrate these results.
Boundary-Layer Meteorology, 1990
When air blows across a change in surface roughness, an internal boundary layer (IBL) develops wi... more When air blows across a change in surface roughness, an internal boundary layer (IBL) develops within which the wind adapts to the new surface. This process is well described for short fetches, < 1 km. However, few data exist for large fetches on how the IBL grows to become a new equilibrium boundary layer where again the drag laws can be used to estimate the surface wind.
Continuous measurements of PM 10 and PM 2.5 , aerosol size distribution (for Dp ranging from 280 ... more Continuous measurements of PM 10 and PM 2.5 , aerosol size distribution (for Dp ranging from 280 nm to 10 µm) and meteorological parameters are continuously performed since 1 st August 2013 at the CNR-ISAC Climatic Observatory of Lamezia Terme (40°3N, 18°1E, 50 m a.s.l.), in the framework of the PON/ERDF I-AMICA Project. In this work, we present and discuss a special event which occurred on 19 th November 2013, when a significant increase of PM 10 (up to 75 µg m -3 ) was observed. During the night between 16 th and 17 th November, an explosive eruption occurred at Mt. Etna. The analysis of HYSPLIT, i.e. three-dimensional back-trajectories, ending in Lamezia together with MOLOCH (MOdelloLOCale in H coordinates) meteorological simulations suggested that the volcanic plume from Mt. Etna affected Lamezia Terme on 19 th November. Moreover, for this case study, SEM-EDX analyses on PM 10 filters revealed the presence of large abundances of sulphur minerals, further corroborating the possibility that the large PM 10 value observed at the measurement sites could be tagged to the advection of volcanic ash.
Journal of Applied Meteorology, 2000
A numerical mesoscale model is used to study the wind field and the boundary layer structure of t... more A numerical mesoscale model is used to study the wind field and the boundary layer structure of the island of Sardinia during typical summer conditions. The numerical model is three-dimensional and employs a higherorder turbulence closure scheme. The model simulations were performed for summer conditions characterized by weak synoptic forcing from the northwest and clear skies. These conditions favor the development of thermal circulations, the most significant of which are the sea-breeze systems. The nighttime wind patterns generally are dominated by topography, which leads to the development of strong drainage flow. On the other hand, as revealed in the simulated wind field, at midday the wind has an onshore component at virtually every coastline. The well-organized sea-breeze systems interact to produce convergence zones. Another interesting feature is the development of a cyclonic eddy pattern during late-afternoon hours. The model results are compared with observations taken at a network of near-surface wind stations and rawinsonde profiles from the Cagliari airport. Available observations agreed relatively well with model predictions.
Meteorological Applications, 2013
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Papers by Anna Maria Sempreviva
grid integration. A suitable use of wind energy needs to setup methodologies able to reduce the uncertainty of the
wind resource.
The prediction system is usually based on meteorological models e.g. Limited Area Models (LAM). These models
predict the wind speed and direction in the target region and, by a turbine power curve, this output is converted in
wind power produced by a wind farm. Hence, the quality of the power forecast at different forecasting ranges is
strictly dependent on the quality of the prediction of the wind in the area of the wind power plant.
In Italy, wind farms are usually located in complex topographical regions, which mirror the complex orography of
the country. In this situation, wind prediction is more difficult than in flat terrain and a high spatial LAM resolution
is necessary to simulate the behavior of the wind.