MARIA - Malta Atmospheric and Wave Forecasting System
Project managed by: Dr. Aldo. Drago - Director, IOI-MOC, University of Malta
Structural Funds Programme for Malta 2004-2006; Project part-financed by the European Union Community Initiative Interreg III Medocc Programme.

Wave/Wind Climatologies for the Central Mediterranean area

The Wave and Wind climatologies prepared within the WERMED Project tasks 2.1 and 2.2 are based on the wind/wave hindcast HIPOCAS database consisting of a 44-year (1958 2001) dataset of wind and wave hourly values at a horizontal resolution of 0.125 deg. on the domain covering the area of interest over the Central Mediterranean area (35N - 39N and 10.25E - 16E, refer to Fig.1) . This homogeneous, long-term and high-resolution wind/wave hindcast database was developed within the EU R&D project HIPOCAS (Hindcast of Dynamic Processes of the Ocean and Coastal Areas of Europe). A state-of-the-art WAM wave model (WAMDI, 1988) was run for the period 1958-2001 over the Mediterranean.
Choose Level:
Level 1- Display charts of the selected parameters and statistical diagnostics on three temporal resolutions.
Level 2 - Display statistics and plots at a numberof pre-selected areas.
Level 3 -View and download data at user defined points, areas or transects for chosen periods.

The wave model was driven by hourly wind data generated by the regional atmospheric model REMO at the 0.5 deg horizontal resolution (Jacob and Podzun, 1997). The spatial and temporal resolution of the wind data used for wave model forcing was sufficient to resolve the critical coastal areas. The WAM model was run over the Mediterranean with the grid resolution of 0.50 deg and with two grids used in a 2-way nesting mode: one over the Eastern Mediterranean with 0.25 deg resolution and another over the Central Mediterranean with 0.125 deg resolution.

The comprehensive and consistent data set of hourly values of wave and wind parameters produced by the model is used for an analysis of spatial and temporal variability in the region of interest. The main advantage of the hindcasts is their high spatial and temporal resolution, that makes them the most suitable source for the climatology study in this area. The parameters used in analysis are: significant wave height (Hs), mean wave direction, peak period (Tp) of total sea (includes the both wind wave and swell components), wind speed (Ws) and wind direction.

Fig. 1 Domain covered by the climateology at 1/8 degrees resolution

The methodology consisted in preparing monthly time series of hourly values of wind and wave parameters at each grid point in the area of interest; statistical analysis of these monthly time-series is done by calculating mean values, standard deviation and minima/maxima, as well as the 99th, 90th, 75th, 50th and 25th percentiles for wind speed, significant wave height and wave period. Seasonal variability was more closely examined by studying the set of monthly extremes. The frequency (% occurrence) distribution of wind direction is calculated at a selected representative subset of points in order to identify the dominant wind conditions in the area of study.

The full climatology is compiled in the form of 2D plots, and summary tables and charts. The results are prepared at several levels:

  1. monthly and seasonal climatology maps of different parameters including mean wind speed and direction, mean max/min wind , extreme min/max wind , percentiles and standard deviation for mean wind speed, mean wave height and direction, mean max/min wave, extreme min/max wave, average mean/peak wave peroid, standard deviation for peak/mean;
  2. wind roses and wind frequency tables at selected points, including the approaches to the Maltese Islands;
  3. statistical information averaged over ten pre-defined zones.

The climatology can be accessed through this web interface which allows viewing at three levels:

Level 1- Displaying charts of the selected parameters and statistical diagnostics on three temporal resolutions;

Monthly January - December
Seasonal

Winter = Dec - Feb;Spring = Mar - May; Summer = Jun - Aug Autumn = Sep - Nov

Annual Averaging fields over the full year.
Level 2 - Allowing the user to select one of a number of pre-selected areas and displaying a set of statistics and a series of plots showing the monthly wave statistics for the selected area.
Level 3 - Allowing the user to choose a point, a customised area or transect from the map and request the viewing or downloading of data with full flexibility.

 

 

 

 

 



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