The User Interface consists of two main sections:
• Section1: a control panel on the left (blue box in figure 1) for the selection of the type of oil, forecasting system, time and type of spill.
• Section2: a map inthemiddle of the home page (grey box in figure1) where the outputs are shown.
In Basic mode only the GENERAL PARAMETERS need to be set:
• Title (blue box in Fig.2)– enter specific simulation name (any name without blank spaces and symbols);
• Notes (blue box in Fig.2)– insert notes
• Start spill position (blue box in Fig.2)– click on the map to choose initial spill location or insert latitude and longitude. The chosen initial location will be shown on the map as a green pin-marker.
TYPE OF OIL (purple box in Fig.2)
The type of the oil is used for modelling the chemical transformations the oil undergoes ("oil weathering"). It can be specified either by Name or API:
• Name – the drop-down menu on the right contains an alphabetical list of oil types.
• API - the drop-down menu on the right contains a list of oil types ordered by API. Select nearest API to the oil in question.
FORECASTING SYSTEM (red box in Fig.2)
WITOIL uses input data of sea currents, sea surface temperature, and surface wind.
In the current version of WITOIL, the oceanographic data are hourly forecast fields produced by the Mediterranean ocean Forecasting System (MFS) at 1/16° horizontal resolution.
Furthermore, atmospheric data are forecast and analyses of wind provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) at 1/4° horizontal and 6-h temporal resolution. In future versions of WITOIL, data from other forecasting systems will be available.
TIME (orange box in Fig.2)
• Spill date – choose a date on which the spill started. Dates for which the input oceanographic and atmospheric data are available, are highlighted.
• Simulation length [hours] – enter the simulation length as a number of hours from the start of release to the end of spill tracking. Warning! Departure date incremented by simulation length must be still within the highlighted range of dates in order for WITOIL to work;
• Output frequency [hours] – choose a time-step for display of output maps from a drop-down menu;
TYPE OF SPILL (blue box in Fig.2)
Oil spills can be modelled either as instantaneous sources or as continuous releases:
• Instantaneous spill requires Total volume [ton] of released oil;
• Continuous spill requires inserting Duration [hour] and Spill rate [ton/hour] of the oil spill.
In basic mode, values obtained from expert users are set as default in ADVANCED INFO.
Thus, once GENERAL PARAMETERS are set, a job can be submitted by clicking on the SUBMIT button (see red circle in Fig.2). A progress bar appears with an indication of elapsed time. Submitted jobs can be cancelled before completion by clicking the STOP SIMULATION button. Upon job completion, the surface oil concentration at the last time step of the simulation automatically appears. Individual simulation frames can be displayed by means of the animation player control at the top-right corner of the map (see Fig.3).
The time indicator has a total of 5 buttons with the following functionality:
• 1 central large triangle: play animation of the sequence ;
• 2 center-lateral small triangles: "Go forward/backward by one time step"
• 2 lateral smaller triangles with vertical bar: "Skip to last/first time step"
Advance use of WITOIL
For advanced use of WITOIL, knowledge of oil spill modelling is recommended in order to properly set up parameters and interpret results. Further information on the model used by WITOIL can be found on the MEDSLIK-II page (http://gnoo.bo.ingv.it/MEDSLIKII/).
ADVANCED INFO includes following parameters (see Fig.4):
• Stokes drift: Yes means accounting for wave-induced velocity (Stokes drift) calculated by empirical formulas.
• Wind correction [%]: If not zero, the direct influence of windage will be taken into consideration.
• Horizontal diffusivity [m2/s]: Parameter affecting oil horizontal dispersion.
• Evaporation rate [m/s]: Parameter affecting oil evaporation.
• Dispersion rate [1/s]: Parameter affecting oil dispersion due to breaking waves.
• Thick slick spreading rate [1/s]: Parameter affecting the viscous-gravity spreading of the oil slick.
• Oil parcel number [#]: Parameter for defining the number of Lagrangian particles by which the oil slick is represented.
VISUALIZATION SETTINGS includes :
• Simulation result visualization, which allows the separated or combined rendering the surface oil concentration and oil concentration at coast. A wind option shows wind speed at the oil center-of-mass and currents option presents local surface currents in the vicinity of the oil slick.
• Meteo-oceanographic data allows the simulation results to be displayed with the map of forecast fields on a larger scale. At present, only surface current fields can be displayed this way.
In the Computed Simulation section, it's possible to view the state of a job including the :
• Submission date
• Simulation date
• Duration [hours]
Click on the eye to recover a stored simulation.
Once the user submits a job, a progress bar is displayed in the Computed Simulations section (see fig.6)
A job that has been submitted can be cancelled by clicking on the recycle bin on the right.