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Scenario
The Scenario used to create a Virtual Ecosystem
The scenario describes the exogenous influences on the virtual ecosystem. The VEW contains global data sets, which are interpolated to provide the ambient conditions at the geographical location of the mesoscosm.
The world ocean
The scenario is global. It allows the mesocosm to drift anywhere in the world ocean.
Ocean circulation
The default ocean circulation is a global data set derived OCCAM (Southampton Oceanography Centre), but you can substitute others. The velocity fi eld has a resolution of one month at one degree of latitude and longitude and twenty levels. The user specifi es which levels will govern the advection of the mesocosm (typically the top 100m).
The track of a virtual mesocosm
The mesocosm drifts for ten years in the Mediterranean Sea from Catalonia to Egypt.
Ocean hydrography
The Workbench stores global hydrogaphy from the NOAA World Atlas. (You can add others.) This is used to create the initial conditions for the virtual ecosystem. The most important variables are nutrient concentrations. We have processed the NOAA climatology to fi ll gaps, in particular missing winter values. The VEW automatically interpolates the data to the starting geographical location and date.
Here we see the map of silicate concentration in the mixed layer.
Weather
The workbench contains the state of the weather every six hours at intervals of one degree of latitude and longitude. The data set extends from 1958 to 2002. It is derived from the Re-analysis carried out by the European Centre for Medium range Weather Forcasting (ERA45). The weather the following variables:
- cloud cover (for computing solar irradiance)
- surface flux of sensible heat
- surface flux of latent heat
- surface flux of long wave radiation
- surface wind velocity.
Climate
For some investigations it is convenient to use monthly-mean climate derived from ERA data. This is stored in the Workbench, and used to compute the ambient climate of the virtual mesocosm.
The climate data set also contains the atmospheric partial presure of carbon dioxide (ApCO2) from 1958 to 2002. Using the Events tool, you can extend this time series into the future following a scenario from the Inter- Governmental Panel for Climate Change.
