The accuracy of the forecasts improves considerably when combining the forecasts with online real-time measurements of water levels, currents and waves. This can be done in several ways:
- Measurements are assimilated into the models when they run in hindcast providing the starting conditions for the forecast simulations
- Measurements are used after forecasts has finished to correct the forecast at the locations where the measurements are made
- Measurements and forecasts are shown in the same graph which provides a visual impression of the accuracy of the measurements
The measurements can be provided in several ways:
- From DHI's Data Handling Centre, where measurements collected for customers by DHI are stored in a data base. DHI has a large range of instruments, which can be used as a part of a monitoring programme including communication, quality checking, storage and visualisation.
- From the customer (via an ftp site), which already have instruments deployed and are collecting measurements into a data base
- From a third party (via an ftp site) holding the data in a data base