German Weather Bureau’s ICON forecasts available as open data
Jan Verkade and Matthijs den Toom - June 25, 2018
Germany's National Meteorological Service, the Deutscher Wetterdienst (DWD), is the producer of the ICOsahedral Non-hydrostatic (ICON) Numerical Weather Prediction model. Currently, ICON comes in two flavours: a global product (ICON-global) and a ‘nested’, regional product (ICON-EU). An ICON ensemble product is being developed.
ICON forecasts have been in place for a number of years and have been available as a paid service. However, a June 2017 amendment to the “DWD Act” allows the DWD to make available all of its observations and forecasts without charge. Its rationale is economic in nature. “We hope that the economy in Germany will find ways to heave this treasure trove of data,” said the DWD’s President. “What is needed now are innovative business ideas on how to use the DWD’s weather and climate information for new and economically rewarding products.”
The ICON forecasts are made available through the DWD’s open data portal (https://opendata.dwd.de/). A large number of parameters is available including those used most often in hydrological forecasting. The forecasts are available to a lead time up to 120 hours in one-hour time steps for the first 78 hours. After that, its temporal resolution decreases to three hours. The spatial resolution of the products varies: ICON-global has an effective mesh size of approx 13 kilometers globally, whereas ICON-EU is made available in a resolution of 0.0625 degrees in both longitudinal and latitudinal direction. Over Delft, which is more or less in the centre of the ICON-EU domain, this coincides with a resolution of approx 4 by 6 kilometers in longitudinal and latitudinal direction, respectively.
Both ICON-global and ICON-EU are made available through a set of grib2 files. These files are available approx 3.5 hours after the forecast initialization times, which are 00UTC, 06UTC, 12UTC and 18UTC. The ICON-EU files can be readily imported by a Delft-FEWS application; currently, the ICON-global files need to be remapped (from icosahedral grid to rectangular grid) prior to import.
Open ICON data is currently used in various Delft-FEWS applications including the Deltares global fluvial and coastal flood forecasting systems as well as the fluvial forecasting systems for the Bandon, Ilen and Blackwater basins in the Republic of Ireland.
If you are interested in importing the ICON products into your Delft-FEWS application then would gladly share the relevant configuration files. We also have available General Adapter modules that allow for downloading (and, for ICON-global, remapping) the data. Please contact Dr Jan Verkade (email@example.com) to obtain these files or to discuss access to a data feed of ICON-global, remapped to a 0.125° rectangular grid.
Below images give an impression of the ICON products as visualized in a Delft-FEWS client.