Numerical Weather Prediction

DMI carries out research and development on short range numerical weather prediction (NWP) modelling for usage in operational weather forecasting, serving the needs in weather forecasting for the societies in Kingdom of Denmark, including Denmark, Faroe Islands and Greenland.  Research and application on NWP is also carried out in externally funded projects and for specialized products.

DMI issues a hourly updated 2-day short range probabilistic weather forecast for Denmark, Faroe Islands and an extended area in North and West Europe. The forecasts are based on gridded model products with 2.5 km resolution. In addition, DMI is in the process of developing a rapid update nowcasting system with high resolution. For Greenland, the forecasts are issued with 3h update, also with a grid resolution of 2.5 km. For the southern Greenland coastal regions around Tasiilaq and souther Greenland coast, with particularly challenging and frequent storm occurrence, DMI also issues a 6 hourly updated 2 day forecast with a spatial resolution of 750 m, one of the finest ones in the world.

Operational numerical weather prediction is a great challenge. The main NWP model system used in DMI is Harmonie, which is a non-hydrostatic, mesoscale forecast system jointly developed by the international NWP consortium, HIRLAM (HIgh Resolution Limited Area Model). HIRLAM is a consortium consists of 10 European weather services including DMI. HARMONIE is a model jointly developed by HIRLAM in collaboration with Meteo France and the ALADIN consortium, the latter with national weather services in 15 countries in Europe and North Africa.

For operational HARMONIE system, measurement data on meteorological variables from diverse observation platforms such as surface stations, aircraft measurement, radio sondes, ships, buoys, weather radar and satellites are used in a three-dimensional variational data assimilation. The results of which,  together with a corresponding surface analysis, form the initial state for the HARMONIE forecasts.

Areas covered by the operational HARMONIE-arome forecast setup at DMI. The domains in blue are those with 2.5 km grid resolution covering North Europe and Faroe Islands (NEA), Greenland and Iceland (IGB). The domains in red are those with 750 m grid resolution covering some coast areas in southeast and southern Greenland. NEA is run with probabilistic forecast with hourly update. IGB is run with 3-hourly update and the 750 m models with 6-hourly update. All runs are for 2 day forecast.

In order to assess model uncertainties, ensemble prediction systems covering both Denmark and Europe are used. 

A separate activity focuses on optimum use of weather radar observations from the DMI’s radar network.


Projects

CARRA (Copernicus Arctic Regional ReAnalysis)

Project aims: A 24-year reanalysis with the same regional model setup will be implemented and run on two complementary domains to cover the European sector of the Arctic. This will be done with the HARMONIE-AROME model running at 2.5 km resolution. The project is planned for four years duration and starts with a design and setup phase, then the reanalysis enters production in Month 20. The reanalysis dataset will be continuously updated to provide a complete 24 years time series before the end of the project. The work also includes a proof-of-concept Pan-Arctic reanalysis to be run for one year duration.

DMI's role: DMI leads WP1, the work package on system development. DMI participates in all most task within WP2, the work package on input data, and will lead the WP2 tasks 2.1, 2.2 and 2.3 on physiography, glacier input and albedo, and SST and sea ice, respectively. Additionally, DMI will be responsible for the reanalysis production (part of WP3) for one of two CARRA model domains. This domain covers Greenland, Iceland and a few of the adjacent islands in the high Arctic. Met.no will be responsible for the reanalysis production in the other domain that covers the Barents Sea, Svalbard and Northern Scandinavia. Finally, DMI will contribute to WP4 on user guidance and support, in which documentation and guidance on the available products from the service will be made.

Funding: The Copernicus Climate Change Services (C3S) programme, which is a programme initiated by the EU commission. 

Period: Sept. 2017 - June 2021. (extended to August 2021)

Collaborators: Met.NO (det norske meteorologiske institutt), DMI, SMHI, Meteo France, IMO (Veðurstofa Íslands), FMI.

Participants from DMIKristian Pagh Nielsen, Xiaohua Yang, Jacob L. Høyer, Rasmus Tage Tonboe, Ruth Mottram, Bjarne Amstrup, Kai Sattler, Mats Dahlbom, Pia Nielsen-Englyst, Emy Alerskans, Peter L. Langen

E-GVAP (EIG EUMEETNET GNSS Water Vapour Programme; Link: E-GVAP )

Project aims: The purpose of E-GVAP is to provide estimates of atmospheric properties based on data from ground-ground GNSS receivers (GPS is one example) in near real-time for usage in operational numerical weather prediction and general weather forecasting. The main property estimated is the zenith tropospherica delay, which contains information about atmospheric humidity. The project is based on a tight collaboration between meteorology and geodesy.

DMI's role: DMI is the coordinator of the programme.

Funding: The programme is funded by the participating national metoffices
The programme is in addition funded implicitly by the geodetic institutions
delivering zenith total delay data at no cost.

Period: April 2005 - December 2018, with third phase running 2013-17, and latest extension (jan.2019 - dec.2023 - E-GVAP 4)

Collaborators: 17 European national metoffices
17 data analysis centers determining ZTD from raw GNSS data (mainly geodetic institutions, but also a few European metoffices and NOAA). A large number of regional GNSS network operators providing raw GNSS data for the analysis centers.

Participants from DMI: Henrik Vedel