Photo: Hanneke Luijting

About AROME-Arctic

AROME-Arctic is a regional short-range high-resolution forecasting system for the European Arctic with 2.5 km grid spacing and 65 vertical levels (Müller et al. 2017). The model system is based on the HARMONIE-AROME configuration of the ALADIN-HIRLAM numerical weather prediction system (Bengtsson et al. 2017). The HARMONIE-AROME system is part of the code base of the IFS/ARPEGE system of ECMWF and Meteo-France, and it uses the same non-hydrostatic dynamical core as AROME-France described by Seity et al. (2010).

AROME-Arctic is very similar to the Nordic setup MetCoOp (Müller et al. 2017). Since June 2017, the operational AROME-Arctic is based on the cycle version 40h1.1. It issues deterministic forecasts 4 times a day with a lead time of 66 hours.

Data assimilation

AROME-Arctic utilises a three-dimensional variational data assimilation (described by Brousseau et al. 2011) with 3-hourly cycling to assimilate conventional observations, scatterometer ocean surface winds (Valkonen et al. 2017) and satellite radiances. Additionally, the operational system includes a so called “large scale mixing” where the large spatial scales are blended with the ECMWF high resolution model (HRES) forecasts to obtain the background field. Data assimilation of surface variables (2 m temperature, 2 m humidity and snow depth) in the AROME-Arctic is based on optimal interpolation.

Boundary conditions

The ECMWF HRES forecasts with 1-h interval are used as lateral boundary conditions. Sea ice concentration and  sea surface temperature are also obtained from the ECMWF. The surface temperature over sea-ice is taken once from ECMWF (cold-start), and is subsequently modelled by a 1D sea-ice model.


The Arctic forecast and research activities at MET Norway focus on the use and further development of the AROME-Arctic system. In addition to the core activities at MET Norway, AROME-Arctic is a part of a variety of research projects, for example, APPLICATE, CARRA, Nansen LEGACY, and NORDNWP PGD.


Bengtsson, L., U. Andrae, T. Aspelien, Y. Batrak, J. Calvo, W. de Rooy, E. Gleeson, B. Hansen-Sass, M. Homleid, M. Hortal, K. Ivarsson, G. Lenderink, S. Niemelä, K.P. Nielsen, J. Onvlee, L. Rontu, P. Samuelsson, D.S. Muñoz, A. Subias, S. Tijm, V. Toll, X. Yang, and M.Ø. Køltzow, 2017: The HARMONIE–AROME Model Configuration in the ALADIN–HIRLAM NWP System. Mon. Wea. Rev., 145, 1919–1935, https://doi.org/10.1175/MWR-D-16-0417.1

Brousseau, P., L. Berre, F. Bouttier, and G. Desroziers (2011), Background-error covariances for a convective-scale data-assimilation system: AROME-France 3D-Var, Q.J.R.Meteorol. Soc., 137, 409–422, doi: 10.1002/qj.750.

Müller, M., M. Homleid, K. Ivarsson, M.A. Køltzow, M. Lindskog, K.H. Midtbø, U. Andrae, T. Aspelien, L. Berggren, D. Bjørge, P. Dahlgren, J. Kristiansen, R. Randriamampianina, M. Ridal, and O. Vignes, 2017: AROME-MetCoOp: A Nordic Convective-Scale Operational Weather Prediction Model. Wea. Forecasting, 32, 609–627, https://doi.org/10.1175/WAF-D-16-0099.1 

Müller, M., Y. Batrak, J. Kristiansen, M.A. Køltzow, G. Noer, and A. Korosov, 2017: Characteristics of a convective-scale weather forecasting system for the European Arctic. Mon. Wea. Rev., accepted, https://doi.org/10.1175/MWR-D-17-0194.1 

Seity, Y., P. Brousseau, S. Malardel, G. Hello, P. Bénard, F. Bouttier, C. Lac, and V. Masson, 2011: The AROME-France Convective-Scale Operational Model. Mon. Wea. Rev., 139, 976–991, https://doi.org/10.1175/2010MWR3425.1

Valkonen, T., H. Schyberg and J. Figa-Saldaña, "Assimilating Advanced Scatterometer Winds in a High-Resolution Limited Area Model Over Northern Europe," in IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 10, no. 5, pp. 2394-2405, May 2017. doi: 10.1109/JSTARS.2016.2602889