10May2014_tromso2
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.

Development

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.

References

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