Journal cover Journal topic
Geoscientific Model Development An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/gmd-2018-22
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Development and technical paper
20 Mar 2018
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Geoscientific Model Development (GMD).
Implementation of a simple thermodynamic sea ice scheme, SICE version 1.0-38h1, within the ALADIN-HIRLAM numerical weather prediction system version 38h1
Yurii Batrak1, Ekaterina Kourzeneva2, and Mariken Homleid1 1Development Centre for Weather Forecasting, Norwegian Meteorological Institute, Oslo, Norway
2Finnish Meteorological Institute, Helsinki, Finland
Abstract. Sea ice is an important factor affecting weather regimes, especially in polar regions. A lack of its representation in numerical weather prediction (NWP) systems leads to large errors. For example, in the HARMONIE-AROME model configuration of the ALADIN-HIRLAM NWP system, the mean absolute error in 2 metre temperature reaches 1.5 °C after 15 forecast hours for Svalbard. A possible reason for that is that the sea ice properties are not reproduced correctly (there is no prognostic sea ice temperature in the model). Here, we develop a new SImple sea iCE scheme (SICE) and implement it into the ALADIN-HIRLAM NWP system in order to improve the quality of its forecasts in areas influenced by sea ice. General evaluation of the new parameterization is performed within HARMONIE-AROME by experiments covering the Svalbard and Gulf of Bothnia areas for a selected period in March–April 2013. It is found that using the SICE scheme improves the forecast, decreasing the value of the 2 metre temperature mean absolute error on average by 0.5 °C in areas that are influenced by sea ice. The new scheme is sensitive to the representation of the form drag: it may increase the 10 metre wind speed bias on average by 0.4 m s−1 when the form drag is not taken into account. Also, the modelling results are compared with the sea ice surface temperature observations from MODIS. The warm bias (of approximately 5 °C) of the new scheme is indicated for the areas of thick ice in the Arctic. Impacts of the SICE scheme on the modelling results and possibilities for future improvement of sea ice representation in the ALADIN-HIRLAM NWP system are discussed.
Citation: Batrak, Y., Kourzeneva, E., and Homleid, M.: Implementation of a simple thermodynamic sea ice scheme, SICE version 1.0-38h1, within the ALADIN-HIRLAM numerical weather prediction system version 38h1, Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2018-22, in review, 2018.
Yurii Batrak et al.
Yurii Batrak et al.
Yurii Batrak et al.

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