Analysis of the Ice Model Simulation for the Gulf of Finland In 2002/2003 
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Analysis of the Ice Model Simulation for the Gulf of Finland in 
2002/2003 
Ove Pärn*, Jari Haapala+, 
* Systems Institute at Tallinn Technical University, Estonia, Email ove@sea.ee 
+ Finnish Institute of Marine Research, Finland, Email iari.haaDala@fimr.fi 
Abstract 
In this study we have analysed the multi-category sea-ice model (FIELMI) results in order to 
examine characteristics of deformation in Gulf of Finland. We investigated how the increase of 
deformed ice is related to wind speed and direction and how the ice conditions varies in space 
and time. 
Background 
The seasonal ice cover is of great importance to the countries surrounding the Baltic Sea, as 
year-round navigation is essential for the national economies in these countries. The Gulf of 
Finland is an important corridor for Russian, Finland and Estonian shipping. In winter vessels 
must navigate through the ice, in normal winter at last 150 nautical miles and maximum sailing 
distance to the ice-edge was 400 nautical mile in 1961-1990 (Seina 2003). 
The first ice forms on the Gulf of Finland at the beginning of December and breaks up in the 
end of April. The thickness of undeformed ice in the Gulf of Finland may reach 0.8 m in the fast 
ice but in the pack ice region the thickness of level ice seldom exceeds 0.5 m, and ice ridges 
are typically 5-10 m thick. 
During an average winter the whole northern Baltic Sea is ice covered. Even in a mild winter on 
the Gulf of Bothnia, Gulf of Finland and Gulf of Riga appears the ice. Sea ice is important 
because it regulates exchanges of heat and salinity in the sea. The sea ice affects both human 
activities and biological habitats. 
Deformation of sea ice is a key process determing the evolution of the sea-ice thickness 
distribution. Apparent results of the deformation are leads and ridges. Recent observations of 
the thickness by Flans (2004) have reveled that the mean ice thickness over several km 2 !! 
could be 2-3 meters in the Gulf of Finland. In this study we have analysed the multi-category 
sea-ice model (FIELMI) results in order to examine characteristics of deformation in the Gulf of 
Finland, and have investigated how the increase of deformed ice is related to wind speed and 
direction and how the ice conditions varies in space and time. 
Model Description 
The FIELMI model is a multicategory sea-ice model developed originally for the climate 
research (Flaapala et al., 2005). The model physics and numerics are same both in operational 
and climate simulations. The only differences are in the horizontal resolution and atmospheric