Analysis of the Ice Model Simulation for the Gulf of Finland In 2002/2003 
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Ice conditions 
The ice season of 2002/03 started with rapid ice formation. In the early November 2002 ice 
cover begin to develop in the Bothnian Bay and in the Gulf of Finland. At the end of December 
the whole Gulf of Finland was covered by the ice, ice thickness was from 15 cm in west to 50 
cm in east (Pastukhov 2003). 
The maximum thickness of fast ice from 70 to 90 cm in the north of Bothnian Bay, 60 to 75 cm 
in the Sea of Bothnia, 50 to 65 cm in the western Gulf of Finland and 65 to 80 cm in the 
eastern Gulf of Finland. The maximum ice thickness in open sea was 40 to 60 cm in the Bay of 
Bothnia, 20 to 40 cm in the Sea of Bothnia, 5 to 20 cm in the northern Baltic Sea and 40 to 75 
cm in the Gulf of Finland. The ice season lasted over one month longer than on the long-term 
average in the Gulf of Finland and about two weeks longer in the Bothnian Bay (FIMR, 2003). 
In 2003 was ice very thick and deformated, navigation was difficult and restrictions valid 11T- 
149 days (Seina 2003) If the ice breaking was usually needed since January then 2003 year 
was different, icebreakers were needed already since December. And maximum extent of ice 
was achieved in Gulf of Finland on 5 of March with 232000 km 2 . 
Vessels needed already in January to navigate through the ice for the longest way in 40 years. 
Sailing distance reached up to 200 nautical miles, average distance is about 50 nautical miles. 
The season 2002/03 was classificated as an average season in Baltic sea but severe ice 
thickness in Golf of Finland. (Seina 2003). 
Results 
The total ice extent during the winter 2002/03 was already very large since at the beginning of 
January. On 16 th of January total ice concentration decreases quickly from 100% to 70 % 
mains due to ice deformation (Fig 3). The ice deformed at sharply growing rate this time. Time 
series of simulated mean total ice concentration is in good agreement with observed data. We 
see the deformed ice concentration increasing at the fig. 4 between longitude 23.7-25E and 
27.5-28E. We see in fig. 5, mean total ice thickness increase at the Estonian coast. Wind 
speed over 8 m/s blew to NE induce ice deformation at the south and east coast.