Influence  of  the  Temperature  on  Ice  Conditions  in  the  Bay  of  Bothnia  (Baltic  Sea)

27

Evolution  of  the  Virpiniemi  ice
thickness

Frequential  distribution  of
temperature  (1957-2004)

1991-92

2002-03

□

Slush

Maximum
Q3

□

Snow

Median

□

Snow  ice"

Q2

□

Clear  ice"

—

Minimum

□

Not  frozen  water

Compared  year

Fig.  3.  Ice  thickness  compared  to  the  frequential  distribution  of  temperature
Sources  :  Station  de  Virpiniemi  /  llmatieteellinen  Keskuslaitos  -  Station  of  Oulu

Explications
Low  temperatures  and  small  ice  cover  are  responsible  of  the  ice  growth  of  the  Bay  of  Bothnia.
But  other  elements  explain  the  formation  and  the  evolution  of  the  ice  pack.  The  wind  for
example  can  induce  important  deformations  of  the  ice  cover.  Boats  which  take  channels  made
by  ice  breakers  can  have  an  influence  on  the  deformation  of  the  ice  pack  as  well.  So  it  seems
important  to  take  care  about  elements  which  can  deform  the  ice  cover  or  move  the  stations  of
measurement.  The  aquatic  fauna  can  slow  the  ice  growth.