BS 5 Visibility depth

Visibility depth or secchi depth is measured..

 


A) Visibility depth in Gulf of Finland (metres)

Year
         
     
1905
8.0
  1931
7.3
  1957
6.2
  1983
6.0
1906
8.0
  1932
7.2
  1958
6.2
  1984
6.0
1907
7.9
  1933
7.2
  1959
6.1
  1985
5.9
1908
7.9
  1934
7.2
  1960
6.1
  1986
5.8
1909
7.9
  1935
7.1
  1961
6.1
  1987
5.8
1910
7.9
  1936
7.1
  1962
6.1
  1988
5.7
1911
7.8
  1937
7.0
  1963
6.1
  1989
5.7
1912
7.8
  1938
7.0
  1964
6.1
  1990
5.6
1913
7.8
  1939
6.9
  1965
6.1
  1991
5.5
1914
7.8
  1940
6.9
  1966
6.1
  1992
5.4
1915
7.7
  1941
6.9
  1967
6.1
  1993
5.3
1916
7.7
  1942
6.8
  1968
6.1
  1994
5.2
1917
7.7
  1943
6.8
  1969
6.1
  1995
5.2
1918
7.7
  1944
6.7
  1970
6.1
  1996
5.0
1919
7.6
  1945
6.7
  1971
6.1
  1997
4.9
1920
7.6
  1946
6.6
  1972
6.2
  1998
4.8
1921
7.6
  1947
6.6
  1973
6.2
  1999
4.7
1922
7.6
  1948
6.5
  1974
6.2
  2000
4.6
1923
7.5
  1949
6.5
  1975
6.2
  2001
4.5
1924
7.5
  1950
6.4
  1976
6.2
  2002
4.5
1925
7.5
  1951
6.4
  1977
6.2
  2003
4.4
1926
7.4
  1952
6.4
  1978
6.2
  2004
4.4
1927
7.4
  1953
6.3
  1979
6.1
  2005
4.3
1928
7.4
  1954
6.3
  1980
6.1
  2006
4.3
1929
7.4
  1955
6.3
  1981
6.1
  2007
4.3
1930
7.3
  1956
6.2
  1982
6.0
  2008
4.4


B) Visibility depth in Bothnian Sea (metres)

Year
         
     
1905
8.9
  1931
9.5
  1957
7.5
  1983
6.6
1906
8.9
  1932
9.5
  1958
7.4
  1984
6.6
1907
9.0
  1933
9.4
  1959
7.3
  1985
6.5
1908
9.0
  1934
9.4
  1960
7.2
  1986
6.5
1909
9.1
  1935
9.3
  1961
7.2
  1987
6.4
1910
9.1
  1936
9.3
  1962
7.1
  1988
6.4
1911
9.2
  1937
9.2
  1963
7.0
  1989
6.3
1912
9.2
  1938
9.1
  1964
7.0
  1990
6.3
1913
9.3
  1939
9.1
  1965
6.9
  1991
6.2
1914
9.3
  1940
9.0
  1966
6.9
  1992
6.1
1915
9.3
  1941
8.9
  1967
6.9
  1993
6.1
1916
9.4
  1942
8.8
  1968
6.8
  1994
6.0
1917
9.4
  1943
8.7
  1969
6.8
  1995
6.0
1918
9.4
  1944
8.6
  1970
6.8
  1996
5.9
1919
9.5
  1945
8.6
  1971
6.8
  1997
5.9
1920
9.5
  1946
8.5
  1972
6.8
  1998
5.8
1921
9.5
  1947
8.4
  1973
6.8
  1999
5.7
1922
9.5
  1948
8.3
  1974
6.8
  2000
5.7
1923
9.6
  1949
8.2
  1975
6.8
  2001
5.6
1924
9.6
  1950
8.1
  1976
6.8
  2002
5.6
1925
9.6
  1951
8.0
  1977
6.8
  2003
5.5
1926
9.6
  1952
7.9
  1978
6.8
  2004
5.5
1927
9.6
  1953
7.8
  1979
6.7
  2005
5.4
1928
9.6
  1954
7.7
  1980
6.7
  2006
5.3
1929
9.6
  1955
7.6
  1981
6.7
  2007
5.3
1930
9.5
  1956
7.6
  1982
6.6
  2008
5.2
  

C) Visibility depth in Bay of Bothnia (metres)

Year
         
     
1905
9.3
  1931
7.9
  1957
6.4
  1983
6.0
1906
9.2
  1932
7.9
  1958
6.3
  1984
6.0
1907
9.2
  1933
7.8
  1959
6.3
  1985
6.0
1908
9.1
  1934
7.8
  1960
6.2
  1986
5.9
1909
9.1
  1935
7.7
  1961
6.2
  1987
5.9
1910
9.0
  1936
7.7
  1962
6.2
  1988
5.8
1911
9.0
  1937
7.6
  1963
6.1
  1989
5.8
1912
8.9
  1938
7.5
  1964
6.1
  1990
5.7
1913
8.9
  1939
7.5
  1965
6.1
  1991
5.7
1914
8.8
  1940
7.4
  1966
6.0
  1992
5.6
1915
8.8
  1941
7.3
  1967
6.0
  1993
5.5
1916
8.7
  1942
7.3
  1968
6.0
  1994
5.5
1917
8.7
  1943
7.2
  1969
6.0
  1995
5.4
1918
8.6
  1944
7.1
  1970
6.0
  1996
5.3
1919
8.6
  1945
7.1
  1971
6.0
  1997
5.2
1920
8.5
  1946
7.0
  1972
6.0
  1998
5.1
1921
8.5
  1947
6.9
  1973
6.0
  1999
5.1
1922
8.4
  1948
6.9
  1974
6.0
  2000
5.0
1923
8.4
  1949
6.8
  1975
6.1
  2001
4.9
1924
8.3
  1950
6.8
  1976
6.1
  2002
4.8
1925
8.3
  1951
6.7
  1977
6.1
  2003
4.7
1926
8.2
  1952
6.6
  1978
6.1
  2004
4.6
1927
8.2
  1953
6.6
  1979
6.1
  2005
4.5
1928
8.1
  1954
6.5
  1980
6.1
  2006
4.3
1929
8.1
  1955
6.5
  1981
6.1
  2007
4.2
1930
8.0
  1956
6.4
  1982
6.0
  2008
4.1

Download data on a spreadsheet from here