234
b)
12
6
O~~~~-----''-------------~~---T~~L-~~--------~¥---6
-12~-----.-----'-----.-----''-----r-----.-----.------r-----r-1885
1895
1905
1915
1925
1935
1945
1955
1965
1975
Figure 18: (a) The first eigenvector of annual cyclone frequencies. (b) Time variation
of the annual weightings of the first eigenvector (EI ) of annual cyclone frequencies, N
America and W Atlantic. From Hayden 1981.
lation in the Subtropical Gyre compared with ventilation timescales means
that the Panulirus data are representative of watermass conditions in the
gyre as a whole.
Thus, acting in response to the twin coupled cells of the NAO, each at
its long term extreme state, deep convection in both the Greenland Sea and
the [shallower] ventilation of the Sargasso were both at maximum intensity
during the 1960's, and have since largely shut down.
b)
12
6
O~~~~-----''-------------~~---T~~L-~~--------~¥---6
-12~-----.-----'-----.-----''-----r-----.-----.------r-----r-1885
1895
1905
1915
1925
1935
1945
1955
1965
1975
Figure 18: (a) The first eigenvector of annual cyclone frequencies. (b) Time variation
of the annual weightings of the first eigenvector (EI ) of annual cyclone frequencies, N
America and W Atlantic. From Hayden 1981.
lation in the Subtropical Gyre compared with ventilation timescales means
that the Panulirus data are representative of watermass conditions in the
gyre as a whole.
Thus, acting in response to the twin coupled cells of the NAO, each at
its long term extreme state, deep convection in both the Greenland Sea and
the [shallower] ventilation of the Sargasso were both at maximum intensity
during the 1960's, and have since largely shut down.