poses; a combined surface circulation = sea temperature index produces no im= 
provement. Conceivably extension of the work to the period following 1945 
might do better since upper-air data can be used from then onward. 
When the time scale of correlation is increased to five years and more 
much better relations appears Only the secular trends are important in con= 
sidering these longer periods, The marked year-to-year changes drop out 2 
a 
"turbulenceo” Indeed, when fig. 2 is viewed as a whole, it gives the appear= 
ance of a typical turbulence record with underlying trend. 
Only a few indications of leng period correlaticns based on nen 
overlapping five-year means can be given here. As already noted, the sea ten 
perature at first declined, later rose over a largs part of the western Atlan= 
tic including the subtropics (fig. 2). For comparison, rige & shews the pres=- 
sure anomaly at 30°N, 65°W. Clearly, the pressure ross as the sea temperature 
decreased, then the reverse took placee At the same tims, the geostrephic 
vorticity in the Bermuda area at first became more 
eyslonisce These date furnish strong ciues nding of secular 
trends o 
Even the hurricane frequencies become fairly manageable on the five- 
year tims scale. Figs 9 correlates hurricanes frequencies and sea temperatures 
in the region of formation for non-overlapping five-year periodse Though not 
wholly satisfactory, a parallel trend is nevertheless evidents One may raise 
the question whether figs. 8 and 9 demonstrate a general principle, namely 
that ocean temperature and atmosphere are correlated only when time steps of 
about five years or more are considered, and that other factors dominate 
shorter period fluctuations. 
