Ocean Cycles with Atlantic Hurricanes

Written by Joseph DÂ’Aleo


May 21, 2008
Ocean Cycles with Atlantic Hurricanes - an East Coast Threat in 2008?
By Joseph D’Aleo, CCM

In recent weeks we have posted stories about the Pacific Decadal Oscillation, the Atlantic Multidecadal Oscillation and ENSO and their effects on temperatures and Greenland and Arctic ice.

In this report, we look at how these same ocean cyclical oscillations influence the relative frequency of tropical storms, the number of strong storms and the most likely storm tracks and areas affected.

In recent months we have seen two prominent scientists (MIT’s Kerry Emanuel and NOAA’s Tom Knutson of the fluid dynamics lab at Princeton) who had earlier published papers linking global warming with increased Atlantic hurricane frequency and strength change their position on the basis of new data or models. We applaud these scientists for being willing to change their opinion when presented with conflicting data.

We believe these varying cycles of activity and tracks relate mainly to natural cyclical changes in the oceans. Dr. Bill Gray has shown how the frequency of Atlantic hurricanes and major hurricanes increase dramatically during the warm AMO phase (the case since 1995). We can see that surface pressure during hurricane season tends to be lower in the western Atlantic and Gulf when the Atlantic is in its warm mode (positive AMO).


In the cool PDO, there are more La Ninas and La Ninas favor more hurricanes due to less shear and storms threaten not only the Gulf as we find in El Ninos but are much more common along the East Coast from Florida to the Carolinas to New England.


If La Nina holds on and the AMO, which has weakened, rebounds (as it did in the La Nina summer of 1955), both the Gulf and the East Coast need to be wary this summer and fall more than in most years. See why here.


ICECAP, International Climate and Environmental Change Assessment Project, is the portal to all things climate for elected officials and staffers, journalists, scientists, educators and the public. It provides access to a new and growing global society of respected scientists and journalists that are not deniers that our climate is dynamic (the only constant in nature is change) and that man plays a role in climate change through urbanization, land use changes and the introduction of greenhouse gases and aerosols, but who also believe that natural cycles such as those in the sun and oceans are also important contributors to the global changes in our climate and weather. We worry the sole focus on greenhouse gases and the unwise reliance on imperfect climate models while ignoring real data may leave civilization unprepared for a sudden climate shift that history tells us will occur again, very possibly soon.


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