Sea surface temperature the passing of a hurricane primarily as the result of mixed layer deepening and surface heat losses. In the wake of several day long Saharan dust outbreaks across the adjacent northern Atlantic Ocean, sea surface temperatures are reduced 0.2 C to 0.4 C (0.3 to 0.7 F). Other sources of short-term SST fluctuation include extratropical cyclones, rapid influxes of glacial fresh water and concentrated phytoplankton blooms due to seasonal cycles or agricultural run-off. The Atlantic Multidecadal Oscillation (AMO) is important for how external forcings are linked with North Atlantic SSTs. El Niño is defined by prolonged differences in Pacific Ocean
Climate change in the United States fundamental problem exists in that records for those such events are of worse quality with poorer details than temperature and rainfall records. A comprehensive article in "Geophysical Research Letters" in 2006 found "no significant change in global net tropical cyclone activity" during past decades, a period when considerable warming of ocean water temperatures occurred. Significant regional trends exist such as a general rise of activity in the North Atlantic area besides the U.S. eastern coast. Looking at the lack of certainty as to the causes of the 1995 to present increase in Atlantic extreme storm activity, a 2007 article in