Derek Asadoorian

The Influence of the Southern and North Atlantic Oscillations on New England Climate

ASADOORIAN, Derek, Geology Dept., Bates College., 13 Bates College, Lewiston, Maine 04240, dasadoor@bates.edu.

We know from paleoclimate records that historical changes in We know from paleoclimate records that historical changes in Earth’s climate have not been gradual or consistent. The suspicion that humans have enough influence to provoke global climatic changes has caused environmental concerns to be launched to the forefront of science and public policy. Learning more about Earth’s climate will allow us to know more about how we are influencing climate, the magnitude of this influence, and consequently, what we can do to promote Earth’s welfare.

In the 1920s, Sir Gilbert Walker discovered and studied two systems that are of particular interest to climatologists today. They are called the Southern and North Atlantic Oscillations. Both are complex oceanic^?atmospheric coupled systems that have profound and often adverse global climate impacts. The dynamics of each oscillation consist of a two-tiered pressure system, whereby standard high and low pressure centers serve as “control dials.” In other words, changes in pressure differentials between the two centers cause different phases of each oscillation. By gaining a better understanding of what triggers the changes in phases and the specific effects of the changes, we may be able to construct a more reliable public policy concerning the contribution that humans make to these climatic events.

My research examines what kind of effects each system has on New England. The Southern Oscillation occurs in the South Pacific, and is a major controller of the jet stream that affects the United States. Thus, it is apparent that the Southern Oscillation has the potential to have a major influence on the weather that eventually comes to New England from the west. The North Atlantic Oscillation controls the interaction of the waters off the coast of New England with the atmosphere, and thus it has the potential to alter or control the weather that occurs in New England. Both systems have been shown to have certain effects on the Northeast region of the United States, but the degree and nature of those effects are still unclear.

The analysis includes approximately 100 years of temperature and precipitation data from 15 stations across New England. These statistics have been correlated with index values (normalized pressure differences) of each oscillation in order to provide answers as to the magnitude and effect each system has on the region. A multiple regression has also been performed in order to observe what kind of effect the two systems have on New England in tandem. Preliminary results show that neither system has a particularly strong influence on New England in contrast to what other studies have reported. These results tend to reflect the high magnitude of climate complexity in New England and possibly other regions of the world.