Interannual variation of persistent organic pollutants over the Great Lakes induced by tropical Pacific sea surface temperature anomalies

Abstract

The linkage between decadal monitored air concentrations of persistent organic pollutants (POPs) around the Great Lakes from 1992 to 2002 and the sea surface temperature anomalies (SSTA) in the tropical Pacific was studied on a year‐to‐year basis. It is shown that interannual fluctuation of air concentrations of α‐hexachlorocyclohexane (α‐HCH), hexachlorobenzene (HCB), and polychlorinated biphenyls (PCBs) measured in the Great Lakes basin in spring and summer are highly correlated with the tropical Pacific SSTA. Spatial correlation patterns between the air concentrations of POPs over the Great Lakes and SSTA exhibit a feature of the characteristic SST signature associated with the occurrence of an El Niño event and SSTA forcing in atmospheric circulation teleconnections. The relations between air concentration of these POPs and the tropical Pacific SSTA are consistent with the response of midlatitude atmospheric circulation to the Pacific SSTA, showing that air concentration of the POPs in spring and summer seasons is related to tropical Pacific SSTA in preceding winter and spring months. The up to 6 month lag response of the POP air concentration to the SSTA provides a basis for forecasting the temporal trend of POPs in the atmosphere over the Great Lakes basin. The connection of the SSTA and the changes in the POP air concentration with the atmospheric circulation suggests that the atmospheric circulation associated with the tropical Pacific sea surface temperature (SST) forcing plays a major role in the reemission of POPs from sources and long‐range transport of POPs in the atmosphere.