Impact of the Atlantic Warm Pool on precipitation and temperature in Florida during North Atlantic cold spells

Abstract

Recurrent phases of increased pine at Lake Tulane, Florida have previously been related to strong stadials terminated by so-called Heinrich events. The climatic significance of these pine phases has been interpreted in different ways. Using a pollen–climate inference model, we quantified the climate changes and consistently found that mean summer precipitation (PJJA) increased (0.5–0.9 mm/day) and mean November temperature increased (2.0–3.0 C) during pine phases coeval with Heinrich events and the Younger Dryas. Marine sea surface temperature records indicate that potential sources for these moisture and heat anomalies are in the Gulf of Mexico and the western tropical Atlantic. We explain this low latitude warming by an increased Loop Current facilitated by persistence of the Atlantic Warm Pool during summer. This hypothesis is supported by a climate model sensitivity analysis. A positive heat anomaly in the Gulf of Mexico and equatorial Atlantic best approximates the polleninferred climate reconstructions from Lake Tulane during the (stadials around) Heinrich events and the Younger Dryas.Recurrent phases of increased pine at Lake Tulane, Florida have previously been related to strong stadials terminated by so-called Heinrich events. The climatic significance of these pine phases has been interpreted in different ways. Using a pollen–climate inference model, we quantified the climate changes and consistently found that mean summer precipitation (PJJA) increased (0.5–0.9 mm/day) and mean November temperature increased (2.0–3.0 C) during pine phases coeval with Heinrich events and the Younger Dryas. Marine sea surface temperature records indicate that potential sources for these moisture and heat anomalies are in the Gulf of Mexico and the western tropical Atlantic. We explain this low latitude warming by an increased Loop Current facilitated by persistence of the Atlantic Warm Pool during summer. This hypothesis is supported by a climate model sensitivity analysis. A positive heat anomaly in the Gulf of Mexico and equatorial Atlantic best approximates the polleninferred climate reconstructions from Lake Tulane during the (stadials around) Heinrich events and the Younger Dryas.