Investigation of mid-Holocene Climatic Teleconnections between Central America and Subtropical North America

Authors: Philip Van Beynen*, University of South Florida, Anna Pollock, University of South Florida, Kristine DeLong, Louisiana State University, Victor Polyak, University of New Mexico, Yemane Asmerom, University of New Mexico
Topics: Paleoenvironmental Change, Global Change, Geomorphology
Keywords: Paleoenvironmental Change, Isotopes, Speleothem, mid-Holocene, Florida, Belize
Session Type: Poster
Day: 4/5/2019
Start / End Time: 3:05 PM / 4:45 PM
Room: Lincoln 2, Marriott, Exhibition Level
Presentation File: No File Uploaded

The mid-Holocene provides an opportunity to investigate a warmer climate without the influence of the ephemeral North American Ice sheets. Higher levels of Northern Hemisphere insolation during the mid-Holocene should impact the regional influences of atmospheric-oceanic climate modes such as the Intertropical Convergence Zone (ITCZ), the Hadley Cell (HC) and the North Atlantic Subtropical High (NASH). To understand how these climate modes compared to today, we investigated mid-Holocene precipitation levels, from annually-resolved speleothem δ18O records. To determine the change in precipitation, we compared the mid-Holocene δ18O records to those of modern speleothem δ18O records from the tropics, represented by Belize and the subtropics, represented by Florida. In comparison to modern precipitations levels, mid-Holocene Belize experienced increased precipitation and Florida became more arid. Using the interpretations of other paleoprecipitation records and the modern influences of these climate modes on regional precipitation, we propose that the northward migration of the rising limb of the HC, and consequently the ITCZ, enhanced summer precipitation in Belize. This migration of the HC would force the NASH to the northwest thereby reducing convection over the Gulf of Mexico leading to less summer precipitation in Florida.

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