Major shifts in multidecadal moisture variability in the Mid-Atlantic region during the last 240 years

Abstract

The paucity of high-resolution paleoclimate records limits our ability to extend instrumental data into a longer time-frame and to better understand multidecadal climate variations in the Mid-Atlantic region. Here we present an ∼2 year-resolution endogenic calcite d18O record for the last ∼240 years from a freeze core at White Lake in northern New Jersey. The d18O data, consistent with the paleosalinity reconstructions from Chesapeake Bay, suggest regional-scale multidecadal moisture variations, including dry conditions at 1780-C1840, wet conditions at 1840-C1920, and ∼20 year moisture oscillations after 1920. We attribute these moisture changes to shifts in the extent and location of the jet stream and resultant change in storm track trajectories, with eastward and seaward displacement of storm tracks corresponding to dry climate. The increase in moisture variability since 1920, shortly after the steady increase in global air temperature, suggests that change in mean climate state can induce large changes in moisture variability. Copyright © 2010 by the American Geophysical Union.