title: Tropical rainfall over the last two millennia: evidence for a low-latitude hydrologic seesaw.
abstract: The presence of a low- to mid-latitude interhemispheric hydrologic seesaw is apparent over orbital and glacial-interglacial timescales, but its existence over the most recent past remains unclear. Here we investigate, based on climate proxy reconstructions from both hemispheres, the inter-hemispherical phasing of the Intertropical Convergence Zone (ITCZ) and the low- to mid-latitude teleconnections in the Northern Hemisphere over the past 2000 years. A clear feature is a persistent southward shift of the ITCZ during the Little Ice Age until the beginning of the 19th Century. Strong covariation between our new composite ITCZ-stack and North Atlantic Oscillation (NAO) records reveals a tight coupling between these two synoptic weather and climate phenomena over decadal-to-centennial timescales. This relationship becomes most apparent when comparing two precisely dated, high-resolution paleorainfall records from Belize and Scotland, indicating that the low- to mid-latitude teleconnection was also active over annual-decadal timescales. It is likely a combination of external forcing, i.e., solar and volcanic, and internal feedbacks, that drives the synchronous ITCZ and NAO shifts via energy flux perturbations in the tropics.
authors.affiliation: Geological Institute, Swiss Federal Institute of Technology Zurich (ETHZ), Sonneggstrasse 5, CH-8092 Zurich, Switzerland.|Department of Earth Sciences, University of Durham, Durham, DH1 3LE, UK.
authors.forename: Franziska A
authors.initials: FA
authors.lastname: Lechleitner
authors.affiliation: Sediment- and Isotope Geology, Institute for Geology, Mineralogy &Geophysics, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
authors.forename: Sebastian F M
authors.initials: SF
authors.lastname: Breitenbach
authors.affiliation: Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Telegrafenberg A43, 14471 Potsdam, Germany.
authors.forename: Kira
authors.initials: K
authors.lastname: Rehfeld
authors.affiliation: Department of Earth Sciences, University of Durham, Durham, DH1 3LE, UK.
authors.forename: Harriet E
authors.initials: HE
authors.lastname: Ridley
authors.affiliation: Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico, 87131 USA.
authors.forename: Yemane
authors.initials: Y
authors.lastname: Asmerom
authors.affiliation: Department of Anthropology, University of New Mexico, Albuquerque, New Mexico, 87131 USA.
authors.forename: Keith M
authors.initials: KM
authors.lastname: Prufer
authors.affiliation: Potsdam Institute for Climate Impact Research, P.O. Box 60 12 03, 14412 Potsdam, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Marwan
authors.affiliation: Potsdam Institute for Climate Impact Research, P.O. Box 60 12 03, 14412 Potsdam, Germany.|Department of Physics, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany.
authors.forename: Bedartha
authors.initials: B
authors.lastname: Goswami
authors.affiliation: Department of Anthropology and Institutes for Energy and the Environment, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Kennett
authors.affiliation: Department of Anthropology, University of New Mexico, Albuquerque, New Mexico, 87131 USA.
authors.forename: Valorie V
authors.initials: VV
authors.lastname: Aquino
authors.affiliation: Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico, 87131 USA.
authors.forename: Victor
authors.initials: V
authors.lastname: Polyak
authors.affiliation: Geological Institute, Swiss Federal Institute of Technology Zurich (ETHZ), Sonneggstrasse 5, CH-8092 Zurich, Switzerland.|Department of Climate Geochemistry, Max Planck Institute for Chemistry, 55128 Mainz, Germany.
authors.forename: Gerald H
authors.initials: GH
authors.lastname: Haug
authors.affiliation: Geological Institute, Swiss Federal Institute of Technology Zurich (ETHZ), Sonneggstrasse 5, CH-8092 Zurich, Switzerland.
authors.forename: Timothy I
authors.initials: TI
authors.lastname: Eglinton
authors.affiliation: Department of Earth Sciences, University of Durham, Durham, DH1 3LE, UK.
authors.forename: James U L
authors.initials: JU
authors.lastname: Baldini