Hydroclimatic Variability in the Panama Bight Region During Termination 1 and the Holocene - Integrated Analysis of Interglacial Climate Dynamics (INTERDYNAMIC) - page 59

Hydroclimatic Variability in the Panama
Bight Region During Termination 1
and the Holocene

Matthias Prange, Silke Steph, Huadong Liu, Lloyd D. Keigwin
and Michael Schulz

Abstract A transect of sediment cores from high-sedimentation rate locations from
the Panama Bight (eastern tropical Paci

c) in combination with climate model
experiments provides an opportunity to improve our understanding of the role of
the tropical hydrologic cycle as a potential driver of global climate change during
the Holocene and Termination 1. The reconstruction of regional sea-surface salinity
patterns suggests the development of an anomalous precipitation dipole in the
tropical eastern Paci c during Heinrich Stadial 1 (H1) with reduced rainfall over

the western Panama Basin and off Costa Rica, and wetter conditions along the
Colombian coast. Freshwater hosing experiments with the climate model CCSM3,
mimicking the climatic reorganizations during H1, capture this precipitation dipole,
while showing no change in the Atlantic-to-Paci flux in response to a

slowdown of the Atlantic meridional overturning circulation (AMOC). We con-
clude that the cross-isthmus vapor

c water vapor

flux feedback on AMOC variations is negligible.

Keywords Termination 1 Heinrich stadial 1 Holocene Moisture transport

Atlantic meridional overturning circulation Panama bight Sea-surface salinity

Global climate modeling

1 Introduction

Today, a signi c is attributed to

the atmospheric transport of water vapor from tropical Atlantic/Caribbean sources
via the northeasterly trade winds that cross Central America (e.g., Benway and Mix

cant portion of rainfall in the eastern tropical Paci