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What Ends an Interglacial? Feedbacks
Between Tropical Rainfall, Atlantic
Climate and Ice Sheets During the Last
Interglacial
Aline Govin, Benjamin Blazey, Matthias Prange and Andr
Paul
é
Abstract How long the present interglacial will last remains under debate. This
project aims to determine the climatic mechanisms and sequence of events termi-
nating an interglacial period. By comparing new paleoclimate reconstructions and
climate model experiments, we investigate the impact of South American rainfall
changes on tropical Atlantic sea-surface salinity and Atlantic thermohaline circu-
lation at the end of the Last Interglacial (LIG). Model and proxy data show grad-
ually intensifying South American monsoonal precipitation and enhanced Amazon
discharge through the LIG, in response to increasing austral summer insolation.
However, an increased meridional temperature gradient at the end of the LIG
caused a strengthening of the North Brazil Current retro
ected
eastward the Amazon freshwater plume. Such changes in South American river
discharge contributed to decrease tropical and North Atlantic surface salinities,
resulting in a shift in regions of North Atlantic deep water convection and small
reduction in deep water formation.
ection which de
Keywords Last interglacial
Last glacial inception
Tropical precipitation
Atlantic ocean
Sea-surface salinity
Thermohaline circulation
Ice sheet
Model-data comparison
1 Introduction
When and how the present interglacial will end remains an open question (Tzedakis
et al.
2012
). With a relatively well-known climate, the Last Interglacial (LIG,
129 thousand years (ka) before present (BP)
116 ka BP) provides a unique
framework to investigate the climatic mechanisms terminating an interglacial period.
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