Control of Seasonality and Interannual to Centennial Climate Variability in the Caribbean During the Holocene—Combining Coral Records, Stalagmite Records and Climate Models - Integrated Analysis of Interglacial Climate Dynamics (INTERDYNAMIC) - page 66

Keywords Tropical Atlantic Caribbean Sea Holocene Paleoclimate

Seasonality Interannual to centennial variability Corals Speleothems Climate

models

1 Introduction

Instrumental climate observations during the last 100 years indicate that interactions
of the tropical Paci c and Atlantic Oceans play a crucial role in controlling inter-

annual to multidecadal climate variability throughout the Caribbean region. Ocean-
atmosphere interactions on these timescales play a critical role for regional climate
extremes such as droughts,

floods and hurricanes. A better understanding of the
natural range of variability on these timescales is important for projections of future
climate change in this key region of the tropical Atlantic Ocean. However,
Caribbean proxy reconstructions that resolve climate variability on these timescales
are sparse. We reconstructed and studied the natural range of seasonality and
interannual to centennial climate variability in the Caribbean during the Holocene,
by using marine and terrestrial climate archives. The major aim was to reconstruct
variability of the surface ocean and the atmosphere, and to explain the reconstructed
changes with climate model simulations. Shallow-water corals from fossil reef
deposits of the southern Caribbean were used to reconstruct temperature and
hydrologic balance at the sea surface. Speleothems from caves in the northern
Caribbean were used to reconstruct rainfall intensity. Model simulations were used
to place the proxy-based results in a large-scale climatic context, and to identify
forcing mechanisms of the reconstructed regional climate variability on seasonal to
centennial timescales.

2 Materials and Methods

In the southern Caribbean Sea (Bonaire), fossil annually-banded Diploria strigosa
corals were drilled. Screening for diagenesis indicates the aragonitic coral skeletons
are well-preserved (Giry et al. 2010a , 2012 ). Corals were microsampled at
approximately monthly resolution (Giry et al. 2010b ) and analyzed for Sr/Ca (proxy
for temperature) and

18 O).
The records provide monthly resolved reconstructions of sea-surface temperature
(SST) and

18 O (proxy re

δ ecting both temperature and seawater δ

18 O seawater (proxy for sea-surface salinity (SSS)) for snapshots since
the mid-Holocene. Corals were dated by the 230 Th/U-method and provide a total of
*

δ

300 years of record. Individual time windows reach up to 68 years in length
(Giry et al. 2012 , 2013 ).
In the northern Caribbean Sea (Cuba), stalagmites were recovered from two caves
(Dos Anas, Santo Tomas). Three stalagmites were dated by the 230 Th/U-method