R. Klein et al., EVALUATING SOUTHERN RED-SEA CORALS AS A PROXY RECORD FOR THE ASIAN MONSOON, Earth and planetary science letters, 148(1-2), 1997, pp. 381-394
Coral palaeoclimatic studies are under way at many sites throughout th
e wet tropics. However, arid environments have received less attention
, Here we report a high-resolution, 63 yr record of coral delta(18)O a
nd delta(13)C extracted from a Porites colony from the Dahlak Archipel
ago, off the Eritrean coast, in the southern Red Sea. The annual cycle
s of the coral delta(18)O and delta(13)C are inversely related while t
heir inter-annual variations show a strong positive correlation, with
similar inter-decadal trends. Inter-annual variations in coral delta(1
8)O show a relatively weak correlation with the southern Red Sea SST,
but are strongly correlated with the Indian Ocean SST, especially on t
he decadal time-scale. The range of the inter-annual variations in the
coral delta(18)O is high compared to changes in local SST, due to the
amplifying effect of simultaneous changes in water isotopic compositi
on, Due to this amplification of the climate signal the coral provides
a better indication of regional oceanographic behaviour than the loca
l SST record, The northeast monsoon signal in the coral delta(18)O dom
inates the mean annual signal and shows the best correlation with the
instrumental data sets. It appears that variations in the coral delta(
18)O are controlled mainly by variations in the intensity of surface w
ater influx from the Indian Ocean to the Red Sea during the winter nor
theast monsoon. Of particular significance is that the decadal time-sc
ale variations in the coral skeletal delta(18)O are closely correlated
with both the Indian Ocean SST and with variations in the Pacific-bas
ed Southern Oscillation index, That is, isotopically light coral skele
ton, indicating strong NE monsoon Red Sea inflow, correlates with peri
ods of high Indian Ocean SST and with predominantly negative (El Nino)
phases of the Southern Oscillation, The simultaneous nature of inter-
decadal changes in Asian monsoon and ENSO behaviour suggest pan-Indo-P
acific tropical climate reorganisation and evolution.