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Global equatorial sea-surface temperatures over the last 150,000 years: An update from foraminiferal elemental analysis

DRS at CSIR-National Institute of Oceanography

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Title Global equatorial sea-surface temperatures over the last 150,000 years: An update from foraminiferal elemental analysis
 
Creator Saraswat, R.
 
Subject sea-surface temperatures
global climate
foraminifera
interglacial
 
Description Solar insolation changes are amongst various factors that affect sea-surface temperature (SST) which in turn modulate global climate. Out of all the oceanic regions, equatorial region receives the maximum solar insolation and thus is the locale for the warmest waters. However, how the equatorial SST affects global climate, is still not clear. Long-term past seawater temperature records are required to understand the effect of temporal changes in equatorial SST on the global climate. Various techniques are used to estimate past seawater temperatures. Here, the equatorial SSTs of the last 150,000 years BP as estimated from Mg/Ca ratio of the foraminiferal shells, have been compiled in order to get an update of the past SST changes in the equatorial region. It is inferred that the average cooling during the Last Glacial Maximum (LGM) (the interval dated from approx. 19-23 kyr BP during the last glacial period, when the ice-sheets covered maximum area) was approx. 2.3 degrees C as compared to the Holocene. The LGM-Holocene SST difference was not uniform throughout the studied cores, which implies that the surface equatorial temperature gradient during LGM was different than that at present. The equatorial surface waters were warmest during marine isotopic stage (MIS) 5.5, even warmer than that at present. However, the pattern of cooling and amount of drop in surface temperature during various substages of MIS 5 was not uniform throughout the equatorial oceans. During MIS 4, several regions of the surface equatorial ocean were warmer than that during MIS 3. The study further shows that surface equatorial oceans during MIS 3 were as cold as during MIS 2
 
Date 2011-04-29T09:47:47Z
2011-04-29T09:47:47Z
2011
 
Type Journal Article
 
Identifier Current Science, vol.100(8); 2011; 1201-1206
http://drs.nio.org/drs/handle/2264/3845
 
Language en
 
Rights Copyright [2011]. All efforts have been made to respect the copyright to the best of our knowledge. Inadvertent omissions, if brought to our notice, stand for correction and withdrawal of document from this repository.
 
Publisher Current Science Association