[OANNES Foro] A 12-Million-Year Temperature History of the Tropical Pacific Ocean (Not So Permanent El Niño)

[Mario Cabrejos]

Science 4 April 2014: 
Vol. 344 no. 6179 pp. 52-53 
DOI: 10.1126/science.1252246 

 

Not So Permanent El Niño

 
<http://www.sciencemag.org/search?author1=David+W.+Lea&sortspec=date&submit=
Submit> David W. Lea. Department of Earth Science, University of California,
Santa Barbara, CA 93109-9630, USA. E-mail:  <mailto:lea en geol.ucsb.edu>
lea en geol.ucsb.edu

 

Summary

Knowledge of the behavior of the tropical oceans under different climate
conditions is important for understanding not only past climate change but
also present and future global warming, especially given the recent finding
that the cool state of the equatorial Pacific might be the cause of the
current global warming hiatus (1). On page 84 of this issue, Zhang et al.
evaluate the long-term evolution of tropical Pacific sea surface
temperatures (SSTs) since 12 million years ago (2). They conclude that the
equatorial Pacific was warmer during the Pliocene (5.3 to 2.6 million years
ago) and late Miocene (12.0 to 5.3 million years ago) than it is today and
that the temperature difference between the eastern and western tropical
Pacific that is a fundamental characteristic of today's ocean was present
(although somewhat smaller than it is today) during these warmer time
intervals. 

/////////////////////////////////////////

Science 4 April 2014: 
Vol. 344 no. 6179 pp. 84-87 
DOI: 10.1126/science.1246172 

A 12-Million-Year Temperature History of the Tropical Pacific Ocean

 
<http://www.sciencemag.org/search?author1=Yi+Ge+Zhang&sortspec=date&submit=S
ubmit> Yi Ge Zhang
<http://www.sciencemag.org/content/344/6179/84.abstract#aff-1> 1,
<http://www.sciencemag.org/content/344/6179/84.abstract#corresp-1> *,
<http://www.sciencemag.org/search?author1=Mark+Pagani&sortspec=date&submit=S
ubmit> Mark Pagani
<http://www.sciencemag.org/content/344/6179/84.abstract#aff-1> 1,
<http://www.sciencemag.org/search?author1=Zhonghui+Liu&sortspec=date&submit=
Submit> Zhonghui Liu
<http://www.sciencemag.org/content/344/6179/84.abstract#aff-2> 2

1Department of Geology and Geophysics, Yale University, New Haven, CT 06511,
USA. 2Department of Earth Sciences, The University of Hong Kong, Hong Kong
SAR, China. *Corresponding author. E-mail:  <mailto:yige.zhang en yale.edu>
yige.zhang en yale.edu

 <http://www.sciencemag.org/content/344/6179/tab-abstract> Abstract

The appearance of permanent El Niño–like conditions prior to 3 million years
ago is founded on sea-surface temperature (SST) reconstructions that show
invariant Pacific warm pool temperatures and negligible equatorial zonal
temperature gradients. However, only a few SST records are available, and
these are potentially compromised by changes in seawater chemistry,
diagenesis, and calibration limitations. For this study, we establish new
biomarker-SST records and show that the Pacific warm pool was ~4°C warmer 12
million years ago. Both the warm pool and cold tongue slowly cooled toward
modern conditions while maintaining a zonal temperature gradient of ~3°C in
the late Miocene, which increased during the Plio-Pleistocene. Our results
contrast with previous temperature reconstructions that support the
supposition of a permanent El Niño–like state. 

 

 



---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com
------------ próxima parte ------------
Se ha borrado un adjunto en formato HTML...
URL: <http://lista.oannes.org.pe/pipermail/oannes-oannes.org.pe/attachments/20140403/940e88a8/attachment.html>