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Australia: The Land Where Time Began |
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Pliocene Sea
Surfaces Temperature High in Tropical Warm Pools In the
Atlantic and
Pacific oceans the
western warm pools are a critical source of heat and moisture for the
tropical climate system. The global mean temperatures have cooled 3-4oC
over the past 5 My, though present reconstructions of sea surface
temperatures have indicated that the warm pools remained at stable
temperatures over that period of time. It has been suggested, based on
this stability, that a thermostat-like mechanism has maintained
consistent tropical sea surface temperatures. In this study (O’Brien et
al.,)1 the
reconstructed sea surface
temperatures in the South China Sea, Caribbean Sea and western
equatorial Pacific Ocean for the past 5 My by the use of a combination
of Mg/Ca-, TEX86H- and Uk’/27-
proxies for surface temperatures. It was indicated by their data that
from about 5 to 2.5 Ma, over the period of the
Pliocene
warmth, the warm pools in the western Atlantic and western Pacific were
about 2oC warmer that the present temperatures of those warm
pools. Based on these results O’Brien et
al.,1 suggest that
the apparent lack of warmth indicated by the previous studies was an
artefact of low seawater Mg/Ca ratios in the oceans during the Pliocene.
When this bias is accounted for the data resulting from the present
study the sea surface temperatures did actually change in conjunction
with global mean temperatures, leading to the conclusion that in the
equatorial oceans of the Pliocene the temperature of the warm pools was
not limited by a thermostat-like mechanism.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |