Rapid climate change and conditional instability of the glacial deep ocean from the thermobaric effect and geothermal heating

被引:58
作者
Adkins, JF
Ingersoll, AP
Pasquero, C
机构
[1] CALTECH, Dept Geol & Planetary Sci, MS 100 23, Pasadena, CA 91125 USA
[2] CALTECH, Dept Geol & Planetary Sci, MS 150 21, Pasadena, CA 91125 USA
基金
美国国家科学基金会;
关键词
D O I
10.1016/j.quascirev.2004.11.005
中图分类号
P9 [自然地理学];
学科分类号
0705 ; 070501 ;
摘要
Previous results from deep-sea pore fluid data demonstrate that the glacial deep ocean was filled with salty, cold water from the South. This salinity stratification of the ocean allows for the possible accumulation of geothermal heat in the deep-sea and could result in a water column with cold fresh water on top of warm salty water and with a corresponding increase in potential energy. For an idealized 4000 dbar two-layer water column, we calculate that there are similar to 10(6) J/m(2) (similar to 0.2 J/kg) of potential energy available when a 0.4 psu salinity contrast is balanced by a similar to 2 degrees C temperature difference. This salt-based storage of heat at depth is analogous to Convectively Available Potential Energy (CAPE) in the atmosphere. The "thermobaric effect" in the seawater equation of state can cause this potential energy to be released catastrophically. Because deep ocean stratification was dominated by salinity at the Last Glacial Maximum (LGM), the glacial climate is more sensitive to charging this "thermobaric capacitor" and can plausibly explain many aspects of the record of rapid climate change. Our mechanism could account for the grouping of Dansgaard/Oeschger events into Bond Cycles and for the different patterns of warming observed in ice cores from separate hemispheres. (c) 2004 Elsevier Ltd. All rights reserved.
引用
收藏
页码:581 / 594
页数:14
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