New thoughts about the Cretaceous climate and oceans.

Hay, William W. and Flögel, Sascha (2012) New thoughts about the Cretaceous climate and oceans. Earth-Science Reviews, 115 (4). pp. 262-272. DOI 10.1016/j.earscirev.2012.09.008.

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Abstract

Several new discoveries suggest that the climate of the Cretaceous may have been more different from that of today than has been previously supposed. Detailed maps of climate-sensitive fossils and sediments compiled by Nicolai Chumakov and his colleagues in Russia indicate widespread aridity in the equatorial region during the Early Cretaceous. The very warm ocean temperatures postulated for the Mid-Cretaceous by some authors would likely have resulted in unacceptable heat stress for land plants at those latitudes, however, and may be flawed.

Seasonal reversals of the atmospheric pressure systems in the Polar Regions are an oversimplification. However, the seasonal pressure differences between 30° and 60° latitude became quite pronounced, being more than 25 hPa in winter and less than 10 hPa in summer. This resulted in inconstant winds, affecting the development of the gyre-limiting frontal systems that control modern ocean circulation. The idea of Hasegawa et al. (2012) who suggest a drastic reduction in the size of the Hadley cells during the warm Cretaceous greenhouse is supported by several numerical climate simulations. Rapid contraction of the Hadley cell such that its sinking dry air occurs at 15° N latitude rather than 30° N is proposed to occur at a threshold of 1000 ppmv CO2 in the atmosphere. This change will probably be reached in the next century.
Keywords

Document Type: Article
Additional Information: WOS:000313609000004
Keywords: Cretaceous; Paleoclimate; Paleotemperature; Atmospheric circulation; Hadley cells; SEASONAL CYCLE; CIRCULATION; SEA; CO2; TEMPERATURE; EPISODES; EDDIES; RECORD; MIDDLE
Research affiliation: OceanRep > SFB 754 > A7
OceanRep > SFB 754
OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1016/j.earscirev.2012.09.008
ISSN: 0012-8252
Projects: SFB754, Future Ocean
Date Deposited: 11 Dec 2012 09:08
Last Modified: 23 Sep 2019 19:58
URI: http://oceanrep.geomar.de/id/eprint/19648

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