Opposite response modes of NADW dynamics to obliquity forcing during the late Paleogene SCIE SCOPUS

Cited 1 time in WEB OF SCIENCE Cited 1 time in Scopus
Title
Opposite response modes of NADW dynamics to obliquity forcing during the late Paleogene
Author(s)
Lee, Hojun; Jo, Kyoung-nam; Hyun, Sangmin
KIOST Author(s)
Hyun, Sang Min(현상민)
Publication Year
2020-08-06
Abstract
Although the responses of North Atlantic Deep Water (NADW) is deeply connected to orbital rhythms, those under different tectonic and atmospheric boundary conditions remain unknown. Here, we report suborbitally resolved benthic foraminiferal stable isotope data from J-anomaly Ridge in the North Atlantic from ca. 26.4-26.0 Ma. Our results indicate that the formation of NADW during that time interval was increased during the obliquity-paced interglacial periods, similar to in the Plio-Pleistocene. During the late Oligocene, the interglacial poleward shifts of the stronger westerlies in the southern hemisphere, which occurred due to the higher thermal contrasts near the upper limit of the troposphere, reinforced the Antarctic Circumpolar Current (ACC) and, in turn, the Atlantic meridional overturning circulation (AMOC). However, such a response mode in deep ocean circulation did not occur during the middle Eocene because of different tectonic boundary conditions and the immature states of the ACC. Instead, the middle Eocene interglacial conditions weakened the formation of the proto- type NADW due to less heat loss rate in high-latitude regions of the North Atlantic during high obliquity periods. Our findings highlight the different responses of deep ocean circulation to orbital forcing and show that climate feedbacks can be largely sensitive to boundary conditions.
ISSN
2045-2322
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/32921
DOI
10.1038/s41598-020-70020-2
Bibliographic Citation
SCIENTIFIC REPORTS, v.10, no.1, 2020
Publisher
NATURE RESEARCH
Subject
ATLANTIC DEEP-WATER; WESTERN NORTH-ATLANTIC; OCEAN CIRCULATION; DRAKE PASSAGE; SEA-ICE; EOCENE; NEWFOUNDLAND; TEMPERATURE; VARIABILITY; ANTARCTICA
Type
Article
Language
English
Document Type
Article
Publisher
NATURE RESEARCH
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