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Ocean bottom pressure changes lead to a decreasing length‐of‐day in a warming climate
Author(s) -
Landerer Felix W.,
Jungclaus Johann H.,
Marotzke Jochem
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl029106
Subject(s) - climatology , climate change , oceanography , environmental science , lead (geology) , water mass , global warming , arctic , ocean bottom , geology , ocean heat content , ocean current , geomorphology , seismology
We use a coupled climate model to evaluate ocean bottom pressure changes in the IPCC‐A1B climate scenario. Ocean warming in the 21st and 22nd centuries causes secular oceanic bottom pressure anomalies. The essential feature is a net mass transfer onto shallow shelf areas from the deeper ocean areas, which exhibit negative bottom pressure anomalies. We develop a simple mass redistribution model that explains this mechanism. Regionally, however, distinct patterns of bottom pressure anomalies emerge due to spatially inhomogeneous warming and ocean circulation changes. Most prominently, the Arctic Ocean shelves experience an above‐average bottom pressure increase. We find a net transfer of mass from the Southern to the Northern Hemisphere, and a net movement of mass closer towards Earth's axis of rotation. Thus, ocean warming and the ensuing mass redistribution change the length‐of‐day by −0.12 ms within 200 years, demonstrating that the oceans are capable of exciting nontidal length‐of‐day changes on decadal and longer timescales.