Biological and Environmental Research - Earth and Environmental System Sciences
Earth and Environmental System Modeling

The Role of the PMOC in Modulating the Deglacialshift of the ITCZ

TitleThe Role of the PMOC in Modulating the Deglacialshift of the ITCZ
Publication TypeJournal Article
Year of Publication2015
AuthorsLiu, Wei, and Hu Aixue
JournalClimate Dynamics
Volume45
Pages3019-3034
Abstract / Summary

Based on an energy-constraint framework, the effect of the Pacific meridional overturning circulation (PMOC) has been investigated on the meridional shift of the intertropical convergence zone (ITCZ). During Heinrich Event 1, the global ITCZ displaces southward in response to a shutdown of the Atlantic meridional overturning circulation (AMOC). However, the PMOC resumes and induces an enhanced northward meridional heat transport (MHT). Further analyses show that the resumption of the PMOC and its associated MHT can relieve the decrease of oceanic cross-equatorial heat transport by the collapsed AMOC and lower the compensating decline of atmospheric cross-equatorial meridional heat transport by 0.09PW, leading to an offset of the southward shift of the global ITCZ by 0.5°. Regionally the developed PMOC does not affect the southward movement of the Atlantic ITCZ much since the latter is dominated by the collapsed AMOC that induces the change of Atlantic MHT. In contrast, the PMOC-induced northward heat transport largely abates the hemispheric temperature contrast in the tropical Pacific and reduces the southward ITCZ shift by as much as 5° in the eastern Pacific.

URLhttps://doi.org/10.1007/s00382-015-2520-6
DOI10.1007/s00382-015-2520-6
Journal: Climate Dynamics
Year of Publication: 2015
Volume: 45
Pages: 3019-3034
Publication Date: 02/2015

Based on an energy-constraint framework, the effect of the Pacific meridional overturning circulation (PMOC) has been investigated on the meridional shift of the intertropical convergence zone (ITCZ). During Heinrich Event 1, the global ITCZ displaces southward in response to a shutdown of the Atlantic meridional overturning circulation (AMOC). However, the PMOC resumes and induces an enhanced northward meridional heat transport (MHT). Further analyses show that the resumption of the PMOC and its associated MHT can relieve the decrease of oceanic cross-equatorial heat transport by the collapsed AMOC and lower the compensating decline of atmospheric cross-equatorial meridional heat transport by 0.09PW, leading to an offset of the southward shift of the global ITCZ by 0.5°. Regionally the developed PMOC does not affect the southward movement of the Atlantic ITCZ much since the latter is dominated by the collapsed AMOC that induces the change of Atlantic MHT. In contrast, the PMOC-induced northward heat transport largely abates the hemispheric temperature contrast in the tropical Pacific and reduces the southward ITCZ shift by as much as 5° in the eastern Pacific.

DOI: 10.1007/s00382-015-2520-6
Citation:
Liu, W, and A Hu.  2015.  "The Role of the PMOC in Modulating the Deglacialshift of the ITCZ."  Climate Dynamics 45: 3019-3034.  https://doi.org/10.1007/s00382-015-2520-6.