Contributions of Interdecadal Pacific Oscillation and Atlantic Multidecadal Oscillation to Global Ocean Heat Content Distribution

TitleContributions of Interdecadal Pacific Oscillation and Atlantic Multidecadal Oscillation to Global Ocean Heat Content Distribution
Publication TypeJournal Article
Year of Publication2018
JournalJournal of Climate
Volume31
Number3
Pages1227-1244
Date Published01/2018
Abstract / Summary

Regional sea surface temperature (SST) mode variabilities, especially the La Niña-like Pacific Ocean temperature pattern known as the negative phase of the Interdecadal Pacific Oscillation (IPO), and the associated heat redistribution within the ocean are the leading mechanisms explaining the recent global warming hiatus. Here we use the Community Earth System Model (CESM) version 1, to examine how different phases of two leading decadal timescale SST modes, namely the IPO and the Atlantic Multidecadal Oscillation (AMO), contribute to heat redistribution in the global ocean in the absence of time evolving external forcings. Our results show that both the IPO and AMO contribute a similar magnitude to global mean surface temperature and ocean heat redistribution. Both modes contribute warmer surface temperature and higher upper ocean heat content in their positive phase, and the reverse in their negative phase. Regionally, patterns of ocean heat distribution in the upper few hundred meters of the tropical and subtropical Pacific Ocean depend highly on the IPO phase via the IPO associated changes in the subtropical cell. In the Atlantic, ocean heat content is primarily associated with the state of the AMO. The interconnections between the IPO, AMO and global ocean heat distribution are established through the atmospheric bridge and the Atlantic Meridional Overturning Circulation. An in-phase variant of the IPO and AMO can lead to much higher surface temperatures and heat content changes than an out of phase variation. This result suggests that changes in the IPO and AMO are potentially capable of modulating externally forced SST and heat content trends.

URLhttp://dx.doi.org/10.1175/jcli-d-17-0204.1
DOI10.1175/jcli-d-17-0204.1
Journal: Journal of Climate
Year of Publication: 2018
Volume: 31
Number: 3
Pages: 1227-1244
Date Published: 01/2018

Regional sea surface temperature (SST) mode variabilities, especially the La Niña-like Pacific Ocean temperature pattern known as the negative phase of the Interdecadal Pacific Oscillation (IPO), and the associated heat redistribution within the ocean are the leading mechanisms explaining the recent global warming hiatus. Here we use the Community Earth System Model (CESM) version 1, to examine how different phases of two leading decadal timescale SST modes, namely the IPO and the Atlantic Multidecadal Oscillation (AMO), contribute to heat redistribution in the global ocean in the absence of time evolving external forcings. Our results show that both the IPO and AMO contribute a similar magnitude to global mean surface temperature and ocean heat redistribution. Both modes contribute warmer surface temperature and higher upper ocean heat content in their positive phase, and the reverse in their negative phase. Regionally, patterns of ocean heat distribution in the upper few hundred meters of the tropical and subtropical Pacific Ocean depend highly on the IPO phase via the IPO associated changes in the subtropical cell. In the Atlantic, ocean heat content is primarily associated with the state of the AMO. The interconnections between the IPO, AMO and global ocean heat distribution are established through the atmospheric bridge and the Atlantic Meridional Overturning Circulation. An in-phase variant of the IPO and AMO can lead to much higher surface temperatures and heat content changes than an out of phase variation. This result suggests that changes in the IPO and AMO are potentially capable of modulating externally forced SST and heat content trends.

DOI: 10.1175/jcli-d-17-0204.1
Citation:
Hu, Z, A Hu, and Y Hu.  2018.  "Contributions of Interdecadal Pacific Oscillation and Atlantic Multidecadal Oscillation to Global Ocean Heat Content Distribution."  Journal of Climate 31(3): 1227-1244.  https://doi.org/10.1175/jcli-d-17-0204.1.