Estimation of the SST response to anthropogenic and external forcing, and its impact on the Atlantic Multidecadal Oscillation and the Pacific Decadal Oscillation

Estimation of the SST response to anthropogenic and external forcing, and its impact on the... AbstractTwo large ensembles (LE) of historical climate simulations are used to compare how various statistical methods estimate the sea surface temperature (SST) changes due to anthropogenic and other external forcing, and how their removal affect the internally-generated Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO), and the SST footprint of the Atlantic meridional overturning circulation (AMOC). Removing the forced SST signal by subtracting the global mean SST (GM) or a linear regression on it (REGR) leads to large errors in the Pacific. Multi-dimensional ensemble empirical mode decomposition (MEEMD) and quadratic detrending only efficiently remove the forced SST signal in one LE, and cannot separate the short-term response to volcanic eruptions from natural SST variations. Removing a linear trend fares poorly. Two methods based on linear inverse modeling (LIM), one where the leading LIM mode represents the forced signal and another using optimal perturbation filter (LIMopt), perform consistently well. However, the first two LIM modes are sometimes needed to represent the forced signal, hence the more robust LIMopt is recommended. In both LE, the natural AMO variability seems largely driven by the AMOC in the subpolar North Atlantic, but not in the subtropics and tropics, and the scatter in AMOC-AMO correlation is large between individual ensemble members. In three observational SST reconstructions for 1900-2015, linear and quadratic detrending, MEEMD, and GM yield somewhat different AMO behavior, and REGR smaller PDO amplitudes. Based on LIMopt, only about 30% of the AMO variability is internally-generated, and more than 90% for the PDO. The natural SST variability contribution to global warming hiatus is discussed. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Climate American Meteorological Society

Estimation of the SST response to anthropogenic and external forcing, and its impact on the Atlantic Multidecadal Oscillation and the Pacific Decadal Oscillation

Loading next page...
 
/lp/ams/estimation-of-the-sst-response-to-anthropogenic-and-external-forcing-DFRH0Yrk0g
Publisher
American Meteorological Society
Copyright
Copyright © American Meteorological Society
ISSN
1520-0442
D.O.I.
10.1175/JCLI-D-17-0009.1
Publisher site
See Article on Publisher Site

Abstract

AbstractTwo large ensembles (LE) of historical climate simulations are used to compare how various statistical methods estimate the sea surface temperature (SST) changes due to anthropogenic and other external forcing, and how their removal affect the internally-generated Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO), and the SST footprint of the Atlantic meridional overturning circulation (AMOC). Removing the forced SST signal by subtracting the global mean SST (GM) or a linear regression on it (REGR) leads to large errors in the Pacific. Multi-dimensional ensemble empirical mode decomposition (MEEMD) and quadratic detrending only efficiently remove the forced SST signal in one LE, and cannot separate the short-term response to volcanic eruptions from natural SST variations. Removing a linear trend fares poorly. Two methods based on linear inverse modeling (LIM), one where the leading LIM mode represents the forced signal and another using optimal perturbation filter (LIMopt), perform consistently well. However, the first two LIM modes are sometimes needed to represent the forced signal, hence the more robust LIMopt is recommended. In both LE, the natural AMO variability seems largely driven by the AMOC in the subpolar North Atlantic, but not in the subtropics and tropics, and the scatter in AMOC-AMO correlation is large between individual ensemble members. In three observational SST reconstructions for 1900-2015, linear and quadratic detrending, MEEMD, and GM yield somewhat different AMO behavior, and REGR smaller PDO amplitudes. Based on LIMopt, only about 30% of the AMO variability is internally-generated, and more than 90% for the PDO. The natural SST variability contribution to global warming hiatus is discussed.

Journal

Journal of ClimateAmerican Meteorological Society

Published: Sep 8, 2017

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

Monthly Plan

  • Read unlimited articles
  • Personalized recommendations
  • No expiration
  • Print 20 pages per month
  • 20% off on PDF purchases
  • Organize your research
  • Get updates on your journals and topic searches

$49/month

Start Free Trial

14-day Free Trial

Best Deal — 39% off

Annual Plan

  • All the features of the Professional Plan, but for 39% off!
  • Billed annually
  • No expiration
  • For the normal price of 10 articles elsewhere, you get one full year of unlimited access to articles.

$588

$360/year

billed annually
Start Free Trial

14-day Free Trial