skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Optimal excitation of AMOC decadal variability: Links to the subpolar ocean

Publication Date:
Sponsoring Org.:
OSTI Identifier:
Grant/Contract Number:
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Progress in Oceanography
Additional Journal Information:
Journal Volume: 132; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-06-23 15:56:09; Journal ID: ISSN 0079-6611
Country of Publication:
United Kingdom

Citation Formats

Sévellec, Florian, and Fedorov, Alexey V. Optimal excitation of AMOC decadal variability: Links to the subpolar ocean. United Kingdom: N. p., 2015. Web. doi:10.1016/j.pocean.2014.02.006.
Sévellec, Florian, & Fedorov, Alexey V. Optimal excitation of AMOC decadal variability: Links to the subpolar ocean. United Kingdom. doi:10.1016/j.pocean.2014.02.006.
Sévellec, Florian, and Fedorov, Alexey V. 2015. "Optimal excitation of AMOC decadal variability: Links to the subpolar ocean". United Kingdom. doi:10.1016/j.pocean.2014.02.006.
title = {Optimal excitation of AMOC decadal variability: Links to the subpolar ocean},
author = {Sévellec, Florian and Fedorov, Alexey V.},
abstractNote = {},
doi = {10.1016/j.pocean.2014.02.006},
journal = {Progress in Oceanography},
number = C,
volume = 132,
place = {United Kingdom},
year = 2015,
month = 3

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.pocean.2014.02.006

Citation Metrics:
Cited by: 7works
Citation information provided by
Web of Science

Save / Share:
  • Numerous analyses of relatively short (25-30 years in length) time series of the observed surface temperature of the tropical Atlantic Ocean have indicated the possible existence of decadal timescale variability. It was decided to search for such variability in 100-yr time series of sea surface temperature (SST) measured aboard ships and available in the recently published Global Ocean Surface Temperature Atlas (GOSTA). Fourier and singular spectrum analyses of the GOSTA SST time series averaged over 11 subregions, each approximately 1 x 10{sup 6}km{sup 2} in area, show that pronounced quasi-oscillatory decadal ({approximately}-20 yr) and multidecadal ({approximately}30-40 yr) timescale variability existsmore » in the GOSTA dataset over the tropical Atlantic. Motivated by the above results, SST variability was investigated in a 200-yr integration of a global model of the coupled oceanic and atmospheric general circulations developed at the geophysical Fluid Dynamics Laboratory (GFDL). The second 100 yr of SST in the coupled model`s tropical Atlantic region were analyzed with a variety of techniques. Analyses of SST time series, averaged over approximately the same subregions as the GOSTA time series, showed that the GFDL SST anomalies also undergo pronounced quasi-oscillatory decadal and multidecadal variability but at somewhat shorter timescales than the GOSTA SST anomalies. Further analyses of the horizontal structures of the decadal timescale variability in the GFDL coupled model showed the existence of two types of variability in general agreement with results of the GOSTA SST time series analyses. One type, characterized by timescales between 8 and 11 yr, has high spatial coherence within each hemisphere but not between the two hemispheres of the tropical Atlantic. A second type, characterized by timescales between 12 and 20 yr, has high spatial coherence between the two hemispheres. 31 refs., 14 figs., 3 tabs.« less
  • As Patterson and coworkers have shown, most of the lead in the modern ocean and atmosphere is of anthropogenic origin. Reductions in the utilization of leaded gasoline over the past two decades should decrease lead deposition from the atmosphere in remote locations. The search for trends in Pb deposition within a single decade is bedeviled by large-amplitude short-term variability due to the inherent noisiness of the atmosphere/ocean system. The authors find that, over the course of a year, lead concentrations in the surface waters of the western North Atlantic Ocean are variable (order of magnitude). In the western North Atlantic,more » [sup 210]Pb normalization minimizes this problem because [sup 210]Pb and Pb sources are spatially correlated and continental [sup 210]Pb emissions are constant. It is clear the Pb in surface waters of the western North Atlantic has decreased by a factor of 4 during the 1980s. [sup 210]Pb normalization does not help in the Arctic because stable Pb and [sup 210]Pb are not spatially correlated. Because of the order-of-magnitude variability in Greenland snow Pb linked to annual cycles, any discontinuous time series is likely to be affected by the phenomenon of aliasing. Aliasing makes it difficult to determine if there is a trend in Pb deposition in central Greenland during the 1980s; present evidence suggests that the reduction in Pb concentration in snow during the 1980s is less than a factor of two; certainly quite a bit less than observed in the western North Atlantic and less than the factor of >7 reduction in leaded gasoline utilization in the United States during the decade. Although the authors expect that decadal-scale trends in the 1970s and 1980s are in fact occurring due to the phasing out of leaded gasoline, the reported magnitude of decadal-scale trends should be regarded with some reservation until confirmed by independent samplings.« less
  • The climate variability in the North Atlantic sector is investigated in a 325-yr investigated in a 325-yr integration of the ECHAM1/LSG coupled ocean-atmosphere general circulation model. At the interannual timescale, the coupled model behaves realistically and sea surface temperature (SST) anomalies arise as a response of the oceanic surface layer to the stochastic forcing by the atmosphere, with the heat exchanges both generating and damping the SST anamalies. 45 refs., 16 figs.