I’ve moved to WordPress. This post can now be found at Atlantic Multidecadal Oscillation Index Reconstruction
#############INTRODUCTION
The Climate Reconstruction webpage…
http://www.ncdc.noaa.gov/paleo/recons.html…
of the NOAA Paleoclimatology Program and World Data Center for Paleoclimatology, Boulder contains a number of multi-century SST anomaly reconstructions. Though I posted the AMO reconstruction dataset in an earlier thread, SST Reconstructions, I thought it deserved an individual post. So what I’ve done in the following is presented the write-up provided by NOAA, with graphs trailing.
A link to the paper:
http://www.nrmsc.usgs.gov/files/norock/products/GCC/GeophysResLetters_Gray_04.pdf
NOTE
Keep in mind that the AMO Reconstruction data presented at the end of this post is not the same as the AMO presented by the NOAA ESRL. The NOAA ESRL AMO data is detrended North Atlantic SST data. The long-term reconstruction of the AMO has not been detrended. It is “the 10-yr moving average of annual SSTA values. Values are reported as standard deviations.”
NOAA WRITE-UP
Link:
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/amo-gray2004.txt
NAME OF DATA SET: Atlantic Multidecadal Oscillation (AMO) Index Reconstruction
LAST UPDATE: 10/2004 (Original Receipt by WDC Paleo)
CONTRIBUTORS: Stephen Gray and Julio Betancourt, USGS Desert Laboratory; Lisa Graumlich and Greg Pederson, Big Sky Institute, Montana State University.
IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2004-062
SUGGESTED DATA CITATION: Gray, S.T., et al.. 2004.Atlantic Multidecadal Oscillation (AMO) Index Reconstruction.IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series #2004-062. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.
ORIGINAL REFERENCE: Gray, S.T., L.J. Graumlich, J.L. Betancourt, and G.T. Pederson. 2004.
A tree-ring based reconstruction of the Atlantic Multidecadal Oscillation since 1567 A.D. Geophysical Research Letters, 31:L12205, doi:10.1029/2004GL019932.
ABSTRACT:
We present a tree-ring based reconstruction of the Atlantic Multidecadal Oscillation (AMO) which demonstrates that strong, low-frequency (60–100 yr) variability in basin-wide (0–70°N) sea surface temperatures (SSTs) has been a consistent feature of North Atlantic climate for the past five centuries. Intervention analysis of reconstructed AMO indicates that 20th century modes were similar to those in the preceding ~350 yr, and wavelet spectra show robust multidecadal oscillations throughout the reconstruction. Though the exact relationships between low-frequency SST modes, higher frequency (~7–25 yr) atmospheric modes (e.g., North Atlantic Oscillation/Arctic Oscillation), and terrestrial climates must still be resolved, our results confirm that the AMO should be considered in assessments of past and future Northern Hemisphere climates.
GEOGRAPHIC REGION: North Atlantic Ocean (0-70º N)
PERIOD OF RECORD: 1567-1990 AD
FUNDING SOURCES: National Science Foundation (USA), U.S. Geological Survey.
DESCRIPTION:
Reconstruction of North Atlantic sea surface temperature anomalies and the Atlantic Multidecadal Oscillation index based on tree ring chronologies from eastern North America, western Europe, Scandinavia and the Middle East.
These data represent a tree-ring based reconstruction of annual sea surface temperature anomalies (SSTA) for the North Atlantic Ocean (0-70º) and a reconstruction of the Atlantic Multidecadal Oscillation (AMO) index derived from these SSTA values. The AMO is the leading mode of low frequency, North Atlantic SST variability. Over the instrumental period (1856-Present) the AMO exhibited a 65-80 yr cycle (0.4 º C range), with warm phases at roughly 1860-1880 and 1930-1960 and cool phases during 1905-1925 and 1970-1990. The AMO appears to have returned to a warm phase beginning in the mid 1990s.
The AMO has been linked to multi-year precipitation anomalies over North America, and appears to modulate the strength of El Niño-Southern Oscillation (ENSO) teleconnections over large portions of the Northern Hemisphere. Multidecadal variability in the North Atlantic is also thought to play a role in Atlantic hurricane formation, rainfall over the Caribbean and northeastern Brazil, African drought frequency, and winter temperatures in Europe. Instrumental observations capture only two full cycles of the AMO, so a need exists for developing proxies to assess low-frequency North Atlantic SST variations and their climatic effects.
These SSTA and AMO reconstructions span the period from A.D. 1567 to 1990 and were developed using 12 tree-ring records from eastern North America, western Europe, Scandinavia, and the Middle East. We first reconstructed annual SSTA values for the North Atlantic and then smoothed this time series with a 10-yr moving average to produce the Atlantic Multidecadal Oscillation index. Correlations between the observed and reconstructed SSTA and AMO values were high (r = 0.64 and 0.81, respectively) and numerous tests confirmed that the model has significant skill in predicting SSTA values.
GRAPHS
http://i48.tinypic.com/241ml5g.pngNorth Atlantic SST Reconstruction
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http://i47.tinypic.com/ekkhuc.pngAMO Reconstruction “The AMO index is the 10-yr moving average of annual SSTA values. Values are reported as standard deviations”
