Can we trust proxy‐based NAO index reconstructions?

Schmutz, Christoph; Luterbacher, Jürg; Gyalistras, Dimitrios; Xoplaki, Elena; Wanner, Heinz

doi:10.1029/1999gl011045

Cited by 168 publications

(83 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Possible physical causes for time-dependent relationships have also been proposed (Schmutz et al 2000;Cullen et al 2000;LUT). Ancient changes in the locations of the NAO centers, similar to the recent shift of the NAO in the 1970s (Hilmer and Jung 2000), would disturb the stationarity assumption of the NAO-proxy relations.…”

Section: Discussionmentioning

confidence: 99%

Scale-Dependent Reconstruction of the NAO Index

Timm¹,

Ruprecht²,

Kleppek³

2004

J. Climate

View full text Add to dashboard Cite

A method is presented to reconstruct decadal variations of the North Atlantic Oscillation (NAO). The spectral characteristics of the NAO on time scales of decades and longer are of particular interest for the understanding of North Atlantic ocean-atmosphere interactions. The reconstruction is based on a transfer model calibration that uses bandpass-filtered time series. The maximum overlap discrete wavelet transform (MODWT) is applied for decomposing the time series variance into different time scales. A total of 43 proxies, including Greenland ice cores and European tree-ring chronologies, are selected and regionally grouped providing four independent reconstructions for the period 1700-1978. The mean reconstruction agrees well with two recently published reconstructions during most of the time period. However, there are considerable differences in the earliest part before 1750. Running correlations between the reconstructions indicate that time-dependent relations exist among the different NAO reconstructions. The results suggest that the geographical distribution of proxies strongly affects the reconstruction and could explain some of the apparent discrepancies among the reconstructions recently published in literature. In the early eighteenth century, external forcing (solar, volcanic) seems to mask the NAO signature within the proxies.

show abstract

Section: Discussionmentioning

confidence: 99%

Scale-Dependent Reconstruction of the NAO Index

Timm¹,

Ruprecht²,

Kleppek³

2004

J. Climate

View full text Add to dashboard Cite

show abstract

“…[3] Existing NAO reconstructions based on direct instrumental [Jones et al, 1997] and documentary records of atmospheric pressure [Luterbacher et al, 2002], supplemented by proxy records of rainfall and/or temperature variations from tree rings [Cook et al, 1998] and ice cores [Appenzeller et al, 1998;Barlow, 2001;Vinther et al, 2003] extend pre-instrumental NAO behaviour back to 1429 A.D.; however, considerable disagreement exists between reconstructions [Schmutz et al, 1999]. Recently, NAO variability on longer timescales was inferred from westerly transported fine-grained loess deposits that exhibit increased accumulation during glacial periods [e.g., Vandenberghe et al, 2006].…”

Section: Introductionmentioning

confidence: 99%

Spatial variability in the European winter precipitation δ¹⁸O‐NAO relationship: Implications for reconstructing NAO‐mode climate variability in the Holocene

Baldini¹,

McDermott²,

Foley³

et al. 2008

Geophysical Research Letters

106

View full text Add to dashboard Cite

“…This could imply that European temperature-sensitive proxies are not adequate for NAOI reconstructions. We suggest that this might be one of the reasons for the disagreement among the different NAOI reconstructions put forward in the literature to date [Schmutz et al, 1999]. Table 1 …”

Section: Discussionmentioning

confidence: 95%

“…The possible divergences in the reconstructions caused by the use of annual or monthly means are not considered here [Appenzeller et al, 1998;Cook et al, 1998;Luterbacher et al, 1999].…”

Section: Climate Model and Statistical Modelmentioning

confidence: 99%

See 1 more Smart Citation

Are temperature‐sensitive proxies adequate for North Atlantic Oscillation reconstructions?

Zorita¹,

Gonzalez-Rouco

2002

Geophysical Research Letters

View full text Add to dashboard Cite

[1] Reconstructions of the North Atlantic Oscillation Index (NAOI) for the last centuries are mostly based on statistical models linking this index with proxy records. The underlying assumption is that the relationship between the NAO and the proxy records is stable in time and independent of time scale. This assumption might not be physically substantiated, since at time scales of centuries, other processes, such as solar variability, might disturb the link between the NAOI and temperature-sensitive indicators. The statistical approach for NAOI reconstructions was tested using a climate simulation with a climate model driven by the external forcing of the last 490 years, as a surrogate climate. Two kinds of indicators were tested, air temperature and precipitation. It was found that the NAOI reconstructions based on precipitation are more reliable than the reconstructions based on temperature. Furthermore, the choice of geographical box has a nonnegligible influence on the reconstructed NAOI.

show abstract

Can we trust proxy‐based NAO index reconstructions?

Cited by 168 publications

References 19 publications

Scale-Dependent Reconstruction of the NAO Index

Scale-Dependent Reconstruction of the NAO Index

Spatial variability in the European winter precipitation δ¹⁸O‐NAO relationship: Implications for reconstructing NAO‐mode climate variability in the Holocene

Are temperature‐sensitive proxies adequate for North Atlantic Oscillation reconstructions?

Contact Info

Product

Resources

About

Can we trust proxy‐based NAO index reconstructions?

Cited by 168 publications

References 19 publications

Scale-Dependent Reconstruction of the NAO Index

Scale-Dependent Reconstruction of the NAO Index

Spatial variability in the European winter precipitation δ18O‐NAO relationship: Implications for reconstructing NAO‐mode climate variability in the Holocene

Are temperature‐sensitive proxies adequate for North Atlantic Oscillation reconstructions?

Contact Info

Product

Resources

About

Spatial variability in the European winter precipitation δ¹⁸O‐NAO relationship: Implications for reconstructing NAO‐mode climate variability in the Holocene