Overview Climate Reconstruction Codes

Different large scale reconstruction methods:

Bradley and Jones (The Holocene 1993)
Overpeck et al. (Science 1997)
Mann et al. (Nature 1998, GRL 1999)
Jones et al. (The Holocene 1998)
Crowley and Lowery (Ambio 2000)
Briffa et al. (Quat. Sci. Rev, 2000)
Huang et al. (Nature 2000)
Briffa et al. (JGR 2001)
Esper et al. (Science 2002) [difficult to duplicate because its based on a particular separation of tree ring records]
Mann and Jones (2003)
Rutherford et al. (J Climate 2005 (in press))
Moberg et al. (Nature 2005)

'New' methods applied to paleo problems:

Spherical Wavelets (Oh/Ammann/Naveau)
Mode oriented field reconstructions > Regional reconstructions (Wahl/Ammann)
?

There are also important regional reconstructions that are based on multi-proxy approaches, but these we should get at later. However, we need to remember that these regional analyses are important because of the demand of regional climate impact evaluation. (Luterbacher, Casty: Europe; Cook: N-Atlantic, Pacific; Evans, Pacific)

We are dealing with a number of problems:

sampling issues (spatial and temporal)
spatial weighting (local vs regional signals/noise)
clean separation of frequencies to prevent de- or inflation
short calibration and limited verification
uncertainty in forcings (also derived from proxy data)

The Input data we should have ready for each:

original proxy set to reproduce original
largest proxy set from most recent reconstructions
GCM output from runs - forced (various levels) and unforced
other artificial data to test certain properties

Fortunately, the various reconstruction techniques offer different approaches and thus span a bunch of the uncertainties. The question is which uncertainties are always the same and how important are they?

The reconstructions should help us provide:

comparison of N-Hemisphere temperature between reconstruction techniques (duplicate plot in attached Kerr article, originally from Briffa and Osborn, Science 2002)
comparison of N-Hem temperatures in different frequency bands (compare to single example in Esper et al., EOS 2004)

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Caspar Ammann

Last modified: Tue May 10 20:23:55 MDT 2005