SOAP Deliverable 15, Report on the interpretation of palaeodata using climate simulations
contributions from CRU, FUB, GKSS, University of Bern, and UDESAM
compiled by J. M. Jones [Author ID1: at Mon Jan 30 10:10:00 2006
]and [Author ID1: at Mon Jan 30 10:11:00 2006
]E. Zorita and[Author ID1: at Mon Jan 30 10:11:00 2006
] J. M. Jones[Author ID1: at Mon Jan 30 10:10:00 2006
], GKSS Research Centre
One of the main aims of the SOAP project is the comparison of climate model simulations and palaeoclimate proxy data. The combined analysis of proxy and GCM data is essential for reducing the uncertainties in estimates of natural climate variability, and for improving numerical models. It will help to better understand the interactions among the various components of the climate system, to estimate the relative contributions of natural and anthropogenic climate forcings to climate variability, and to make scenarios of future climatic changes more reliable.
The work on SO&P towards the interpretation of palaeodata using climate simulations has used the so-called pseudoproxy approach. This approach uses non-proxy data, either instrumental or model-simulated, to mimic the proxy data [Author ID2: at Mon Jan 30 13:39:00 2006
]. [Author ID2: at Mon Jan 30 13:39:00 2006
](Mann and Rutherford[Author ID3: at Fri Jan 27 16:04:00 2006
] GRL 29, doi10.1029/2001GL014554, 2001[Author ID3: at Fri Jan 27 16:04:00 2006
][Author ID2: at Mon Jan 30 13:27:00 2006
]2002[Author ID2: at Mon Jan 30 13:27:00 2006
]; Zorita[Author ID3: at Fri Jan 27 16:04:00 2006
] et al. 2003)[Author ID2: at Mon Jan 30 13:39:00 2006
], Gonzalez-Rouco and Legutke, J. Clim.16,1378-1390 (2003)[Author ID3: at Fri Jan 27 16:04:00 2006
][Author ID2: at Mon Jan 30 13:39:00 2006
])[Author ID2: at Mon Jan 30 13:39:00 2006
]. Within SOAP, a number of such GCM-based pseudo-proxy studies have been undertaken, where the simulation is used as a laboratory to test questions/hypotheses on climate reconstruction.
This report contains the publication where the work is published or in press, or a short report of work in progress. Below is a brief summary of the contributions, grouped by institution, followed by a table of contents and reference list containing the publications from the contributors, and publications cited in this introduction. Publications of the individual contributions are at the end of each contribution.
GKSS
Von Storch et al. (2004) used the pseudoproxy approach, applied to both the Erik[Author ID3: at Fri Jan 27 16:04:00 2006
]ECHO-G[Author ID3: at Fri Jan 27 16:04:00 2006
] simulation of the GKSS (hereafter Erik simulation)[Author ID3: at Fri Jan 27 16:08:00 2006
], and thenatural forcings and[Author ID3: at Fri Jan 27 16:04:00 2006
] all forcings simulations of HadCM3, to investigate the influence of noise on statistical reconstruction methods, including that of Mann et al. (1999), where it was found that past variations may have been at least a factor of two larger than indicated by empirical reconstructions. A commentary was provided on this work by Osborn and Briffa (2004) - see CRU below. Von Storch and Zorita (2005) also used the pseudoproxy method to address an issue of the Mann reconstruction method raised by McIntyre and McKitrick (2005) in the Erik simulation. The GKSS has also undertaken work together with Fidel González-Rouco of the Universidad Computense de Madrid. The first stage of this work was an analysis within the Erik simulation of the relationship between the terrestrial deep soil temperature and surface temperature (González-Rouco et al. 2003), a key relationship in borehole-based reconstruction of surface air temperature. In González-Rouco et al. (2006) forward models of borehole temperatures were applied to the Erik simulation and a control simulation with the ECHO-G model to test the borehole reconstruction methods.
CRU
Osborn and Briffa (2004) provided a commentary to von Storch et al. (2004) where they linked the systematic underestimation of low-frequency variability to the differing shapes of the variance spectra of the NH temperature and the pseudoproxy data, and thus suggest that for climate reconstructions to be optimal on all time scales, proxy data must have variance spectra similar to those of the climate data that they aim to reconstruct.
Osborn and Briffa, together with other co-authors (Rutherford et al., 2005), examined the sensitivity of[Author ID1: at Mon Jan 30 10:03:00 2006 ] temperature reconstructions to the use of different target variable (annual or seasonal temperature), target domain (hemispheric or extratropical) and reconstruction method. They found that w[Author ID1: at Mon Jan 30 10:04:00 2006 ]hen [Author ID1: at Mon Jan 30 10:05:00 2006 ]the differences in target variable and domain are accounted for, the differences in several reconstructions are small and that all reconstructions robustly indicate [Author ID1: at Mon Jan 30 10:05:00 2006 ]anomalous warm conditions in the 20[Author ID1: at Mon Jan 30 10:06:00 2006 ]th[Author ID1: at Mon Jan 30 10:06:00 2006 ] century, with respect to the past millennium.[Author ID1: at Mon Jan 30 10:06:00 2006 ]
FUB
The FUB investigated the influence of different decisions mak[Author ID3: at Fri Jan 27 16:05:00 2006
]d[Author ID3: at Fri Jan 27 16:05:00 2006
]e during the reconstruction process (Bürger et al. 2006) using the Erik simulation. They then investigated the influence of these decisions using the the proxy data of Mann et al. (year[Author ID3: at Fri Jan 27 16:05:00 2006
]1998[Author ID3: at Fri Jan 27 16:05:00 2006
]) (Bürger and Cubasch 2005). Both the model-based and proxy-based study found a wide spread of possible millennial temperature histories, which they attribute to the fact that that the training variations are not representative of the full millennium and that the [Author ID3: at Fri Jan 27 16:06:00 2006
]reconstruction methods are not-regularized.[Author ID3: at Fri Jan 27 16:07:00 2006
]. To actually compare the simulated and proxy-reconstructed Northern Hemisphere temperature histories, G. Bürger has correlated and regressed against the Northern Hemisphere annual mean land surface temperature anomalies as simulated in Erik and the HadCM3 simulation onto eight recent proxy based NH temperature reconstructions, where he finds that the ECHO-G simulation better fits the proxies than does the HadCM3 simulation.
University of Berne[Author ID3: at Fri Jan 27 16:07:00 2006
]
The University of Berne,[Author ID3: at Fri Jan 27 16:07:00 2006
] together with UDESAM (below) have utilized the pseudoproxy approach to investigate data quality issues of proxy-based reconstructions from their groups, in this case the reconstruction of European continental temperature of Luterbacher et al. (2004) in the Erik simulation. Küttel et al. page n investigated the skill of the reconstruction method, together with the dependency on the quality of the predictors and their availability over space and time.
UDESAM
The work of UDESAM used the pseudoproxy approach applied to the Erik simulation to investigate issues regarding a reconstruction of PDSI for the Mediterranean region for the period 1350-2000 AD using tree ring width and density records (Nicault et al. in preparation). They explored firstly the influence of a low number of proxies in their reconstructions, as in the early part of their reconstruction. Here they found that before 1600AD a large part of the reconstruction region has not enough information to produce a reliable reconstruction. They also investigated the influence of white noise in the pseudoproxy data on reconstruction quality.
Contents
Reconstructing past climate from noisy data ……………………………………………………….4-12
von Storch et al.
Comment on “Hockey sticks, principal components, and spurious significance” ………………….13-15 by S. McIntyre and R. McKitrick
von Storch and Zorita
Deep soil temperature as proxy for surface air-temperature in a coupled model simulation………..15-18
of the last thousand years.
González-Rouco et al.
Simulation and inversion of borehole temperature profiles in surrogate climates: Spatial …………..19-22
distribution and surface coupling
González-Rouco et al.
The Real Color of Climate Change …………………………………………………………………...23-24
Osborn and Briffa
Climate reconstruction by regression - 32 variations on a theme …………………………………….25-33
Bürger et al.
Are multiproxy climate reconstructions robust? ………………………………………………………34-37
Bürger and Cubasch
Representing simulations by reconstructions …………………………………………………………38-41
Bürger
Testing the reconstruction of Luterbacher et al. (2004) in the surrogate climate……………………..42-43
of ECHO-G and HadCM3
Küttel et al.
Test of the Mediterranean drough fluctuation reconstruction (summer PDSI)……………………….44-48
based on tree-ring data
Guiot et al.
References
Bürger, G., and U. Cubasch, 2005. Are multiproxy climate reconstructions robust? Geophys. Res. Lett., 32, L23711, doi: 10.1029/2005GL024155.
Bürger, G., I. Fast, and U. Cubasch, 2006. Climate reconstruction by regression - 32 variations on a theme. Tellus, in press.
González-Rouco, F., H. von Storch, and E. Zorita, 2003. Deep soil temperature as a proxy for surface air-temperature in a coupled model simulation of the last thousand years. Geophys. Res. Lett., 30, 2116, doi: 10.1029/GL018264.
Gonzalez-Rouco,F. , H. Beltrami, E. Zorita, H. von Storch, 2006.[Author ID1: at Mon Jan 30 10:12:00 2006
].[Author ID1: at Mon Jan 30 10:12:00 2006
][Author ID2: at Mon Jan 30 13:25:00 2006
] [Author ID1: at Mon Jan 30 10:12:00 2006
]Simulation and inversion of borehole temperature profiles in simulated climates: Spatial distribution and surface coupling.[Author ID1: at Mon Jan 30 10:12:00 2006
] [Author ID1: at Mon Jan 30 10:12:00 2006
]Geophys. Res. Lett[Author ID1: at Mon Jan 30 10:12:00 2006
]. [Author ID1: at Mon Jan 30 10:12:00 2006
]33[Author ID1: at Mon Jan 30 10:12:00 2006
], L01703.[Author ID1: at Mon Jan 30 10:12:00 2006
]
Luterbacher, J., D. Dietrich, E. Xoplaki, M. Grosjean, and H. Wanner, 2004: European seasonal and annual temperature variability, trends and extremes since 1500, Science, 303, 1499-1503.
Mann, M.E., [Author ID2: at Mon Jan 30 13:26:00 2006 ]and S. [Author ID2: at Mon Jan 30 13:27:00 2006 ]Rutherford, [Author ID2: at Mon Jan 30 13:26:00 2006 ]200[Author ID2: at Mon Jan 30 13:27:00 2006 ]2:[Author ID2: at Mon Jan 30 13:27:00 2006 ] Climate Reconstruction Using 'Pseudoproxies', Geophysical Research Letters, 29 (10), 1501, doi: 10.1029/2001GL014554.[Author ID2: at Mon Jan 30 13:26:00 2006 ][Author ID2: at Mon Jan 30 13:25:00 2006 ]
Mann, M. E., R. S. Bradley, and M. K. Hughes, 1999: Northern Hemisphere temperatures during the past millenniu: Infrences, uncertainties, and limitations. Geophys. Res. Lett., 26, 759-762.
McIntyre, M., and R. McKitrick, 2005: Hockey sticks, principal components and spurious significance. Geophys. Res. Lett., 32, L03710, doi: 10.1029/2004GL021750.
Nicault, A., S. Alleaume, S. Brewer, and J. Guiot, in prep. Mediterranean drought fluctuations during the last 650 years based on tree-ring data.
Osborn, T. J., and K. R. Briffa, 2004. The Real Color of Climate Change, Science, 306, 621-622.
Rutherford, S., M.E. Mann[Author ID1: at Mon Jan 30 10:07:00 2006 ], T.J. Osborb, R.S. Bradley, K.R. Briffa, M.K. Hughes and P.D. Jones, 2005. Proxy-bas[Author ID1: at Mon Jan 30 10:08:00 2006 ]ed Northern Hemisphere surface temperature reconstructions: sensitivity to method, predictor network, targ[Author ID1: at Mon Jan 30 10:09:00 2006 ]et season and target domain, [Author ID1: at Mon Jan 30 10:10:00 2006 ]J. Climate[Author ID1: at Mon Jan 30 10:10:00 2006 ], [Author ID1: at Mon Jan 30 10:10:00 2006 ]18[Author ID1: at Mon Jan 30 10:10:00 2006 ], 2308-2329.[Author ID1: at Mon Jan 30 10:10:00 2006 ]
Storch, H. von. and E. Zorita, 2005: Comment on `Hockey sticks, principal components, and spurious significance` by S. McIntyre and R. McKitrick. Geophys. Res. Lett., 32, L2071, doi: 10.1029/2005GLO22753.
Storch, H. von, E. Zorita, J. M. Jones, Y. Dmitriev and S. F. B. Tett, 2004. Reconstructing past climate from noisy data. Science, 306, 679-682.[Author ID2: at Mon Jan 30 13:29:00 2006 ][Author ID2: at Mon Jan 30 13:29:00 2006 ]
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