One main focus involves the reconstruction of climate, based on observational, model and proxy data. The statistical analysis provides furthermore a synthesis, comparison and interpretation of paleo and simulated data. Climate reconstructions will be built by geostatistics, which is based on spatial correlations or composite maps. The combined use of paleoclimate reconstructions and model-simulated climate data will be undertaken, bringing together expertise and data from the paleoclimate and the climate modeling communities.

The comparison of paleo and model data can be carried out in a number of ways. The simplest approach is to subsample the model output fields, picking out data only from these locations and seasons for which the paleo reconstructions exist (Jones et al., 1998). Modeled signal-to noise-ratios may be used to evaluate locations where climate phenomena can be detected. Comparison can also be made with different simulations, in order to assess whether the additional forcings raise the levels of multi-decadal to centennial variability to a similar extent in both the simulated and reconstructed climates. Using the model work and instrumental data, teleconnections and their role for long-term climate variability are investigated. Model results are compared with recent reconstructions of the temperature record of the last millennium (Mann et al., 1999).

In addition to the paleo evidence being used to evaluate model performance, the model simulations will aid in the interpretation of the paleo data. The climate simulations enable a separation of the externally-forced climate signal from internal variability (to the extent that the signal is distinguishable from the noise), something that cannot be achieved using paleo data alone. The model signals will be used to interpret the paleoclimate reconstructions, in terms of the causes of the observed variations.

In order to get a physically consistent picture of the underlying large-scale processes, the statistical analysis is of central importance for paleoclimate research proposed in my concept. Typical circulation patterns are evaluated with the help of instrumental and historical data (e.g., Appenzeller et al., 1999; Rimbu et al., 2001 - pdf 292 KB). Historical and reanalysis data sets are used to find the associated atmospheric circulation and sea surface temperature patterns. One objective of such studies is to understand the teleconnections that control the low frequency variations in the proxy records.

In the ideal case, the method provides for a reconstruction of climate modes beyond the instrumental record. It can also bring climate shifts, such as that observed in the 1970s, into a long-term context. The proxy data can provide estimates of natural climate variability in the pre-industrial era. This seems to be very important in terms of detection of the anthropogenic influence on climate change.