Diaz, H. F., 1996: Temperature changes on long time and large spatial scales: Inferences from instrumental and proxy records. In Climatic Variations and Forcing Mechanisms of the Last 2000 Years, P. D. Jones, R. S. Bradley, and J. Jouzel (Eds.), Springer-Verlag, 585-601.
The capability of various sets of individual and regional surface temperature indices to represent hemispheric- to global-scale averages on decadal to century timescales is evaluated. It is shown that on time scales ranging from intraseasonal to decadal, the principal modes of temperature variability in the atmosphere at the surface and in the lower troposphere are consistently of very large spatial extent. Analyses of the sea surface temperature field also indicates the presence of large spatial modes on interannual to decadal timescales. It is suggested that temperature signals at longer timescales, e.g., periods of the order 10-100 years, may be reproducible, at least in broad outline, from a relatively small suite of high-resolution, high-quality paleotemperature records, which are themselves sensitive to climatic fluctuations at long temporal and large spatial scales.