Upscaling European surface temperatures to North Atlantic circulation‐pattern statistics

• Published in: International Journal of Climatology
• Main Authors: Orlowsky, B., Fraedrich, K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2008
• Subjects: North Atlantic
• Online Access: https://doi.org/10.1002/joc.1744; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjoc.1744; https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.1744

Abstract This paper examines reversal of the common downscaling path from large‐scale circulation patterns to local surface weather: Can changes of near‐surface temperature be used to predict changes in circulation‐pattern statistics? A re‐sampling (RS) scheme is applied, which generates ensembles of future series by assembling segments from past (or training) time series. The RS scheme is only constrained by known linear regression parameters of future annual mean temperatures. As circulation patterns, represented by the generalized patterns obtained by a cluster analysis, are part of the past series, the RS scheme also provides future time series of these patterns, conditioned only on the prescribed temperature evolution. In order to test whether changing statistics of temperature and circulation patterns are related to one another, a cross‐validation experiment using global circulation model (GCM) data is conducted: Two independent 30‐year periods are extracted from an Intergovernmental Panel on Climate Change (IPCC)‐simulation (ECHAM5), the first of which serves as a training sample (2001–2030) for the RS scheme to simulate the temperature regime of the second (2071–2100). The estimates by the RS scheme and the GCM simulation for the second period are analysed with respect to circulation‐pattern statistics. It is found that much of the changes from the first to the second period can be attributed to the temperature evolution. Future applications are discussed in the conclusions. Copyright © 2008 Royal Meteorological Society