A regional climate palaeosimulation for Europe in the period 1501–1990 – Part II: Comparison with gridded reconstructions
AbstractThis study jointly analyses gridded European winter and summer surface air temperature (SAT) and precipitation reconstructions and a regional climate simulation over the period 1501–1990. The European area is analysed separately for nine sub-areas. In their spatial structure, an overall good agreement is found between the reconstructed and simulated climate variability across different areas of Europe, supporting a consistency of both products and the proper calibration of the reconstructions. Still, systematic biases appear between both datasets that can be explained by a priori known deficiencies in the simulation. However, simulations and reconstructions largely differ in their estimates of the temporal evolution of past climate for European sub-regions. In particular, the simulated anomalies during the Maunder and Dalton minima show stronger response to changes in the external forcings than recorded in the reconstructions. This disagreement is to some extent expected given the prominent role of internal variability in the evolution of regional temperature and precipitation. However, the inability of the model to reproduce a warm period similar to that recorded around 1740 in winter reconstructions is indicative of fundamental limitations in the simulation that preclude reproducing exceptionally anomalous conditions. Despite these limitations, the simulated climate is a physically consistent dataset, which can be used as a benchmark to analyse the consistency and limitations of gridded reconstructions of different variables. Comparison of the main variability modes of SAT and precipitation indicates that reconstructions present too simplistic character of (natural) variability modes, especially for precipitation. This can be explained through the linear statistical techniques used for reconstruction. The analysis of the co-variability among variables shows that the simulation captures reasonable well the canonical co-variability, whereas independent reconstructions show unrealistically low correlations. Thus, the analysis points to a lack of dynamic consistency that reduces the confidence for subcontinental European reconstructions.