How Reliable are Climate Models in Term of Regional Sea Level ?

Abstract:

The sea level fluctuations result from complex interactions between diverse physical processes and, as many other geophysical signals, exhibit long-term correlations that can be modeled as outcomes of stochastic power-law process with a Hurst exponent, a > 0.5. The spatial variations in the magnitude of the Hurst exponent in the observed sea level tide gauge records seem to follow regular patterns that is potentially important for understanding sea level changes and for developing an adequate noise model required by an accurate sea level trend estimation. Here, we address the key question: Do the climate models reproduce the universal power law behavior observed in tide gauge sea level records? We compare the spatial distribution of the Hurst exponents derived from tide gauge observations with those predicted by 36 Atmosphere–Ocean General Circulation Models (AOGCMs), contributing to the fifth phase of the Coupled Model Intercomparison Project (CMIP5), and discuss the possible links between the scaling and the main features of the global ocean-atmosphere circulation.