Statistical Analysis of 50-Years Biogeochemical Model Simulations in the Aegean Sea

We perform a detailed statistical analysis of the results from 50-year physical-biogeochemical simulations in the Mediterranean Sea. The data are generated by the 3-D General Estuarine Transport Model - GETM for the hydrodynamic fields and by the Fasham biogechemical model for nutrients and chlorophyll. The coupled model is forced with ECMWF atmospheric data, realistic bathymetry, river discharges and riverine nutrient inputs. The horizontal resolution of the model output is 5'x5' and the multiannual runs cover the period from 1960 to 2009. Specifically we examine here several sub-domains within the Aegean Sea that differ in the forcing and in the nutrient inputs. We use sea-surface temperatures and chlorophyll-a distributions derived from satellite observations for comparison to the physical-biogeochemical model results. The data are analyzed with respect to autocorrelation, linear trends, non-linear functional forms and the occurrence of breakpoints in the time series. The applied statistical methods always comprise significance tests and confidence limits for the investigated characteristics. It was not possible to identify a clear regime shift in the Aegean Sea, at least not at the by Conversi et al. (2010), proposed date for a Mediterranean regime shift at the end of the 1980s. This must not be a contradiction, as nearly all the parameters considered in Conversi et al. (2010) are from the Western Mediterranean and Adriatic Sea and not from the Aegean Sea. Therefore it might be that the Aegean Sea has an own different dynamics than the whole Mediterranean Sea. We cannot confirm the speculated regime shift in SST at about 1998 of Raitsos et al. (2010), when applying our statistical testing methods.

STIPS Adolf;  GARCIA GORRIZ Elisa;  LESSIN Gennadi; 

2011-12-01

Mediterranean Coastal Foundation (MEDCOAST Foundation)

JRC66547

https://publications.jrc.ec.europa.eu/repository/handle/JRC66547,