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Description of mean fields and interannual variability in an ensemble of RCM evaluation simulations over Spain: results from the ESCENA project

Journal: Climate Research
Year: 2013   Volume: 57
Initial page: 201   Last page: 220
Status: Published
In this status since: 25 Apr 2013
Link to PDF: PDF article
DOI: 10.3354/cr01165
P. Jiménez-Guerrero, J. P. Montávez, M. Domínguez, R. Romera, , , W. D. Cabos, G. Liguori, and M. A. Gaertner

The ESCENA (2008-2012) project is a Spanish initiative which applies the dynamical downscaling technique to generate climate change scenarios based on an ensemble of Regional Climate Models (RCMs such as PROMES, WRF, MM5 or REMO) over Peninsular Spain and the Balearic and Canary Islands using a high resolution of 25 km. The mean fields and interannual variability for temperature and precipitation in an ensemble of simulations forced by the high resolution ERA-Interim reanalysis have been described. The results for these variables and indices from the ERA-Interim-forced simulations (1990-2007) are compared to the Spain02 observed data set. This database was developed following the ENSEMBLES E-OBS database methodology but using a much larger amount of daily station data. Thus, it is very suitable over the Iberian Peninsula to be compared with high resolution RCMs.

Maximum surface air temperature shows seasonal cold biases in all models up to -2.5 K, with relatively clear signal that the modeled maximum temperature is clearly underestimated during the coldest seasons, while these biases reduce during summertime (JJA). Generally, there is a better agreement between observed and simulated minimum surface air temperature, which is slightly overestimated (up to +2K) in the simulations especially during wintertime (DJF). Regarding precipitation, the models tend to show low dry biases during all seasons (but PROMES), especially for autumn in the Mediterranean coast of the Iberian Peninsula. With respect to the interannual variability, the PROMES simulations overestimate the standard deviation of maximum surface air temperature when compared against the Spain02 data, particularly during JJA (+0.3K); while the rest of models tend to slightly underestimate the interannual variability. For precipitation, most models tend to underestimate the Spain02 standard deviation. In DJF and SON, the differences in the interannual variability are the highest between models both for temperature and precipitation. The results point out the ability of these RCMs to reproduce the mean fields and the interannual variability in a very complex terrain such as the Iberian Peninsula, showing a great diversity of climatic behavior. However, the evaluation of the ensemble results indicates a great improvement in the temporal correlation and the representation of the spatial patterns of temperatures and precipitation with respect to the individual models for all seasons. Hence, the use of ensemble simulations in this kind of regional climate studies improves the representativity of the climatologies and provide valuable estimation of the associated uncertainty.