Dynamical Downscaling of surface wind circulations in the Northeast of the Iberian Peninsula Pedro A. Jiménez (UCM-CIEMAT) J. Fidel González-Rouco (UCM) Juan P. Montávez (UM) Elena García-Bustamante (UCM-CIEMAT) J. Navarro (CIEMAT)

1.- Regional VS local evaluation 2.- Wind variability: Regionalization Group together those observational sites with similar temporal variability 3.- Dynamical downscaling Evaluation Inference analysis Outline Motivation: - Analyze the surface wind variability in a complex terrain region - Evaluate the capability of a dynamical downscaling to reproduce it

1.- Regional VS local evaluation The present evaluation uses the Reid and Turner concept of regional evaluation to analyze the accuracy of a dynamical downscaling in reproducing the surface wind variability. The evaluation of numerical simulations usually compares observations and simulations at the nearest grid point Cox et al Hanna and Yang 2001 Buckley 2004 Reid and Turner 2001 Problematic: 1.- Local effects in observations 2.- Representativeness errors in simulations

Observational data Wind speed and wind direction From 1992 to minutes resolution 10 above ground level Quality control Ebro valley Pyrenees Cantabrian mountains Iberian System Daily averages

Ebro valley (Broad valley)‏ 2.- Regionalization Jimenez et al., JAMC; 47, 2008 Methodology: Rotation of the EOF Northern valleys (Narrow valleys)‏ Mountain stations North-to-south oriented stations

3.- Dynamical downscaling Initial and boundary conditions every 6 hours form the ERA-40 reanalysis WRF The whole observational period (1992 to 2005) is simulated at at high horizontal resolution of 2km over the area of study. Local VS Regional

Ebro valley (Broad valley)‏ Evaluation Jimenez et al., JAMC (submitted)‏

Observations Mountain subregion Regionalization obtained with the spatially masked simulation Evaluation: Regionalization in WRF Simulation Normalized spectral density

3.2.- Inference analysis: Regionalization obtained with the complete simulation

Conclusions 1.- The regional evaluation seems to provide a more appropriate framework than the traditional comparison with the nearest simulated grid point. 2.- The WRF dynamical downscaling is able to reproduce areas of coherent wind variability. 3.- The simulation can be extended to analyze the wind variability before 1992.

Canonical series 1 Corr.: 0.87 Statistical downscaling Canonical Correlation Analysis: optimal linear association between large scale circulation and local wind field Validation and methodology sensitivity zonal wind component Wind climatology reconstruction Kalnay et al., Bu. Amer. Met. Soc, 21; 1996 Kallberg et al., Rep. Seri. 17, ECMWF; 2004 Luterbacher et al., Cli. Dy., 18; 2002 Large scale data: Kalnay et al., Bu. Amer. Met. Soc, 21; 1996 Kallberg et al., Rep. Seri. 17, ECMWF; 2004 Luterbacher et al., Cli. Dy., 18; 2002

ERA-40 VS WRF