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New Euro-CORDEX Compliant Gridded Observational Datasets in Spain: Assessing the Effect of the Interpolation Methodology in the Mean and Extreme Precipitation Regimes

Conference: International Conference on Regional Climate - CORDEX 2013
Year: 2013
Contribution type: Poster
Poster: 2013_CORDEX_Poster_Herrera.pdf

A few gridded products based on observations are available covering a wide range of spatial scales (global, continental, national or regional). These products are commonly used to evaluate the performance of regional climate models. However, the limited access to different datasets in a given region have prevented an in-depth study of the observational uncertainty due to the different station networks, interpolation methods or resolutions used to build these data sets.

In this study we present a new set of daily precipitation gridded datasets developed for peninsular Spain and the Balearic islands using a dense network of quality-controlled stations. These datasets comprise different standard interpolation methodologies (ordinary kriging, thin plate splines, etc.) and two horizontal resolutions, 0.11º and 0.44º, exactly matching the rotated grids defined in the framework of Euro-CORDEX. Moreover, two different approaches have been followed in order to guarantee areal-averaged or point representativity of the resulting grid values. For the former, the interpolation process has been carried out in two steps, following the approach used to build E-OBS: 1) the interpolation method has been applied at a 0.01º horizontal resolution and 2) the final grids have been obtained averaging the results into the final resolution. Furthermore, two alternative approaches are considered in all cases to test the sensitivity to the use of the orography as a covariable in the interpolation procedure.

Besides of introducing the new set of gridded datasets, in this work we also present some preliminary results on the sensitivity of the mean and extreme regimes of precipitation to all these factors. In the former case we analyze the effect on the mean and variability, whereas in the latter, we analyze the impact on different return values.

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