Intercomparison of gridded products: a multidimensional perspective

Abstract

Observational uncertainty has become an increasingly significant concern in climate studies. In this context, mainland Spain has several publicly available daily gridded datasets of precipitation, which have been utilized in various regional and national studies. Recent research, like the latest CLIVAR-Spain report, underscores the need for thorough intercomparison among these datasets, highlighting their respective strengths and limitations while discussing findings in light of existing observational uncertainties. This study seeks to address this issue by performing a comprehensive analysis of 10 gridded datasets of daily precipitation currently available for mainland Spain. It is the first study to conduct an extensive comparison across these datasets, focusing on multiple dimensions: statistical distribution, extreme events and spells. Our findings indicate that national datasets are more similar to each other than to global or European-wide datasets. While mean values primarily differ in intensity, these differences extend to spatial patterns when extremes or spells are considered, thereby expanding or reducing the affected regions. These variations remain mostly consistent with altitude, with most datasets exhibiting similar behavior, except for EOBS v27e, EMO-1arcmin, and ERA-Land.