The rainfall and erosivity database for Mexico (1968–2017)

Soil water erosion is the dominant soil degradation driver worldwide. Rainfall erosivity (also known as the R factor) quantifies the potential of rainfall to cause soil water erosion and is regarded as a dominant factor determining it. This contribution presents the first annual R factor database across the continental Mexico for three climate normals (1968–1997, 1978–2007, and 1988–2017). The workflow comprised three main steps. Firstly, a harmonaized daily rainfall time series dataset was obtained by compiling and harmonizing (through quality control, homogeneity analysis and gap-filling) 5410 raw rainfall time series distributed across Mexico. Secondly, three combinations of the α and β coefficients in a power model were tested to estimate daily R factors using three validation databases at global, national, and local scales. Thirdly, a validated and continuously distributed annual R factor for all three climate normal was obtained. Thus, the database presented herein encompasses 1369 (climate normal 1968–1997), 1678 (climate normal 1978–2007), and 1676 (climate normal 1988–2017) rainfall time series and the corresponding R factor. Our results indicate that the median values of the R factor for the three climate normals were 3245; 3070; and 3327 MJ mm ha⁻¹ h⁻¹ yr⁻¹, respectively. The statistical distribution of the R factor is right-skewed for the three climate normals, with high erosivity values reaching >12000 MJ mm ha⁻¹ h⁻¹ yr⁻¹ in all cases. The R factor across Mexico showed a strong ecoregional differentiation, with the highest values concentrated in the Tropical Rain Forest and Tropical Dry Forest ecoregions, whereas the North American Deserts and Mediterranean California exhibited the lowest values. The annual behavior of the R factor was similar for the three climate normals. However, September had the highest contribution to the annual R factor. By identifying areas with higher susceptibility to soil loss due to rainfall action and providing spatially distributed and well-documented estimates, we believe that the present R factor database has the potential to support the study of soil water erosion in the continental Mexico at country scale. Said database is available from a scholarly-accepted repository at https://doi.org/10.6073/pasta/dd2b30e28ee25ff2d60d8a9f436951d2 for public consultation.