Bioclimatic drought tren study through the application of the ombroxeric index. A case study: the province of León (Spain)

The ombroxeric index (OXI), a drought-indicative bioclimatic index based on the Rivas-MartínezWorldwide Bioclimatic Classification System (WBCS), was used in this work to establish theombroxericity trends in a defined study area: the province of Leon (Spain). On the basis oflarge time-scale climatological gridded databases (MOPREDAS and MOTEDAS), with datafrom 1951 to 2010 at monthly, seasonal an annual study level, a Mann-Kendall test-basedtrend analysis was carried out and a geostatistical interpolation procedure, EmpiricalBayesian Kriging (EBK), was applied. Statistically significant increases were revealed in themonths of March and June, as well as in the summer period. These increments are greaterin the southernmost areas and could be related with changes in some teleconnectionpatterns. With this up-to-date approach, besides being aware of the direct bioclimate-altering consequences of the climate change, the prediction of the implications in thevegetation is made possible, due to the typological-predictive character of the model ofclimate-vegetation reciprocity provided by the WBCS.