Spatial and temporal evolution of droughts in the middle Ebro Valley: Causes and environmental consequences (Spanish text, Spain).

摘要

The desertificacion, the climatic change, the contamination and the biodiversity lost are the main environmental problems of the Twenty-one century. The drought always appears as cause or direct consequence related to these problems.; The problems that droughts generate are more important in arid and semi-arid regions because in these areas the water is a scarce resource with a high temporal uncertainty.; Due to the great interest of droughts in Aragon (North East of Spain), and also due to their negative consequences, it is necessary to know this climatic phenomenon in more depth since its implications are very complex.; In this work droughts have been analysed in the central regions of Aragon temporally and spatially, and considering different topics: (1) The knowledge of the temporal evolution of droughts, their spatial patterns and the recent trends in the behaviour of this phenomenon. (2) The analysis of the atmospheric causes of droughts considering the synoptic spatial scale and the general continental and hemispherical circulation. (3) The map of drought hazard using stochastic methods. (4) The analysis of drought consequences on natural vegetation and crops by means of remote sensing. (5) The drought impacts on crop productions. (6) The usefulness of early warning tools to facilitate the mitigation of droughts.