This work analyses the trend of annual precipitation in Aragon during the second half of the tentieth century, the spatial differences that this trend might entail in the Autonomous Community, both on an annual and a seasonal scale and the impact on water resources and their management. The regional series (1950-2000) presents drier and more humid phases and a slight negative trend which is not significant from the sixties onwards. The Zaragoza, Huesca and Teruel observatories follow a similar evolution. As regards to space, no significant trends can be observed in the annual totals of any Aragonese county; but instead on a seasonal scale there are some differences: winter shows a precipitation decreasing gradient from south-easat to north-west, opposite to the one produced in summer. Autumn has a clear north-south decreasing gradient, whereas spring does not offer clearly defined patterns. To be able to face the possible adverse effects coming from the rainfall decrease, efficient water policy actions are in need of a high degree of planning and rational water management.

Peer reviewed

17 páginas.