Science et changements planétaires / Sécheresse


Analyse par la chaîne de Markov de la sécheresse dans le sud-est de l’Espagne Volume 4, issue 2, Juin 1993

Université de Murcia, Campus de la Merced, 30001 Murcia, Espagne, Université de Barcelone, 08028 Barcelone, Espagne.
  • Page(s) : 123-9
  • Published in: 1993

The south-eastern regions of Spain, from Catalunya to Andalusia, undergo frequent, and ofter long, periods of no rain, especially in the summer. To try and forecast the occurence and duration of these - and this would be a great help in water-resource management and agricultural decision-making - the validity of statistical calculation based on 1st-, 2nd-, 3rd- order Markov chains was tested. After a demonstration of applying this method to past phenomena of drought covering the period 1941 to 1970, the paper concludes that results calculated using a Markov chain, despire their complexity, were not noticeably better thant those achieved by farmers with their own empirical methods. The mediocre results were attributed to not separating summer droughts from winter droughts, leading, in statistical terms, to two populations of very different characteristics being aggregated.