Markovian behaviour of dry spells over the Iberian Peninsula using ESCENA regional climate models

NOELIA LOPEZ DE LA FRANCA; ENRIQUE SANCHEZ; MARTA DOMINGUEZ; TERESA LOSADA; RAQUEL ROMERA

Lund

Workshop; 3rd Lund Regional-scale Climate Modelling Workshop. 21st Century Challenges in Regional Climate Modelling; 2014

The dry spells over IB from the observational dataset present a second order markovian process characteristics. That is the occurrence of a dry day depends on the two preceding days had also been dry, implying persistence of the dryness.    A N-S decreasing gradient of the probability obtained in the SDSL is reversed in MDSL and LDSL. The North of IB is characterised by SDSL, while the South, especially the South East, by LDSL. A strong effect of the main orography over the markovian process of dry spells is shown, specially in the SDSL and LDSL.     The ESCENA RCMs reproduce successfully those observational spatial MC2 patterns. Thus, they can be used to analyse projected changes in the markovian future characteristics under different SRES.     A large agreement among the RCMs is obtained in climate change projections. The IB maintains present MC2 characteristics in the future except in just some points of the South East of IB. This fact can be due to great increases in the dry spell length. The SDSL project a N-S decrease of their probability of occurrence. In contrast, a increase of long lengths is showed over the domain, specially in the highest orographic points, except in the North West. MDSL exhibit some discrepancies between the simulations, while PROMES and MM5 display a general increase all over the domain, the rest project increases in the North and decreases in the South of IB.