Advances in Geosciences www.adv-geosci.net 1680-7340 1680-7359 26 11th EGU Plinius Conference on Mediterranean Storms (2009) 2010 10.5194/adgeo-26-61-2010 http://www.adv-geosci.net/26/61/2010/ http://www.adv-geosci.net/26/61/2010/adgeo-26-61-2010.html http://www.adv-geosci.net/26/61/2010/adgeo-26-61-2010.pdf 61 64 2010-07-09 The effect of observation timescales on the characterisation of extreme Mediterranean precipitation A. M. Camarasa Belmonte J. Soriano García M. J. López-García Department of Geography, University of Valencia Avda. Blasco Ibáñez, 28, 46010 Valencia, Spain This paper analyses the behaviour of five rainfall indicators (maximum intensity, cumulative rainfall, irregularity, probability of rain and persistence of rain) over different observation timescales ranging from 5 min to 24 h. It covers a large area on the Mediterranean side of the Iberian Peninsula (River Júcar Water Authority, 43 000 km²) on a continuous basis over a period of 14 years (1994–2007). The results show that the behaviour of extreme Mediterranean rainfall is heavily dependent on the observation timescale. There are a number of turning points in the indicator trends which occur on different timescales (1 and 6 h in the case of rain intensity and irregularity, 6 h for cumulative rainfall and between 15 and 30 min for the persistence of rain) and may be relevant for the determination of thresholds used in water management. Beguería, S., Vicente-Serrano, S., López-Moreno, J. I., and García-Ruíz, J. M.: Annual and seasonal mapping of peak intensity, magnitude and duration of extreme precipitation events across a climatic gradient, northeast Spain, Int. J. Climatol. 29, 1759-1779, 2009. Bull, L. J., Kirkby, M. J., Shannon, J., and Hooke, J. M.: The impact of rainstorms on floods in ephemeral channels in southeast Spain, Catena, 38, 191–209, 1999. Camarasa, A. M.: La intensitat de la precipitació, in: Atlas climàtic de la Comunitat Valenciana, C.O.P.U.T., edited by: Pérez Cueva, A., València, Spain, 100–101, 1994. Camarasa, A. M. and Segura, F.: Flood events in Mediterranean ephemeral streams (ramblas) in Valencia region, Spain, Catena, 45, 229–249, 2001. Camarasa, A. M. and Tilford, K. A.: Rainfall-runoff modelling of ephemeral streams in the Valencia region (Eastern Spain), Hydrol. Proc., 16(17), 3329–3344, 2002. Cammeraat, E.: Scale dependent thresholds in hydrological and erosion response of a semi-arid catchment in southeast Spain, Agr. Ecosyst. Environ., 104, 317–332, 2004. Cudennec, C., Leduc, C., and Koutsoyiannis, D.: Dryland hydrology in Mediterranean regions – a review, Hydrol. Sci. J., 52(6), 1077–1087, 2007. Dunkerley, D.: Identifying individual rain events from pluviograph records: a review with analysis of data from an Australian dryland site, Hydrol. Proc., 22, 5024–5036, 2008. Gil Olcina, A.: Causas climáticas de las riadas. Avenidas fluviales e inundaciones en la cuenca del mediterráneo. Instituto Universitario de Geografía de la Universidad de Alicante y Caja de Ahorros del Mediterráneo, 15–30, 1989. Jebari, S.; Berndtsson, R. Uvo, C. and Bahri, A. (2007): Regionalizing fine time-scale rainfall affected by tophography in semi-arid Tunisia. Hydrological Sciences Journal, 52, 1199-1215. Kokkonen, T., Koivusalo, H., Karvonen, T., Croke, B., and Jakeman, A.: Exploring streamflow response to effective rainfall across event magnitude scale, Hydrol. Process., 18, 1467–1486, 2004. Llasat, M. C.: An objetive classificationof rainfall events on the basis of their convective features: application to rainfall intensity in the northeast of Spain, Int. J. Climatol., 21, 1385–1400, 2001. Martín-Vide, J.: Spatial distribution of a daily Precipitation Concentration Index in Peninsular Spain, Int. J. Climatol, 24, 959–971, 2004. Peñarrocha, D., Estrela, M. J., and Millán, M.: Classification of daily rainfall patterns in a Mediterranean area with extreme intensity levels: the Valencia region, Int. J. Climatol, 22, 677–695, 2002. Romero, R., Ramis, C., and Guijarro, J. A.: Daily rainfall patterns in the Spanish Mediterranean area: an objective classification, Int. J. Climatol, 19, 95–112, 1999. Waymire, E. and Gupta, V. K.: The mathematical structure of rainfall representations 1. A review of the stochastic rainfall models, Water. Resour. Reser. 17 (5), 1261–1272, 1981. Yair, A. and Lavee, H.: Runoff generation in arid and semi-arid zones, edited by: Anderson, M. G. and Burt, T. P., Hydrol. Forecast., 1, 183–220, 1985.