Extreme winter precipitation in the Iberian Peninsula in 2010: anomalies, driving mechanisms and future projections

Abstract

15 Pag., 3 Tabl., 10 Fig. ; This work provides a first assessment of the outstanding characteristics of the anomalous precipitation occurrence in the winter of 2010 over the Iberian Peninsula, as well as on the associated atmospheric driving mechanisms. Large areas of Iberia, those located in the western and southern sectors, registered a new historical maximum in winter precipitation values. Simultaneously, the most extreme, negative North Atlantic Oscillation (NAO) index for winter was recorded in 2010. The anomalous pressure gradient in the North Atlantic region steered a large number of low pressure systems via an unusually southern path, directly influencing Iberia and northern Africa. Storms were frequent, and a high number of days occurred with weather types prone to cause precipitation. In addition, the most extreme daily precipitation episodes were recorded during the period with the strongest negative NAO index. Global climate models for the entire 21st century show that strong negative NAO winters, similar to that which occurred in 2010, may be expected in the future. ; This work was supported by the research projects CGL2008-01189/BTE and CGL2006-11619/ HID, financed by the Spanish Commission of Science and Technology and FEDER; by EUROGEOSS (FP7-ENV-2008-1- 226487) and ACQWA (FP7-ENV-2007-1-212250), financed by the VII Framework Programme of the European Commission; and 'La nieve en el Pirineo aragonés: distribución espacial y su respuesta a las condiciones climáticas', financed by 'Obra Social La Caixa' and the Aragón Government. Ricardo Trigo's work was partially supported by the FCT (Portugal) through project ENAC (PTDC/AAC-CLI/103567/2008). ; Peer reviewed