Analysis of the precipitation and cloudiness associated with COLs occurrence in the Iberian Peninsula

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The Iberian Peninsula is one of the regions in the world with higher occurrence of cut-off low systems (COL). The aim of this paper is to analyse the weather events (rainfall and cloudiness layer) associated to COLs in the Iberian Peninsula with tools not previously used: (a) the use of the new multidecadal COLs database developed by Nieto et al (2005) that permit us to study a 41 years period (1958-1998), (b) the checking of the expected weather events (rainfall and cloudiness layer) associated with COLs in a conceptual model (Winkler et al, 2005) and (c) the extensive use of radiosoundings to analyse convective instability in areas inside and close to the COL. Two points of view are used to make the analysis: (1) a source oriented method, when a particular COL is followed and its associated precipitation and cloudiness is analysed over four quadrants in which Iberia was divided and (2) a receptor oriented method, when the precipitation associated to COLs is analysed in given areas, defined by patterns of precipitation. Results reveal that the precipitation and cloudiness patterns associated to COLs in the conceptual model reproduce quite well the main characteristics found over the Iberian Peninsula. The generalized idea that most of the COLs produce intense convective rainfall is show to be misleading. Convective phenomena are important usually when the centre of the COL is located on the Mediterranean region. Most of the rainfall associated with COLs comes from the baroclinic shield; specially in cases located over the west half of the Iberian Peninsula. It is shown that nearly 30% of COLs do not induce any rainfall; most of them located in the southern half of the Peninsula, and mainly during autumn. Only 30% of COLs produce generalized rainfall over the whole analysed territory, being most of them (about 90%) located over the western half of the Iberian Peninsula.
© Springer-Verlag 2006. This work was supported by the Spanish Ministry of Science and Technology (MCYT) under Grant REN2002-04558-C04- 01=02=03=04 and by the Galician Programme of Research and Development under Grant GIDIT03PXIC38301PN. This work was supported also by a postdoctoral fee (SFRH= BPD=22178=2005) to the principal author from the FCT of Portuguese Ministry of Science, Technology and Education. The authors wish to thank the Spanish National Meteorology Institute (INM) for providing the data analysed in this study.
Durre I, Russel SV, Wuertz DB (2006) Overview of the Integrated Global Radiosonde Archive. J Climate 49: 53–68 Esteban Parra MJ, Rodrigo FS, Castro Díez Y (1998) Spatial and temporal patterns of precipitation in Spain for the period 1880–1992. Int J Climatol 18: 1557–1574 Gallego MC (2004) Un estudio de la variabilidad climática en la Península Ibérica. PhD Thesis, Universidad de Extremadura, 328 pp Gallego MC, García JA, Vaquero JM (2005) Distribución espacial de índices de frecuencia de precipitación diaria en la Península Ibérica. Física de la Tierra 16: 161–174 García R, Gallego D, Hernández E, Gimeno L, Ribera P (2001) Influence of the North Atlantic Oscillation on the Canary Islands precipitation. J Climate 14(19): 3889–3903 Hoskins BJ, McIntyre ME, Robertson AW (1985) On the use and significance of isentropic potential vorticity maps. Q J Roy Meteor Soc 111: 877–946 [see, Corrigendum (1987) 113: 402–404] Jansá A (2004) „Qué es la gota fría? Ambienta 36: 59–62 Knippertz P, Martin JE (2005) Tropical plumes and extreme precipitation in subtropical and tropical West Africa. Q J Roy Meteor Soc (in press) Kurz M (1998) Synoptic meteorlogy. Deutscher Wetterdienst Offenbach am Main, 200 pp Llasat MC(1987) Episodios de lluvias copiosas en Cataluña: génesis, evolución y factores coadyuvantes. PhD Thesis, Universidad de Barcelona, Barcelona, 543 pp Llasat MC, Puigcerver M (1987) Gotas de aire frío. Revista de Geofísica 42: 245–246 (in Spanish) Llasat MC, Puigcerver M (1989) Gotas de aire frío en la Península Ibérica: Características. Revista de Geofísica 45: 177–188 (in Spanish) Llasat MC, PuigcerverM(1990) Cold air pools over Europe. Meteorol Atmos Phys 42: 171–177 Llasat MC, Martín F, Barrera A (2005) From the concept of ‘‘Kaltluftropfen’’ (cold air pool) to the cut-off low. The case of September 1971 in Spain as an example of their role in heavy rainfalls. Meteorol Atmos Phys (this issue) Martín León F (2003) Las gotas frías/DANAs, ideas y conceptos básicos. Nota técnica del Servicio de Técnicas de Análisis y Predicción (STAP), no 38, 14 pp. Instituto Nacional de Meteorología. Ministerio de Medio Ambiente, Madrid (in Spanish) Muñoz Díaz D, Rodrigo FS (2004a) Impacts of North Atlantic Oscillation on the probability of dry and wet winters in Spain. Climate Res 27: 33–43 Muñoz Díaz D, Rodrigo FS (2004b) Spatio-temporal patterns of seasonal rainfall in Spain (1912–2000) using cluster and principal component analysis: comparison. Ann Geophys 22: 1435–1448 Nieto R, Gimeno L, de la Torre L, Ribera P, Gallego D, García Herrera R, García JA, Nuñez M, Redaño A, Lorente J (2005) Climatological features of cut-off low systems in the Northern Hemisphere. J Climate 18, No 16: 3085–3103 Nieto R, Gimeno L, de la Torre L, Ribera P, Barriopedro D, García Herrera R, Serrano A, Gordillo A, Redaño A, Lorente J (2006) Interannual variability of cut-off low systems over the European sector: the role of blocking and the Northern Hemisphere Circulation Modes. Meteorol Atmos Phys (this issue) Palmen E, Newton CW (1969) Atmospheric circulation systems. New York London: Academic Press, pp 273–285 Rodríguez Puebla C, Encinas AH, Nieto S, Garmendia J (1998) Spatial and temporal patterns of annual precipitation variability over the Iberian Peninsula. Int J Climatol 18: 299–316 Serrano A, García JA, Mateos VL, Cancillo ML, Garrido J (1999) Monthly modes of variation of precipitation over the Iberian Peninsula. J Climate 12: 2894–2919 Winkler R et al (2005) Manual of synoptic satellite meteorology. Conceptual models, Vers. 6.0. (Available at Central Institute for Meteorology and Geodynamics, Hohe Warte 38, 1190 Vienna, Austria)