Atmospheric circulation patterns associated with strong wind events in Catalonia

Abstract

Abstract. The benefit of having a daily synoptic weather type catalogue and even more, a detailed catalogue for high impact weather events is well recognised by both climatologist and meteorologist communities. In this way the Meteorological Service of Catalonia (SMC) has produced some accurate classifications for extreme events, such as hailstorms or strong winds (SW). Within the framework of the MEDEX project, the SMC has been collaborating to increase the level of awareness about these events. Following this line of work, the aim of this study is to characterise the SW events in Catalonia.According to the guidelines of the MEDEX project we worked with its SW event database for the period June 1995 to May 2004. We also used the period 2005-2009 to test the methodology. The methodology is based on principal component, cluster and discriminant analyses and applied to four variables: SLP, temperature at 850 hPa and geopotential at 500 hPa on a synoptic-scale and local gust wind. We worked with ERA-Interim reanalysis and applied discriminant analysis to test the quality of the methodology and to classify the events of the validation period.We found seven patterns for the SW events. The strongest event corresponds to NW-Flow with the Azores Anticyclone and the passing of a low pressure through the Pyrenees. This methodology has distinguished the summer events in an independent cluster. The results obtained encourage us to follow this line of work.

Main features of large‐scale oceanic‐atmospheric circulation related to strongest droughts during rainy season in Brazilian São Francisco River Basin

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Key features of cold‐air pool episodes in the northeast of the Iberian Peninsula (Cerdanya, eastern Pyrenees)

“…Section 3 outlines the application of EOF analysis to detect the spatial and temporal occurrence of CAP (Lundquist et al, ). Synoptic situations associated with CAP and no‐CAP days are then characterized using a combination of principal component analysis (PCA), cluster analysis (CA) and discriminant analysis (DA) (Aran et al, ; Peña et al, ). Section 4 presents the results both spatially in terms of CAP distribution, and temporally in terms of appropriate synoptic conditions.…”

Daily near-surface large-scale atmospheric circulation patterns over the wider Caribbean

“…Even though a discrete number of atmospheric circulation types are unable to account for the full dynamics of the atmospheric continuum system, they have proved useful in understanding the regional and local climate variability of surface variables. Atmospheric circulation types in several regions globally have been linked to surface variables such as surface level ozone concentrations (Cooter et al 2007;Saavedra et al 2012), aerosol optical depths and concentrations of PM 10 (Zhang et al 2012), air temperature (Hoy et al 2013), cold spells (Guentchev and Winkler 2010), rainfall (Hope et al 2006;Raziei et al 2012;Romero et al 1999), flooding (Prudhomme and Genevier 2011), extreme surface winds (Peña et al 2011), and biological indicators such as potato yield (Sepp and Saue 2012). Our interest in the daily atmospheric circulation types (CTs) lies in extracting recurring daily types that could be used in future statistical-dynamical downscaling studies to develop high resolution wind climate maps at the mesoscale which are required to determine those areas that are best suited for wind farm development.…”