A classification of the atmospheric circulation patterns producing significant daily rainfall in the Spanish Mediterranean area

Romero, R.; Sumner, Graham; Ramis, C.; Genovés, A.

doi:10.1002/(sici)1097-0088(19990615)19:7<765::aid-joc388>3.0.co;2-t

Cited by 204 publications

(215 citation statements)

References 21 publications

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“…Automatic classifications are based on statistical techniques such as k-mean clustering (Matyasovszky et al, 1993), correlation (Yarnal, 1993), principal component analysis (PCA, Kutzbach, 1970;Deser and Blackmon, 1993;Wallace and Gutzler, 1981) or fuzzy rules (Pesti et al, 1996). Romero et al (1999) used a PCA in T-mode for weather-type classification in the Iberian Peninsula and, in the same region (Corte-Real et al (1998);Rasilla (2002) and Esteban et al (2005), used an algorithm that combines the k-mean clustering and the PCA for the same purpose.…”

Section: Analysis Of the Temporal Variability Of The Winter Atmosphermentioning

confidence: 99%

“…Nevertheless, the complex relief that characterises the Iberian Peninsula and the maritime influence can modulate these influences spatially. In the Mediterranean coastland, different authors have shown that flows from east, and cyclonic weather types have an important role in precipitation (Romero et al, 1999;Goodess and Jones, 2002). Moreover, the flows from east can be reactivated because of hot conditions in the sea-surface temperature, which is frequent in autumn and early winter (Martín-Vide and Llasat, 2000;Serra et al, 1996;Millán et al, 1995).…”

Section: Influence Of Weather-type Frequency On Drought Spatial and Tmentioning

confidence: 99%

“…For this reason, efforts have been dedicated to the development of classification methods based on different catalogues of weather types (Yarnal et al, 2001). The synoptic spatial scale has been widely used for regional precipitation modelling (Romero et al, 1999;Phillips and McGregor, 2001;Svensson et al, 2002;Santos et al, 2005). Moreover, in different regions, evidence has been provided about relationships between weather-type frequency and general atmospheric circulation patterns (Wilby, 1993;Fraedrich, 1994;McCabe and Muller, 2002;Stefanicki et al, 1998;Sheridan, 2003).…”

Section: Introductionmentioning

confidence: 99%

“…Different studies have analysed the influence of weather-type frequency on precipitation in different Mediterranean regions, mainly for intense precipitation events (Romero et al, 1999;Kahana et al, 2002Kahana et al, , 2004Esteban et al, 2005). Nevertheless, a few studies on the influence of the frequency and persistence of weather types on droughts in this region have been published (Delitala et al, 2000;Olcina, 2001;Brunetti et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

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The influence of atmospheric circulation at different spatial scales on winter drought variability through a semi‐arid climatic gradient in Northeast Spain

Vicente‐Serrano

López‐Moreno

2006

Intl Journal of Climatology

126

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This paper analyses the spatial and temporal variability of winter droughts in a semi-arid geographic gradient in Northeast Spain, from the Pyrenees in the north to the Mediterranean coastland in the south. Droughts that occurred between 1952 and 1999 were analysed by means of the Standardised Precipitation Index (SPI). The influence of the weather-type frequency and of the general North Atlantic atmospheric circulation patterns was analysed. The results indicate that winter droughts show an important spatial variability in the study area, differentiating three well-defined patterns. These correspond to the Pyrenees, the centre of the Ebro Valley, and the Mediterranean coastland. General negative trends in winter SPI have been found, which are indicative of the increase in winter drought conditions in the study area. Nevertheless, important spatial differences have also been recorded. Dominant north-south gradients in the influence of weather types are shown. Moreover, the negative trends in winter-SPI values agree with the negative trend in the frequency of the weather types prone to cause precipitation, such as the C, SW and W weather types and the increase in the frequency of A weather types. Nevertheless, in the Mediterranean coastland, the positive trend in SPI values agrees with the increase in the frequency of weather types of the east (E, SE), which are prone to cause precipitation in this area. Interannual variations in the frequency of the different weather types have been highly determined by different general atmospheric circulation patterns, mainly the North Atlantic Oscillation (NAO). Nevertheless, the correlation between the time series of weather-type frequency and the winter SPI is higher than that found between the SPI and the NAO. Thus, although the interannual NAO variability explains a high percentage of the interannual differences in the frequency of different weather types, it is not sufficient to explain the spatial and temporal variability of droughts, which respond better to atmospheric variability at more detailed (synoptic) spatial scales.

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Section: Analysis Of the Temporal Variability Of The Winter Atmosphermentioning

confidence: 99%

Section: Influence Of Weather-type Frequency On Drought Spatial and Tmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The influence of atmospheric circulation at different spatial scales on winter drought variability through a semi‐arid climatic gradient in Northeast Spain

Vicente‐Serrano

López‐Moreno

2006

Intl Journal of Climatology

126

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“…In this way, and to analyse precipitation variability in Portugal in relation to large-scale circulation, Corte-Real et al (1998) applied an information measure based on the precipitation series for determining the optimal number of groups for K-means, eliminating subjectivity in this step of the classification. With T-mode and correlation matrix in PCA, and K-means CL previously oriented by Ward's hierarchical method, Romero et al (1999a) identified 19 atmospheric circulation patterns at two levels (925 and 500 hPa) related to significant rainfall days for Mediterranean Spain. The patterns obtained have been related to the precipitation spatial patterns obtained by the same authors via PCA and CL techniques for the area treated (Romero et al, 1999b), and recently changes have been estimated in these precipitation patterns for the late twenty-first century using the GCM ECHAM-OPYC3 (Sumner et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Daily atmospheric circulation catalogue for western Europe using multivariate techniques

Esteban

Martín‐Vide

Mases³

2006

Intl Journal of Climatology

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This study uses principal component analysis (PCA) and clustering (CL) techniques to characterize the daily surface synoptic circulation patterns over the region 30°N-60°N by 30°W-15°E, for the period 1960-2001 using the NCEP/NCAR Reanalysis Project data. The methodology used, previously proposed by Esteban et al. (2005) to identify heavy snowfall days over Andorra (Pyrenees), involves a pre-processing approach consisting of a spatial standardization of the data used for the rotated PCA on S-mode analysis and correlation matrix, and Varimax rotation of the retained components. For the clustering process, an alternative approximation based on the PCA results (positive and negative phases) to decide the centroids and the number of groups for the K-means clustering is shown, followed by the rejection of the iterations for this non-hierarchical algorithm. Twenty sea level pressure (SLP) circulation patterns were obtained, with all days classified. The composite maps for SLP and 500 hPa geopotential height (GPH), the monthly distribution, and the long-term variability for each of the circulation patterns is obtained. The results are consistent with the subjective knowledge of the daily atmospheric circulation over the area treated, and seem to be an easy and accessible way for the synoptic studies of short-lived (from weekly to daily) phenomena. In addition, this methodology appears to be applicable to all climatic areas of the world, as it characterizes well enough the complex circulation variability at mid-latitudes, including the surface low-pressure gradient patterns normally located over the Mediterranean in summer.

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Weather Patterns and Weather Types

McKendry

2005

Encyclopedia of Hydrological Sciences

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In popular usage, the terms “weather pattern” and “weather type” are used variously and often imprecisely to describe states of the atmosphere. An understanding of weather processes and patterns has important applications in such diverse areas as air‐quality management, hydrology, water management, human health, forestry, agriculture, energy demand, transportation safety, the insurance industry, economics, and tourism. These terms are formally defined and the various classification techniques that form the basis of synoptic climatology are described. In summarizing the various methods used to identify weather patterns and types, it is abundantly clear that underlying such approaches are significant assumptions about the state of the atmosphere together with varying degrees of subjectivity inherent in the techniques themselves. It is important that these constraints are adequately acknowledged in all applications of the techniques outlined. Finally, the impacts of computing advances, new techniques, and enhanced datasets on synoptic climatology are described.

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A classification of the atmospheric circulation patterns producing significant daily rainfall in the Spanish Mediterranean area

Cited by 204 publications

References 21 publications

The influence of atmospheric circulation at different spatial scales on winter drought variability through a semi‐arid climatic gradient in Northeast Spain

The influence of atmospheric circulation at different spatial scales on winter drought variability through a semi‐arid climatic gradient in Northeast Spain

Daily atmospheric circulation catalogue for western Europe using multivariate techniques

Weather Patterns and Weather Types

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