Evaluation and analysis of daily atmospheric circulation patterns of the 500 HPA pressure field over the southwestern USA

Galambosi, Agnes; Duckstein, Lucien; Bogárdi, István

doi:10.1016/0169-8095(95)00025-9

Cited by 19 publications

(13 citation statements)

References 38 publications

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“…Kidson (1994) clustered 9 years of daily analyses (at 00 : 00h UTC) of 1000 hPa geopotential height over the New Zealand region, identifying 13 synoptic groups, assuming a less than perfect representation of the low-pressure centres. Over the southwestern USA, Galambosi et al (1996) applied these multivariate methodologies to daily 500 hPa pressure fields at 12 : 00 UTC, coupling PCA and clustering in order to describe and generate local hydrological variables. Applied to wind erosion events in sandy soil agricultural areas of southern Sweden, Ekstrom et al (2002) classified daily SLP circulation data and identified (via the definition of an index of erosion severity) the patterns associated with large erosion damage.…”

Section: Methodsmentioning

confidence: 99%

Atmospheric circulation patterns related to heavy snowfall days in Andorra, Pyrenees

et al. 2005

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Heavy snowfalls over mountain regions are often a direct cause of avalanches. Specific synoptic-scale atmospheric situations are responsible for these kinds of extreme snowfall event, and this is indeed the case for Andorra, a small country located in the Pyrenees, between France and Spain. Based on days with an intensity of at least 30 cm of snow in a 24 h period, the present study uses principal component analysis (PCA) and clustering techniques to characterize the synoptic circulation patterns for these days during the winter season. The area of analysis encompasses the region 30-60°N by 30°W-15°E and the period covers the winter seasons from 1986-87 to 2000-01. The methodology proposed involves a preprocessing approach consisting of a spatial standardization of the data used for the PCA, an alternative approximation to decide the centroids and the number of groups for the K-means clustering, and the rejection of the iterations for this algorithm. This approach enables the synoptic classification of every heavy snowfall day, and composite maps were constructed for sea-level pressure, 500 hPa geopotential height, and 1000-500 m thickness (the 5270 m, 5400 m and 5520 m contour lines). The results show seven circulation patterns, most of them with an Atlantic component of the wind, and others with a clear Mediterranean advection that could be combined with cold continental air. The results, as weather charts, could be a useful tool to assist meteorological models in heavy snowfall forecasting, and the day's classification obtained opens up future possibilities for detailed meteorological and climatological analysis of the established types.

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Section: Methodsmentioning

confidence: 99%

Atmospheric circulation patterns related to heavy snowfall days in Andorra, Pyrenees

et al. 2005

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“…Solman and Menén-dez (2003) found that daily winter 500 hPa geopotential heights over the southern part of the South American continent could be grouped into five frequently occurring circulation types and that two of the five circulation types had anomalously high frequencies during positive ENSO events. Galambosi et al (1996) classified 500 hPa pressure field heights over southwestern United States for each season into eight or nine classes and Burlando (2009) found that eight wind flow patterns adequately explained the wind climate over the Mediterranean.…”

Section: Introductionmentioning

confidence: 99%

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

Chadee

Clarke

2015

Clim Dyn

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“…Kidson, on the basis of S-mode and covariance dispersion matrix in PCA, used Ward's hierarchical CL to determine the number of groups and their centroids for the K-means algorithm. Over south-western USA, Galambosi et al (1996) applied these multivariate methodologies to daily 500 hPa pressure fields at 12:00 UTC (diamond structured grids), coupling PCA (S-mode of decomposition and correlation matrix) and CL (K-means) in order to describe and generate local hydrological variables. Galambosi et al (1996), as did Bogardi et al (1993), selected the number of groups for the K-means method in a subjective way, denoting this as a typical subjective step in the automated classification procedure.…”

Section: Introductionmentioning

confidence: 99%

“…Over south-western USA, Galambosi et al (1996) applied these multivariate methodologies to daily 500 hPa pressure fields at 12:00 UTC (diamond structured grids), coupling PCA (S-mode of decomposition and correlation matrix) and CL (K-means) in order to describe and generate local hydrological variables. Galambosi et al (1996), as did Bogardi et al (1993), selected the number of groups for the K-means method in a subjective way, denoting this as a typical subjective step in the automated classification procedure. 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.…”

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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Evaluation and analysis of daily atmospheric circulation patterns of the 500 HPA pressure field over the southwestern USA

Cited by 19 publications

References 38 publications

Atmospheric circulation patterns related to heavy snowfall days in Andorra, Pyrenees

Atmospheric circulation patterns related to heavy snowfall days in Andorra, Pyrenees

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

Daily atmospheric circulation catalogue for western Europe using multivariate techniques

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