Surface circulation associated with frost in the wet Pampas

Müller, Gabriela V.; Compagnucci, Rosa Hilda; Núñez, Mario N.; Salles, Alejandra

doi:10.1002/joc.907

Cited by 34 publications

(19 citation statements)

References 28 publications

(24 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Many other works have been proposed, showing different approximations on daily circulation pattern classification via PCA and CL techniques (Plaut and Simonnet, 2001;Skinner et al, 2002;Solman and Menéndez, 2003;Rasilla, 2003;Müller et al, 2003). This extensive bibliography shows the robustness of the method for daily circulation pattern classifications, but does not yet clarify what the best options to be chosen are, leaving this decision to the researcher.…”

Section: Introductionmentioning

confidence: 99%

Daily atmospheric circulation catalogue for western Europe using multivariate techniques

Esteban

Martín‐Vide

Mases³

2006

Intl Journal of Climatology

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

Daily atmospheric circulation catalogue for western Europe using multivariate techniques

Esteban

Martín‐Vide

Mases³

2006

Intl Journal of Climatology

View full text Add to dashboard Cite

show abstract

“…Figure 12(c)). This pattern may be associated with the third PC (Pattern C) for the group of the La Niña years studied in the synoptic-climatic classification by Müller et al (2003). It is interesting to note that the studied winters (i.e.…”

Section: Daily Composites Of Partial Frostsmentioning

confidence: 66%

“…The main synoptic types associated with frosts in the studied region correspond to anticyclone situations determining radiative and/or advective frosts. This was demonstrated in Müller et al (2003) on the basis of the climatic-synoptic classification of circulation patterns comprising the PF + GF days during the winters of the period 1972-1983. In addition, the opposite extreme (−σ ) occurs when the positive anomaly is located over the Southern Atlantic in front of the Argentine coast, with an increase in the northerly wind (relatively warmer and more humid) in the Pampas region, which does not favor frost occurrence.…”

Section: Criteria Data and Methodologymentioning

confidence: 98%

See 1 more Smart Citation

Patterns leading to extreme events in Argentina: partial and generalized frosts

Müller

2007

Intl Journal of Climatology

View full text Add to dashboard Cite

Abstract:This paper studies the atmospheric circulation associated with frosts in the central region of Argentina with the objective of improving the prediction capacity for these events. Frosts are selected according to a spatial principle, which takes into consideration those events affecting an area above 25% of the weather stations located in the region known as Wet Pampas. Partial frosts (PF, less than 75% of the stations) and generalized frosts (GF, above 75% of the stations) constitute two different groups: one of them given by PF + GF and the other one only by the PFs. The analysis comprises the period between 1961 and 1990, where two extremes are selected: those years with a number of frosts one standard deviation above and below the mean (+σ and −σ respectively). In each extreme group (i.e. PF + GF +σ and −σ ; PF +σ and −σ ), the average number of frosts varies according to the different periods of the year. Therefore, the following periods -selected independently -are studied: Annual of frosts (from April through October), seasonal (from May through September and from June through August), and each of the involved months individually.The mean circulation patterns analyzed from the composites of different meteorological variables explain the temperature anomalies observed in the region under study. In this way, the extreme occurrence of frosts is a result of the prevailing circulation during the different periods under consideration. Within each group (PF + GF and PF), the composites of the extremes +σ and −σ show opposite anomaly patterns for the different periods. Results for +σ (−σ ) are distinguished by negative (positive) temperature and humidity anomalies in the Wet Pampas for the composites of PF + GF and PF. At low levels, the wind anomalies show the prevalence of winds from the south (north) in the southern section of the continent. At upper levels, this pattern is accompanied by anomalies of the prevailing westerly (easterly) wind for PF + GF and PF. This means a subtropical jet over South America more (less) intense than normal is associated with a higher (lower) frequency of frost occurrence in the seasonal composites and the Annual.However, there are variations in wind anomalies at 250 hPa within the same extreme +σ (−σ ) when comparing the groups' PF with the previously studied group (formed only by the GF). Composites of group GF +σ showed a maximum anomaly of the westerly zonal wind located at the jet entrance region into South America, over the Andes. On the other hand, the composites for PF +σ show a component from the northwest located leeward the Andes, extending toward the southeast up to the Atlantic Ocean. The same anomaly for the extreme −σ extends from the north of Argentina up to tropical latitudes, and it is more intense for groups PF + GF and PF than for group GF.Additionally, an analysis of the daily evolution of PF events during winters' GF +σ shows that the PFs are caused by a cyclonic anomaly moving toward the east of the continent, causing cold air advection from the so...

show abstract

“…More details about missing data are discussed in Section 3. 41 (Müller et al, 2002) or blocking action systems (Alessandro, 2003). The PCA method was used to characterise synoptic situations associated with recirculation.…”

Section: Recirculation Indexmentioning

confidence: 99%

Weather conditions associated with the potential for pollen recirculation in a coastal area

Gassmann

Gardiol

2007

Meteorological Applications

View full text Add to dashboard Cite

This study aims to characterise the main synoptic field patterns associated with the potential for recirculation of pollen. A recirculation index (R) was calculated in the area of Mar del Plata, Argentina. The daily development of sea-land breeze and the related monthly frequencies of wind directions were studied. The sea breeze was present for 36.2% of the time, with a mean lifetime of about 2 h in winter and 15-20 h in summer. Recirculation of the air had an annual frequency of around 7%, with a net transport from the city outskirts towards the sea, for 39.4% of the year, and a net inland transport frequency of 38.4%. The Rotated Principal Component Analysis (PCA) was applied to obtain synoptic field patterns associated with potential conditions for recirculation in the area. It was shown that low-pressure systems or troughs between 45°and 60°S (i.e. over the country, the South Pacific and/or the South Atlantic and two anticyclones located in the Atlantic or South Pacific Oceans) are the most common weather conditions associated with air recirculation in the coastal area of Buenos Aires province. A case study with high night pollen concentrations was also analysed.

show abstract

Surface circulation associated with frost in the wet Pampas

Cited by 34 publications

References 28 publications

Daily atmospheric circulation catalogue for western Europe using multivariate techniques

Daily atmospheric circulation catalogue for western Europe using multivariate techniques

Patterns leading to extreme events in Argentina: partial and generalized frosts

Weather conditions associated with the potential for pollen recirculation in a coastal area

Contact Info

Product

Resources

About