Synoptic and dynamical analysis of subtropical cyclone Anita (2010) and its potential for tropical transition over the South Atlantic Ocean

Pinto, João Rafael Dias; Reboita, Michelle Simões; Rocha, Rosmeri Porfírio da

doi:10.1002/jgrd.50830

Cited by 45 publications

(63 citation statements)

References 58 publications

(78 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…There is no clear division between the classes, which allows the existence of cyclones with mixed characteristics and transformation between types (transitions). This approach evidences the idea of cyclones as a continuum and not strictly separated in classes (Beven 1997) and has been widely used in the study of SCs all over the globe; for the parameters, equations, and application to the Southern Hemisphere, see Dias Pinto and da Rocha (2011) andDias Pinto et al (2013).…”

Section: A Datamentioning

confidence: 98%

“…It did not develop over high SST, but cold air aloft, associated with a midtropospheric trough, reinforced the upward motion and convective activity, while a persistent upper-level Rex blocking pattern (Rex 1950) was responsible for weakening the vertical wind shear and the eastward steering of the cyclone (McTaggartCowan et al 2006). In March 2010, the subtropical storm Anita developed in a very similar upper-level condition of dipole blocking, and although the interaction with another extratropical disturbance prevented the system from undergoing tropical transition (Dias Pinto et al 2013), it acquired all the characteristics of a well-organized SC.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Subtropical Cyclones over the Southwestern South Atlantic: Climatological Aspects and Case Study

et al. 2014

View full text Add to dashboard Cite

Hurricane Catarina (2004) and subtropical storm Anita (2010) called attention to the development of subtropical cyclones (SCs) over the South Atlantic basin. Besides strong and organized storms, a large number of weaker, shallower cyclones with both extratropical and tropical characteristics form in the region, impacting the South American coast. The main focus of this study is to simulate a climatology of subtropical cyclones and their synoptic pattern over the South Atlantic, proposing a broader definition of these systems. In addition, a case study is presented to discuss the main characteristics of one weak SC. The Interim ECMWF Re-Analysis (ERAInterim) and NCEP-NCAR reanalysis are used to construct the 33-yr (1979-2011) climatology, and a comparison between them is established. Both reanalyses show good agreement in the SCs' intensity, geographical distribution, and seasonal variability, but the interannual variability is poorly correlated. Anomaly composites for austral summer show that subtropical cyclogenesis occurs under a dipole-blocking pattern in upper levels. Upward motion is enhanced by the vertical temperature gradient between a midtropospheric cold cutoff low/trough and the intense low-level warm air advection by the South Atlantic subtropical high. Turbulent fluxes in the cyclone region are not above average during cyclogenesis, but the subtropical high flow advects great amounts of moisture from distant regions to fuel the convective activity. Although most of the SCs develop during austral summer (December-February), it is in autumn (March-May) that the most ''tropical'' environment is found (stronger surface fluxes and weaker vertical wind shear), leading to the most intense episodes.

show abstract

Section: A Datamentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Subtropical Cyclones over the Southwestern South Atlantic: Climatological Aspects and Case Study

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Dias Pinto et al . () conducted a synoptic and dynamic analysis of the SC Anita and its potential tropical transition (TT) in March 2010 near the coast of southern Brazil in the Atlantic Ocean. Anita started as a SC, then evolved into a state favourable for TT and later developed a cold core structure, becoming an extratropical cyclone.…”

Section: Introductionmentioning

confidence: 98%

Synoptic analysis of an intense rainfall event in Paraíba do Sul river basin in southeast Brazil

Brasiliense

Dereczynski

Satyamurty

et al. 2017

Meteorological Applications

View full text Add to dashboard Cite

ABSTRACT:The aim of this study was to analyse the characteristics of an intense rainfall event that occurred in the Paraíba do Sul river basin, southeast Brazil, in early 2000. Rainfall data from conventional meteorological stations and automatic weather stations, satellite images and datasets from the Climate Forecast System Reanalysis, National Centers for Environmental Prediction, were employed. After the arrival of a cold front in the state of São Paulo on 1 January, the first episode of the South Atlantic convergence zone (SACZ) of the year was established, lasting for 8 days. A dipole blocking pattern over the state of Rio Grande do Sul and Uruguay, with a cold core cyclone and a warm core anticyclone in the upper troposphere, weakened the westerly flow from the Pacific, favouring slow displacement of the SACZ. Intense moisture fluxes from the southern Amazon and tropical South Atlantic converged over southeast Brazil providing copious amounts of moisture for convective activity during the first 4 days of January 2000. The most notable aspect of this event was the development of a cyclonic vortex embedded in the SACZ (CVES) in the Atlantic Ocean, with a warm core in the lower troposphere and a cold core at higher levels, which intensified rain in the study region. After the weakening of the blocking on 4 January, the CVES moved southeastward in the Atlantic. The symmetry of the CVES and conditions of the thermal gradient in the lower and higher troposphere suggest that the system presented subtropical characteristics during the first few days and became an extratropical cyclone later.

show abstract

“…Subtropical cyclones are nonfrontal low‐pressure systems with a thermally hybrid core (warm at low levels and cold at upper levels) and intense convective activity that develop mostly over the oceanic areas. Their occurrence over South America, more specifically in the southwestern South Atlantic, is documented in a number of case studies [ McTaggart‐Cowan et al , ; Veiga et al , ; Pereira‐filho et al , ; Vianna et al , ; Dias Pinto et al , ], and the climatology of such systems is presented in Evans and Braun [] and Gozzo et al []. This is still an incipient research area, and a better comprehension of subtropical cyclone (SC) development is important in a theoretical point of view and also to improve operational weather forecast.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, SCs in southwestern South Atlantic occurs where there is large moisture content in lower levels of the troposphere [ Dias Pinto et al , ; Gozzo et al , ]. If local evaporation during these events is not unusually intense, the transport of water vapor from distant regions by the atmospheric circulation should be a vital moisture source.…”

Section: Introductionmentioning

confidence: 99%

Climatology and numerical case study of moisture sources associated with subtropical cyclogenesis over the southwestern Atlantic Ocean

et al. 2017

View full text Add to dashboard Cite

An important feature during cyclogenesis is the availability of moisture to fuel the associated convective activity providing faster developments and more intense systems. In this work, an investigation of the role of local evaporation and remote water vapor transport prior to subtropical cyclogenesis in the southwestern South Atlantic (named RG1 region) is presented. Results were obtained analyzing the period from 1980 to 2015 with a Lagrangian particle dispersion model together with the ERA‐Interim reanalysis. The northern sector of the Subtropical High in the South Atlantic Ocean stands out as the main source region of water vapor to the RG1, with the low‐level northeasterly winds being responsible by moisture transport. An anomalous moisture transport from lower latitudes preceded the subtropical cyclogenesis events and provided the necessary water vapor to fuel the convective activity. A numerical case study using the Weather Research and Forecasting mesoscale model indicated that the remote moisture source is essential for subtropical cyclogenesis in RG1, since it allows a stronger surface low pressure to develop and supports the formation of a cutoff low in the middle troposphere. Though the local evaporation has a secondary role in this process, it helped the system to attain the observed intensity and subtropical characteristics. Therefore, both local and remote moisture sources provide the incipient subtropical cyclone with the horizontal temperature advection and convective activity necessary to its further development.

show abstract

Synoptic and dynamical analysis of subtropical cyclone Anita (2010) and its potential for tropical transition over the South Atlantic Ocean

Cited by 45 publications

References 58 publications

Subtropical Cyclones over the Southwestern South Atlantic: Climatological Aspects and Case Study

Subtropical Cyclones over the Southwestern South Atlantic: Climatological Aspects and Case Study

Synoptic analysis of an intense rainfall event in Paraíba do Sul river basin in southeast Brazil

Climatology and numerical case study of moisture sources associated with subtropical cyclogenesis over the southwestern Atlantic Ocean

Contact Info

Product

Resources

About