DOI: 10.1002/joc.5744
论文题名: Atmospheric characteristics that induce extreme precipitation in frontal systems over Southeastern Brazil during summer: Observations and atmospheric model simulation
作者: M. Andrade K. ; F. A. Cavalcanti I.
刊名: International Journal of Climatology
ISSN: 8998418
出版年: 2018
卷: 38, 期: 14 起始页码: 5368
结束页码: 5385
语种: 英语
英文关键词: AGCM
; atmospheric anomalies
; cold fronts
; precipitation extremes
; South America
Scopus关键词: Kinetic energy
; Kinetics
; Moisture
; Rain
; AGCM
; Atmospheric anomaly
; Cold front
; Precipitation extremes
; South America
; Atmospheric humidity
; Antarctic Oscillation
; atmospheric general circulation model
; atmospheric modeling
; cold front
; extreme event
; humidity
; Madden-Julian oscillation
; precipitation (climatology)
; summer
; Brazil
英文摘要: Cold fronts are the most frequent synoptic systems that affect Southeast Brazil during the whole year. The highest frequency of these systems at these latitudes occurs in the months of spring (SON) and winter (JJA), but the highest associated precipitation occurs in the spring (SON) and summer (DJF). Some of these fronts present light rains but others cause heavy precipitation, giving rise to flooding and landslides, mainly in the summer. Composites of the two cases (light and heavy rainfall) are analysed for the summer season. Large-scale and regional features are shown to discuss the differences in precipitation. Regional differences are seen in the position and intensity of low pressure and postfrontal high. The differences are also associated with the humidity flux and convergence over the region. The main difference at high levels is the position of the frontal trough, which is close to the region in the wet cases and displaced to the ocean in the dry cases. Features of the Southern Annular Mode and Madden–Julian Oscillation show opposite patterns in the two cases. These modes of variability can modulate extra-tropical wave trains over the Pacific, which have different behaviour downstream, over South America and South Atlantic Ocean. The eddy kinetic energy is stronger over Southeastern Pacific and Southern South America, and wave activity shows energy propagation towards the continent in the wet cases. Similar analyses with results of a global atmospheric model show that the general atmospheric characteristics of a frontal system are reproduced, as the temperature gradient, the wind confluence and the ridge-trough pair associated with the frontal system. The model represents the differences with respect to moisture flux and the frontal trough position, but underestimates the moisture convergence, eddy kinetic energy and wave activity, in the wet cases. © 2018 Royal Meteorological Society Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/116721
Appears in Collections: 气候减缓与适应
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作者单位: Center for Weather Forecasting and Climate Studies, National Institute for Space Research, São Paulo, Brazil
Recommended Citation:
M. Andrade K.,F. A. Cavalcanti I.. Atmospheric characteristics that induce extreme precipitation in frontal systems over Southeastern Brazil during summer: Observations and atmospheric model simulation[J]. International Journal of Climatology,2018-01-01,38(14)