Upper-level cut-off lows in southern South America
This paper presents a statistical study of the spatial and seasonal distribution and duration of cut-off low systems over the southern South American region based on the NCEP- NCAR reanalysis data for the period 1979-1988. Cut-off lows were first objectively determined as minimum geopotential values...
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_01777971_v96_n1-2_p181_Campetella |
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todo:paper_01777971_v96_n1-2_p181_Campetella2023-10-03T15:08:08Z Upper-level cut-off lows in southern South America Campetella, C.M. Possia, N.E. geopotential low pressure system spatial distribution statistical analysis South America This paper presents a statistical study of the spatial and seasonal distribution and duration of cut-off low systems over the southern South American region based on the NCEP- NCAR reanalysis data for the period 1979-1988. Cut-off lows were first objectively determined as minimum geopotential values at the 250 hPa level and then subjectively imposing a cut-off circulation and a cold core. A total of 171 cut-off low events were detected, being more frequent in austral autumn followed by winter, spring and summer. There is a preferential region of occurrence in spring and autumn located between 68°-80° W and 30°-45° S. The Pacific area showed the greatest frequency of occurrence followed by the Atlantic and the continental areas. Most of the cut-off lows last 2 or 3 days (around 90% of the cases) though there is a tendency of the continental events to be longer. The cut-off low event developed upwind the Andes on 22-28 September 1986 was selected as a case study. Low-level cold air advection was the main forcing of the deepening of the upper level low system. © Springer-Verlag 2006. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_01777971_v96_n1-2_p181_Campetella |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
geopotential low pressure system spatial distribution statistical analysis South America |
| spellingShingle |
geopotential low pressure system spatial distribution statistical analysis South America Campetella, C.M. Possia, N.E. Upper-level cut-off lows in southern South America |
| topic_facet |
geopotential low pressure system spatial distribution statistical analysis South America |
| description |
This paper presents a statistical study of the spatial and seasonal distribution and duration of cut-off low systems over the southern South American region based on the NCEP- NCAR reanalysis data for the period 1979-1988. Cut-off lows were first objectively determined as minimum geopotential values at the 250 hPa level and then subjectively imposing a cut-off circulation and a cold core. A total of 171 cut-off low events were detected, being more frequent in austral autumn followed by winter, spring and summer. There is a preferential region of occurrence in spring and autumn located between 68°-80° W and 30°-45° S. The Pacific area showed the greatest frequency of occurrence followed by the Atlantic and the continental areas. Most of the cut-off lows last 2 or 3 days (around 90% of the cases) though there is a tendency of the continental events to be longer. The cut-off low event developed upwind the Andes on 22-28 September 1986 was selected as a case study. Low-level cold air advection was the main forcing of the deepening of the upper level low system. © Springer-Verlag 2006. |
| format |
JOUR |
| author |
Campetella, C.M. Possia, N.E. |
| author_facet |
Campetella, C.M. Possia, N.E. |
| author_sort |
Campetella, C.M. |
| title |
Upper-level cut-off lows in southern South America |
| title_short |
Upper-level cut-off lows in southern South America |
| title_full |
Upper-level cut-off lows in southern South America |
| title_fullStr |
Upper-level cut-off lows in southern South America |
| title_full_unstemmed |
Upper-level cut-off lows in southern South America |
| title_sort |
upper-level cut-off lows in southern south america |
| url |
http://hdl.handle.net/20.500.12110/paper_01777971_v96_n1-2_p181_Campetella |
| work_keys_str_mv |
AT campetellacm upperlevelcutofflowsinsouthernsouthamerica AT possiane upperlevelcutofflowsinsouthernsouthamerica |
| _version_ |
1782028139578261504 |