Interannual and interdecadal variability of atmospheric synoptic-scale activity in the Southern Hemisphere

A rotated empirical orthogonal function analysis was applied to anomalies of July atmospheric short time scale variability (or storm tracks) over the Southern Hemisphere (SH) using NCEP reanalyses. The study reveals the existence of two leading modes of storm-track variations, the first one describi...

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Autor principal: Vera, C.
Formato: JOUR
Materias:
Interannual variations
Interdecadal variations
Southern Hemisphere
Storm tracks
Synoptic-scale variability
air-sea interaction
sea surface temperature
storm track
synoptic meteorology
temporal variation
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_01480227_v108_n4_pSOV4_Vera
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_01480227_v108_n4_pSOV4_Vera
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spelling todo:paper_01480227_v108_n4_pSOV4_Vera2023-10-03T15:00:53Z Interannual and interdecadal variability of atmospheric synoptic-scale activity in the Southern Hemisphere Vera, C. Interannual variations Interdecadal variations Southern Hemisphere Storm tracks Synoptic-scale variability air-sea interaction sea surface temperature Southern Hemisphere storm track synoptic meteorology temporal variation A rotated empirical orthogonal function analysis was applied to anomalies of July atmospheric short time scale variability (or storm tracks) over the Southern Hemisphere (SH) using NCEP reanalyses. The study reveals the existence of two leading modes of storm-track variations, the first one describing storm-track changes along the subtropical Paficic and the second one associated with variations over southeast Pacific Ocean. The principal components of both modes exhibit significant variability on interannual (2-7 years) and interdecadal (longer than 7 years) time scales. The interannual variation of the first mode is closely linked to ENSO variability. The corresponding signal on SST anomalies shows a conspicuous maximum over central equatorial Pacific, while the signature on geopotential-height anomalies shows the typical Pacific South America pattern characterized by a Rossby wave train propagating poleward from the tropics. On interdecadal time scales, the first mode is related to SST anomalies over the subtropical portions of the Pacific, Atlantic, and Indian Oceans and to a Rossby wave train with strongest signals over the southeast Pacific and the Antarctic Peninsula. The second mode that represents storm-track changes west of the Antarctic Peninsula is related on interannual time scales to SST anomalies over western Pacific between 40°S and 20°S, while on interdecadal time scales, it does not seem to be significantly related to SST changes in any of the basins. In particular, the spatial signature of the REOF2 interdecadal variability on the SH circulation corresponds to the well-known high latitude mode characterized by a monopole over the Antarctica and a three-wave pattern at middle latitudes. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_01480227_v108_n4_pSOV4_Vera
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Interannual variations
Interdecadal variations
Southern Hemisphere
Storm tracks
Synoptic-scale variability
air-sea interaction
sea surface temperature
Southern Hemisphere
storm track
synoptic meteorology
temporal variation
spellingShingle Interannual variations
Interdecadal variations
Southern Hemisphere
Storm tracks
Synoptic-scale variability
air-sea interaction
sea surface temperature
Southern Hemisphere
storm track
synoptic meteorology
temporal variation
Vera, C.
Interannual and interdecadal variability of atmospheric synoptic-scale activity in the Southern Hemisphere
topic_facet Interannual variations
Interdecadal variations
Southern Hemisphere
Storm tracks
Synoptic-scale variability
air-sea interaction
sea surface temperature
Southern Hemisphere
storm track
synoptic meteorology
temporal variation
description A rotated empirical orthogonal function analysis was applied to anomalies of July atmospheric short time scale variability (or storm tracks) over the Southern Hemisphere (SH) using NCEP reanalyses. The study reveals the existence of two leading modes of storm-track variations, the first one describing storm-track changes along the subtropical Paficic and the second one associated with variations over southeast Pacific Ocean. The principal components of both modes exhibit significant variability on interannual (2-7 years) and interdecadal (longer than 7 years) time scales. The interannual variation of the first mode is closely linked to ENSO variability. The corresponding signal on SST anomalies shows a conspicuous maximum over central equatorial Pacific, while the signature on geopotential-height anomalies shows the typical Pacific South America pattern characterized by a Rossby wave train propagating poleward from the tropics. On interdecadal time scales, the first mode is related to SST anomalies over the subtropical portions of the Pacific, Atlantic, and Indian Oceans and to a Rossby wave train with strongest signals over the southeast Pacific and the Antarctic Peninsula. The second mode that represents storm-track changes west of the Antarctic Peninsula is related on interannual time scales to SST anomalies over western Pacific between 40°S and 20°S, while on interdecadal time scales, it does not seem to be significantly related to SST changes in any of the basins. In particular, the spatial signature of the REOF2 interdecadal variability on the SH circulation corresponds to the well-known high latitude mode characterized by a monopole over the Antarctica and a three-wave pattern at middle latitudes.
format JOUR
author Vera, C.
author_facet Vera, C.
author_sort Vera, C.
title Interannual and interdecadal variability of atmospheric synoptic-scale activity in the Southern Hemisphere
title_short Interannual and interdecadal variability of atmospheric synoptic-scale activity in the Southern Hemisphere
title_full Interannual and interdecadal variability of atmospheric synoptic-scale activity in the Southern Hemisphere
title_fullStr Interannual and interdecadal variability of atmospheric synoptic-scale activity in the Southern Hemisphere
title_full_unstemmed Interannual and interdecadal variability of atmospheric synoptic-scale activity in the Southern Hemisphere
title_sort interannual and interdecadal variability of atmospheric synoptic-scale activity in the southern hemisphere
url http://hdl.handle.net/20.500.12110/paper_01480227_v108_n4_pSOV4_Vera
work_keys_str_mv AT verac interannualandinterdecadalvariabilityofatmosphericsynopticscaleactivityinthesouthernhemisphere
_version_ 1807317627597488128

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