| Institution: | 1.Department of Geography,University of Chile,Santiago,Chile;2.Climatology Group,University of Barcelona,Barcelona,Spain;3.CITRID, Risk Reduction And Disaster Program,University of Chile,Santiago,Chile;4.Departamento de Ciencias Históricas y Geográficas,Universidad de Tarapacá,Arica,Chile;5.Department of Social Sciences,University of Los Lagos,Osorno,Chile;6.Department of Applied Economy,University of Santiago de Compostela,Santiago de Compostela,Spain;7.Institute of Oceans and Fisheries,University of Bristish Columbia,Vancouver,Canada |
| Abstract: | Atmospheric circulation patterns in southern Chile (42° 30′ S) were studied in order to determine and analyse the most characteristic synoptic types and their recent trends, as well as to gain an understanding of how they are associated with low-frequency variability patterns. According to the Jenkinson and Collison (J&C) classification method, a 16-point grid of sea-level pressure data was employed. The findings reveal that some synoptic types show statistically significant trends with a 95% confidence level, positively for anticyclonic westerly hybrids (AW) and advective types for third and fourth quadrant wind flows (W, NW, and N) and negatively for SW and cyclonic hybrids (CS and CSW). A model has been constructed of the linear regression of some weather types with teleconnections that most affect Chile: the undetermined types (U), AW were associated with El Niño or the warm phase of the Pacific Decadal Oscillation (PDO), whereas the cyclonic northerly and cyclonic northeasterly types (CN and CNE) were associated with La Niña or cool phase of the PDO. The weather types associated with Antarctic Oscillation (AAO) in its positive phase are anticyclonic northerly and northeasterly and northerly advection types, while in its negative phase are cyclonic southwesterly and advection types. |
