Rossby wave propagation tracks in southern hemisphere mean basic flows associated to generalized frosts over southern South America
Titel:
Rossby wave propagation tracks in southern hemisphere mean basic flows associated to generalized frosts over southern South America
Auteur:
G. V. MÜLLER T. AMBRIZZI
Verschenen in:
Atmósfera
Paginering:
Jaargang 23 (2010) nr. 1 pagina's 25-35
Jaar:
2010
Inhoud:
Based on previous observational studies on cold extreme events over southern South America, some recent studies suggest a possible relationship between Rossby wave propagation remotely triggered and the occurrence of frost. Using the concept of linear theory of Rossby wave propagation, this paper analyzes the propagation of such waves in two different basic states that correspond to austral winters with maximum and minimum generalized frost frequency of occurrence in the Wet Pampa (central-northwest Argentina). In order to de- termine the wave trajectories, the ray tracing technique is used in this study. Some theoretical discussion about this technique is also presented. The analysis of the basic state, from a theoretical point of view and based on the calculation of ray tracings, corroborates that remotely excited Rossby waves is the mechanism that favors the maximum occurrence of generalized frosts. The basic state in which the waves propagate is what conditions the places where they are excited. The Rossby waves are excited in determined places of the atmosphere, propagating towards South America along the jet streams that act as wave guides, favoring the generation of generalized frosts. In summary, this paper presents an overview of the ray tracing technique and how it can be used to investigate an important synoptic event, such as frost in a specific region, and its relationship with the propagation of large scale planetary waves.
Uitgever:
Centro de ciencias de la atmósfera, Universidad nacional autonoma de México (provided by DOAJ)
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