Cyclogenesis is known to take place frequently near the principal mountain complexes of the earth. However, a coherent and comprehensive theory of orographic cyclogenesis has never been offered in the literature. We propose here a unified theory of cyclogenesis in the presence of orography of various configurations, based on the generalization of a theoretical model concerning the interaction of baroclinic waves with local orography. This model has recently proved to be successful in accounting for some basic properties of Alpinecyclogenesis (Speranza et al. 1985). We consider, in particular, cyclogenesis in proximity of the Rocky Mountains (both to the west of the ridge, in the Gulf of Alaska, and to the east of it, over North America) and in proximity of the Himalaya-Tibetan Plateau. With regard to cyclogenesis over the Gulf of Alaska, results of numerical experiments, performed with the ECMWF model in order to isolate the orographic effects in realistic conditions, are also presented and compared with the theoretical results.
A unified theory of orographic influences upon cyclogenesis
SPERANZA, Antonio;
1987-01-01
Abstract
Cyclogenesis is known to take place frequently near the principal mountain complexes of the earth. However, a coherent and comprehensive theory of orographic cyclogenesis has never been offered in the literature. We propose here a unified theory of cyclogenesis in the presence of orography of various configurations, based on the generalization of a theoretical model concerning the interaction of baroclinic waves with local orography. This model has recently proved to be successful in accounting for some basic properties of Alpinecyclogenesis (Speranza et al. 1985). We consider, in particular, cyclogenesis in proximity of the Rocky Mountains (both to the west of the ridge, in the Gulf of Alaska, and to the east of it, over North America) and in proximity of the Himalaya-Tibetan Plateau. With regard to cyclogenesis over the Gulf of Alaska, results of numerical experiments, performed with the ECMWF model in order to isolate the orographic effects in realistic conditions, are also presented and compared with the theoretical results.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
