introductionmany aspect strongly influence regional climate includes localized surface processes, large-scale patterns, especially mid and upper level tropospheric circulation and many factors control precipitation in the west of iran includes location of emigrate westerly winds systems, jet streams location, humidity flux and topography. upper tropospheric jet stream constitutes a significant ...

introduction according to the definition of world meteorology organization (wmo), as the speed of the air mass is more than 30 meters per second, the jetstream will arise. the core of the jetstream is with baroclinic atmosphere due to the large difference in temperature and wind speed. there are two west jetstreams in the northern hemisphere. the northern jet stream is called polar front jetstr...

Abstract. Atmospheric jet streams are typically separated into primarily “eddy-driven” (or polar-front) jets and “thermally driven” subtropical) jets. Some regions also display “merged” jets, resulting from the (quasi-)collocation of eddy generation with subtropical jet. The different locations driving mechanisms these arise very underlying result in characteristics. Here, we link current under...

Many studies of tornado-severe local storms outbreaks have called attention to the role of the jet stream. In fact, the jet has become an accepted part of a climatological model for tornado occurrences in the central and southern Plains. This study undertakes to verify this acceptance by statistically testing the association between 500-mb. indications of the midlatitude and subtropical jet str...

in this paper meteorological conditions of some acute air pollution periods for the city of tehran have been considered. the data used were obtained from the air quality control company (aqcc) of municipality and from synoptic station of the institute of geophysics. initially some statistical methods were used to find the episodes for acute air pollution episodes, and then their meteorological ...

Over the past half-century, the ozone hole has caused a poleward shift of the extratropical westerly jet in the Southern Hemisphere. Here, we argue that these extratropical circulation changes, resulting from ozone depletion, have substantially contributed to subtropical precipitation changes. Specifically, we show that precipitation in the southern subtropics in austral summer increases signif...

5 The sensitivities of the Brewer-Dobson Circulation (BDC) to different distributions of trop6 ical SST heating are investigated in an idealized aqua-planet model. It is found that an 7 increase in tropical SSTs generally leads to an acceleration of tropical upwelling and an as8 sociated reduction in the Age of Air (AOA) in the polar stratosphere, and that the AOA 9 near the subtropical tropopa...

A dry primitive equation model is used to explain how the quasi-biennial oscillation (QBO) of the tropical stratosphere can influence the troposphere, even in the absence of tropical convection anomalies and a variable stratospheric polar vortex. QBO momentum anomalies induce a meridional circulation to maintain thermal wind balance. This circulation includes zonal wind anomalies that extend fr...

introduction jet stream is strong narrow current concentrated by strong vertical and lateral wind shears (vasantha et al, 2002). according to world meteorological organization nomenclature, jet stream formed when the speed of wind greater than 60 knots or 30 m/s. the major characteristics of the troposphere and lower stratosphere in the vicinity of jet streams were pointed out by a group of met...