introduction subtropical high pressure is one of the main elements of the general circulation of the atmosphere. annual motion of the circulation plays an important role in movement path of pressure systems and westerlies. hence, large parts of the planet are affected directly and indirectly by this system. sometimes the high pressure called the subtropical high pressure belt. it’s shown as sev...

â â â  this paper attempts to investigate the relationship between 500hpa circulation patterns and weather types (coldest, warmest and raining) over 16 synoptic stations of mountainous region of iran. the mountainous region of iran covers about 670000 square kilometer (41 percent) of iran. in this paper have been investigated the relationship between circulation patterns in 500hpa level with we...

Dust storm is a natural hazardous phenomenon that affects arid and semi-arid regions of the world same as Iran. The present research aims to investigate formation synoptic patterns pervasive dust storms (PDSs) in southwestern For this purpose, daily data visibility less than 1000m 16 stations (Ilam Khuzestan provinces) were reviewed during 2004–2017, 59 PDSs with more 2 days duration (overlappe...

1. introduction while human habitation was formed as concentrated and stable communities, air pollution had become perceptible on human life. by passing of time and the improvement of thriving and particularly by the industrial revolution commencement, air pollution gradually has converted into an international issue, principally in the present times (ghanbari and azizi, 1388: 16). whereas air ...

abstract many people know the important effects of caspian sea winds and storms on the economy of three provinces of iran including gilan, mazandaran, and golestan that they form one exclusive and extent area which have moderate and humid climate. this paper used a synoptic climatologically approach, which combine a number of atmospheric factors. using daily and monthly winds data including the...