dust is a common atmospheric phenomenon in iran especially in central arid regions.  this severely affects environment as well as resident’s health. among the results of this phenomenon are respiratory diseases, bash radiation, accelerated soil erosion, desertification and degradation of ecosystems. some dusts are originated from local desert conditions but adjacency to neighboring countries de...

introduction thunderstorms of the most important, most abundant of the most severe weather hazard that each year, in addition to large quantities of crops and infrastructure development, causing human casualties are also around the globe. between 1953 and 1957 the financial losses caused by the hurricanes in america has over 3.6 million dollars (changnon;2003,1231).storms of varying intensities...

The influence of synoptic circulation patterns on surface ozone concentrations at three monitoring sites in southern Sweden was investigated for the spring (April–May) and summer (June–August) periods 1990–2005. Synoptic circulation patterns were classified into six groups based on the Lamb Weather Types (LWTs). The analyses show that the anticyclonic weather pattern (A) and the directional flo...

The derivation of the meridional momentum flux arising from a multiscale horizontal velocity field in the intraseasonal, planetary, equatorial synoptic-scale dynamics (IPESD) multiscale models of the equatorial troposphere is presented. It is shown that, because of the balance dynamics on the synoptic scales, the synoptic-scale component of the meridional momentum flux convergence must always v...

One of the unexplained striking features of tropical convection is the observed statistical self-similarity, in clusters, superclusters, and intraseasonal oscillations through complex multi-scale processes ranging from the mesoscales to the equatorial synoptic scales to the intraseasonal/planetary scales. Here new multi-spatial scale, multi-time scale, simplified asymptotic models are derived s...