drought is one of the natural disasters that causes a lot of damages each year. this phenomenon is a result of severe and repeated spatial-temporal anomalies in atmosphere circulation patterns. thus, studying and identifying the synoptic patterns of this phenomenon is inevitably necessary. in this study, first yearly rainfalls in selected stations of the uremia lake basin were temporally standa...

introduction although temperatures in 0 and below 0 c° in the cold season of the year and mid latitudes are not necessarily considered an extreme phenomenon, but their long-term durability in a widespread area or their sudden occurrence in the beginning and end of the cold season can make this faetor an extreme extent phenomenon. the extreme phenomena are resulted from interaction between large...

This study addresses the role of soil moisture and its interaction with the overlying atmosphere in setting up climate anomalies over South America during El Niño years using observations as well as Atmospheric General Circulation Model (AGCM) simulations. It is found that during summertime land–atmosphere interaction is instrumental in setting the spatial pattern and sign of surface air temper...

A new and distinctly interdecadal signal in the climate of the Pacific Ocean has been uncovered by examining the coupled behavior of sea surface temperatures (SSTs) and Northern Hemisphere atmospheric circulation. This interdecadal Pacific signal (IPS) of ocean–atmosphere interaction exhibits a highly statistically significant interdecadal component yet contains little to no interannual (El Niñ...

introduction dust storms, one type of dust event, are in most cases the result of turbulent winds, including convective haboobs, which raise large quantities of dust from desert surfaces and reduce visibility to less than 1 km. this dust reaches concentrations in excess of 6000 mg m3 in severe events. the major dust source regions are areas of arid and hyper-arid, with mean annual rainfalls of ...

â â  in this research, temporal and spatial behavior of subtropical high pressure was studied at the level of 600 hpa. this study has been done using daily data of geopotential height at 12 gmt in ncep/ncar database with spatial resolution of 2.5ã—2.5 degree in a 55 years period including 20089 days from january, 1st, 1951(dey, 11th, 1329) to december, 31st,2005(dey, 10th,1384). at first, the m...

The 3D structures of the free oscillations of an adiabatic and hydrostatic atmosphere around a basic state at rest were used as a physical filtering for atmospheric data. This filtering procedure allows for the consideration of the three primitive variables (u, y, f) over the whole atmosphere simultaneously. Accordingly, the computed statistics do not simply rely on the information provided by ...