the moisture flux convergence (mfc) and relative humidity in dusty days at different times and levels over the alvand mountain was investigated. the required basic data for the years 2009-2012, including relative humidity, visibility and synoptic codes, were gathered from hamadan synoptic station, while sea level pressure, uwind, vwind and specific humidity data were gathered from ncer/ncar sit...

mineral dust can directly affect the solar and terrestrial radiation in both visible and infrared (ir) spectral regions through scattering and absorption processes. due to specific optical properties of dust particles, satellite observed radiances carry the spectral signatures of dust particles that are different from molecular, cloud, and underlying surface. based on these differences, various...

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...

introduction climate change is an important environmental hazard that has been discussed in recent years. increasing the number or frequency of extreme climatic events such as severe droughts, floods, storms, heat and cold waves and heavy rains are the evidences of climate change. any of these events, due to the severity and persistence and their spread are a natural hazard that adverse effects...

there are a number of ideas to generate cloud and precipitation in the southern coasts of caspian sea, but none of them explain the cause of precipitation particularly heavy and super heavy precipitations precisely. this study describes main thermodynamic factors when the situation and location of synoptic patterns are effective. on the basis of daily data, monthly regimes and monthly trends of...