Analysis of Relations between Dust Storms and Indus Low Pressure over Southern Iran

Iran is located in southern mid-latitudes and undergone to environment hazard of dust storms (DSs). In recent decades, following the climate change and the extensive environment destructions, the frequency of DSs has increased and the visibility during dusty days has decreased over Western and Southern Iran (SI). As the aim of present study, we followed the classifying of DSs in SI based on their frequencies related to Indus Low (IL) characteristics including its pressure and location. The daily data-set of this research included 11 dust codes that gathered from 17 weather stations in the SI at 12 UTC from 2000 to 2009. 120 daily graphs that were plotted based on the frequency of dusty cities, determined 354 DSs. All DSs were classified in three categories including pervasive, semi-pervasive, and small ones and they determined 25 DSs as indicator ones based on their frequency of dusty cities and their dates. SLP data-sets during all dates at 12 UTC related to every category composed by C programming and it presented final composed models on sea level pressure. Composed model showed IL is strong and unified during Pervasive DSs (PDS) over Indus Plain as IL location. It revealed dusts were sucked and moved from two principal “routes” including “Southern Sahara-Hijaz-Southern Iran” and “Syria-Iraq-Southern Iran” and one subsidiary route “Central Asia-Southern Iran” during PDSs toward Indus Plain. All routes of IL were subsidiary, surface and scattered during Semi-pervasive DSs and we didn’t find any route during small DSs. West-ward air flows and decrease in relative humidity at low troposphere over South-eastern Iran as two findings from previous researchers and deepening and being focused of IL as a new finding are three indicators that can used for DS monitoring and warning and then environment management.