پایش آماری پدیده ی گرد و غبار در استان خوزستان بارویکرد ساعتی

ﮔﺮدوﻏﺒﺎر ﺑﻪ رﺳﻮﺑﺎت ﺑﺎ اﻧﺪازه ﮐﻤﺘﺮ از 100ﻣﯿﮑﺮون ﮐﻪ ﺑﻪ ﺻﻮرت ذرات ﻣﻌﻠﻖ اﻧﺘﻘﺎل ﻣﯽﯾﺎﺑﺪ، اﻃﻼق ﻣﯽﺷﻮد. ﺗﻮﻓﺎنﻫﺎی ﮔﺮدوﻏﺒﺎر ﻫﺮ ﺳﺎل در ﻣﻨﺎﻃﻖ ﺧﺸﮏ و ﻧﯿﻤﻪﺧﺸﮏ در ﻋﺮضﻫﺎی ﺟﻨﺐﺣﺎره رخ ﻣﯽدﻫﺪ. ﻣﻨﻄﻘﻪ ﻏﺮب آﺳﯿﺎ، از ﺟﻤﻠﻪ ﺷﺒﻪ ﺟﺰﯾﺮه ﻋﺮﺑﺴﺘﺎن، ﻋﺮاق و اﯾﺮان و ﻣﺨﺼﻮﺻﺎ ﺧﻮزﺳﺘﺎن ﺑﻪ ﻋﻨﻮان ﯾﮑﯽ از ﻣﻬﻤﺘﺮﯾﻦ ﻣﻨﺎﺑﻊ ﮔﺮدوﻏﺒﺎر ﺷﻨﺎﺧﺘﻪ ﺷﺪهاﺳﺖ . ﻫﺪف از اﯾﻦ ﭘﮋوﻫﺶ ﺑﺮرﺳﯽ ﻓﺮاواﻧﯽ و ﻣﯿﺰان روﻧﺪ ﭘﺪﯾﺪه ﮔﺮدوﻏﺒﺎر در ﻣﻘﯿﺎس ﺳﺎﻋﺘﯽ، ﻣﺎﻫﺎﻧﻪ، ﻓﺼﻠﯽ و ﺳﺎﻻﻧﻪ ﻃﯽ دوره آﻣﺎری 1995-2015 در اﺳﺘﺎن ﺧﻮزﺳﺘﺎن ﻣﯽﺑﺎﺷﺪ. روش ﮐﺎر در اﯾﻦ ﭘﮋوﻫﺶ ﻣﺒﺘﻨﯽ ﺑﺮ ﻣﺤﺎﺳﺒﻪ آﻣﺎری ﭘﺎراﻣﺘﺮﻫﺎی ﻣﺮﺑﻮط ﺑﻪ رﯾﺰﮔﺮد و ﺗﺠﺰﯾﻪ ﺗﺤﻠﯿﻞ آﻣﺎری دادهﻫﺎ ﺑﻪ روش ﯾﺮآورد ﺷﯿﺐ ﺳﻦ و آزﻣﻮن ﻣﻦ-ﮐﻨﺪال و ﺗﻬﯿﻪ ﻧﻘﺸﻪﻫﺎی ﺗﻮزﯾﻊ ﻓﻀﺎﯾﯽ ﭘﺪﯾﺪه ﮔﺮدوﻏﺒﺎر ﻣﯽﺑﺎﺷﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد 78/57 درﺻﺪ روﯾﺪادﻫﺎی ﮔﺮدوﻏﺒﺎری ﺑﯿﻦ ﺳﺎﻋﺎت 15/30-9/30ﺑﻪ وﻗﺖ ﻣﺤﻠﯽ ﻫﻤﺰﻣﺎن ﺑﺎ ﮔﺮﻣﺎﯾﺶ زﯾﺎد زﻣﯿﻦ، ﺧﺸﮑﯽ ﺧﺎک و اﺧﺘﻼف ﻓﺸﺎر ﻣﺤﻠﯽ اﺗﻔﺎق اﻓﺘﺎده اﺳﺖ. ﻣﺤﺎﺳﺒﻪ روﻧﺪ در ﻫﻤﻪ ﺳﺎﻋﺎت روز روﻧﺪ اﻓﺰاﯾﺸﯽ و ﻣﻌﻨﺎدار را ﻧﺸﺎن داده اﺳﺖ ﮐﻪ ﺑﯿﺸﺘﺮﯾﻦ اﻓﺰاﯾﺶ ﻣﺮﺑﻮط ﺑﻪ ﺳﺎﻋﺖ 12/30 و 9/30 ﺷﺐ ﻣﯽﺑﺎﺷﺪ. 49درﺻﺪ روزﻫﺎی ﮔﺮدوﻏﺒﺎری ﺑﻪ ﺗﺮﺗﯿﺐ ﻣﺮﺑﻮط ﺑﻪ ﻣﺎهﻫﺎی ژوﺋﯿﻪ، ژوﺋﻦ و ﻣﯽ ﻣﯽﺑﺎﺷﺪ ﻫﻤﭽﻨﯿﻦ 73 درﺻﺪ روزﻫﺎی ﮔﺮدوﻏﺒﺎری در ﻓﺼﻮل ﺑﻬﺎر و ﺗﺎﺑﺴﺘﺎن رخ دادهاﺳﺖ ﮐﻪ ﻣﺮﺗﺒﻂ ﺑﺎ اﻓﺰاﯾﺶ دﻣﺎ و ﺧﺸﮑﯽ ﻣﻨﺎﺑﻊ آب و ﺧﺎک در اﺳﺘﺎن ﺧﻮزﺳﺘﺎن اﺳﺖ. ﺗﻮزﯾﻊ ﻓﻀﺎﯾﯽ ﮔﺮدوﻏﺒﺎر ﺑﻪ ﺻﻮرت ﻓﺼﻠﯽ و ﺳﺎﻻﻧﻪ ﻧﺸﺎن ﻣﯽدﻫﺪ ﺑﯿﺸﺘﺮﯾﻦ روزﻫﺎی ﮔﺮدوﻏﺒﺎر در ﻫﻤﻪ ﻓﺼﻮل ﻣﺮﺑﻮط ﺑﻪ ﻧﯿﻤﻪ ﻏﺮﺑﯽ اﺳﺘﺎن اﺳﺖ ﮐﻪ ﻧﺸﺎندﻫﻨﺪه ﻏﻠﺒﻪ ﮐﺎﻧﻮنﻫﺎی ﺧﺎرﺟﯽ ﺑﻪ ﻋﻨﻮان ﻣﻨﺸﺎ اﺻﻠﯽ رﯾﺰﮔﺮد و اﻫﻤﯿﺖ ﻋﺎﻣﻞ ﺗﻮﭘﻮﮔﺮاﻓﯽ در اﯾﻦ ﻣﻨﻄﻘﻪ ﻣﯽﺑﺎﺷﺪ. ﺗﻮزﯾﻊ ﻓﻀﺎﯾﯽ آﻣﺎره q ﻧﯿﺰ ﻣﺒﯿﻦ اﻓﺰاﯾﺶ ﺷﺪﯾﺪ رﯾﺰﮔﺮد در ﺑﯿﺴﺖ ﺳﺎل اﺧﯿﺮ در ﻧﻮاﺣﯽ ﺟﻨﻮب ﺷﺮﻗﯽ ، ﺟﻨﻮب و ﻣﺮﮐﺰی اﺳﺘﺎن و در ﺳﺎﻋﺎت ﭘﺎﯾﺎﻧﯽ روز ﻣﯽﺑﺎﺷﺪ ﮐﻪ ﺑﯿﺎﻧﮕﺮ ﺗﻮﺳﻌﻪ ﻓﻌﺎﻟﯿﺖ ﮐﺎﻧﻮنﻫﺎی داﺧﻠﯽ در اﻓﺰاﯾﺶ روﻧﺪ رﯾﺰﮔﺮد در دﻫﻪﻫﺎی اﺧﯿﺮ اﺳﺖ.

Statistical monitoring of dust phenomenon in Khuzestan province with hourly approach

Dust is referred to sediments of less than 100 microns in size which are transmitted as suspended particles. Dust storms are events which naturally occur in arid and semiarid areas, especially in subtropical latitudes. One of the most known sources of dust is the west of Asia, including Arabian Peninsula, Syria, Iraq, and Iran, especially Khuzestan Province. The purpose of this study is to investigate the frequency and trend of dust phenomena on hourly, monthly, seasonal and annual scale between 1995 and 2015 in Khuzestan Province. The method in this study is based on statistical computation of dust parameters and also the trend analysis of data based on MannKendall test and spatial distribution maps of dust phenomena. The results suggests that 78.57 percent of dust event are occurred between 9.30 am to 15.30 pm local time, concurrent with peak of sun radiation and earth surface warming, dryness of soil and local pressure difference. The hourly trend analysis is increasing and significant in all hours and the highest increase occurred at 9.30 pm to 12.30 pm.49 percent of dusty days occurred in June, July and May and also 73 percent of them are in spring and summer as following from temperature increase and water and soil resources drying in the province. The seasonal and annual spatial distribution of dust indicates that most of dusty days in all seasons are located in west of province which suggests dominance of external sources as the main source of dust and the importance of topography factor in this area.The Z value spatial analysis suggests high increase of dust event in recent 20 years in southeast, south and central areas of the province and also on last hours of day which demonstrator development of internal sources activities in increasing trend of dust event in recent decades.