بررسی همدیدی موج گرمای آوریل 2008 ایران

در اﯾﻦ ﺗﺤﻘﯿﻖ ﺑﻪ ﺷﻨﺎﺳﺎﯾﯽ و ﻋﻠﺖ وﻗﻮع ﻣﻮج ﮔﺮﻣﺎی آورﯾﻞ 2008 ﺑﻪ ﻋﻨﻮان ﯾﮑﯽ از ﻓﺮاﮔﯿﺮﺗﺮﯾﻦ اﻣﻮاج ﮔﺮﻣﺎﯾﯽ در اﯾﺮان ﭘﺮداﺧﺘﻪ ﻣﯽﺷﻮد. ﺑﻪ دﻟﯿﻞ اﯾﻨﮑﻪ ﺷﻨﺎﺧﺖ ﻋﻤﯿﻖ ﭼﻨﯿﻦ ﭘﺪﯾﺪهﻫﺎﯾﯽ ﻓﻘﻂ ﺑﺎ اﺳﺘﻔﺎده از دادهﻫﺎی زﻣﯿﻨﯽ اﻣﮑﺎنﭘﺬﯾﺮ ﻧﯿﺴﺖ، ﺑﺮرﺳﯽ ﺷﺮاﯾﻂ ﻫﻤﺪﯾﺪی و ﻋﻮاﻣﻞ ﻣﺆﺛﺮ ﺟﻮی ﺑﯿﺶ از ﭘﯿﺶ ﺿﺮوری اﺳﺖ ﺑﺮای ﻣﻄﺎﻟﻌﻪ ﻫﻤﺪﯾﺪی ﭼﮕﻮﻧﮕﯽ رﺧﺪاد ﻣﻮج ﮔﺮﻣﺎی ﻣﻮرد ﻧﻈﺮ، دادهﻫﺎی ﺑﺎزﺗﺤﻠﯿﻞ ارﺗ ﻔﺎع ژﺋﻮﭘﺘﺎﻧﺴﯿﻠﯽ، ﻓﺸﺎر ﺳﻄﺢ درﯾﺎ، دﻣﺎی ﻫﻮا و ﻫﻤﭽﻨﯿﻦ ﻣﺆﻟ ﻔﻪ ﻧﺼﻒاﻟﻨﻬﺎری و ﻣﺪاری ﺑﺎد در ﺳﻄﻮح ﻣﺨﺘﻠﻒ ﺑﺎ ﺗﻔﮑﯿﮏ 2/5 در 2/5 درﺟﻪ درﯾﺎﻓﺖ ﺷﺪ و درﮔﺎم ﺑﻌﺪ، ﻧﻘ ﺸﻪﻫﺎی ﻣﯿﺎﻧﮕﯿﻦ و آﻧﻮﻣﺎﻟﯽ ﻓ ﺸﺎر و ارﺗﻔﺎع ژﺋﻮﭘﺘﺎﻧ ﺴﯿﻠﯽ در ﺗﺮازﻫﺎی ﻣﺨﺘﻠﻒ، ﻓﺮارﻓﺖ ﻫﻮای ﮔﺮم و ﻧﻘﺸﻪی ﺿﺨﺎﻣﺖ ﺑﺎ اﺳﺘﻔﺎده از ﻧﺮماﻓﺰار grads رﺳﻢ ﺷﺪ. ﻧﺘﺎﯾﺞ ﺑﺮرﺳﯽ ﻫﻤﺪﯾﺪی ﻧﺸﺎن داد ﮐﻪ وﺟﻮد ﮐﻢﻓﺸﺎر ﮔﺮﻣﺎﯾﯽ در ﺳﻄﺢ زﻣﯿﻦ و اﺳﺘﻘﺮار ﭘﺮﻓﺸﺎر ﺟﻨﺐ ﺣﺎره ﻋﺎﻣﻞ اﺻﻠﯽ اﯾﻦ ﻣﻮج ﮔﺮﻣﺎ ﺑﻮده اﺳﺖ. ﺷﮑﻞﮔﯿﺮی ﻣﺮﮐﺰ ﮐﻢﻓﺸﺎر ﮔﺮﻣﺎﯾﯽ در ﺗﺮاز ﭘﺎﯾﯿﻨﯽ ﺟﻮ روی ﺳﻮدان و ﮔﺴﺘﺮش زﺑﺎﻧﻪﻫﺎی آن از ﺳﻤﺖ ﺟﻨﻮب و ﺟﻨﻮب ﻏﺮﺑﯽ روی اﯾﺮان، ﺑﺎﻋﺚ ﻣﮑﺶ ﻫﻮای ﮔﺮم و ﺧﺸﮏ ﻣﻨﺎﻃﻖ ﺑﯿﺎﺑﺎﻧﯽ ﻣﺎﻧﻨﺪ ﻋﺮﺑﺴﺘﺎن و ﻋﺮاق ﺑﻪ ﺳﻤﺖ اﯾﺮان ﻣﯽﺷﻮد. از ﻃﺮﻓﯽ ﭘﺮﻓﺸﺎر ﺟﻨﺐ ﺣﺎره ﮐﻪ از ﻧﻮع ﻫﺴﺘﻪ ﮔﺮم اﺳﺖ، وﻗﺘﯽ در ﺳﻄﻮح ﻣﯿﺎﻧﯽ وردﺳﭙﻬﺮ ﺷﮑﻞ ﻣﯽﮔﯿﺮد ﺑﺮ اﺛﺮ ﻓﺮوﻧﺸﯿﻨﯽ ﻫﻮا در داﺧﻞ آن، دﻣﺎ ﺑﻪ ﻣﻘﺪار زﯾﺎدی اﻓﺰاﯾﺶ ﻣﯽﯾﺎﺑﺪ. در ﻧﺘﯿﺠﻪ اﯾﻦ ﺷﺮاﯾﻂ اﻧﺒﺎﺷﺖ ﮔﺮﻣﺎ ﺷﮑﻞ ﻣﯽﮔﯿﺮد و ﺗﺪاوم آن ﺑﺮای ﭼﻨﺪ روز ﻣﻮﺟﺐ ﺷﮑﻞﮔﯿﺮی ﻣﻮج ﮔﺮﻣﺎی ﻃﻮﻻﻧﯽ ﻣﺪت ﺑﺎ دﻣﺎی زﯾﺎد ﻣﯽ ﺷﻮد. ﺑﺮ ا ﺳﺎس ﺑﺮر ﺳﯽآﻣﺎری ﭘﺪﯾﺪه ﻣﺬﮐﻮر، روز 27 آورﯾﻞ ﺑﻪ ﻋﻨﻮان روز اوج و روزﻫﺎی 26 و 27 ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﺎ دﻣﺎﻫﺎی 32,17 و 32,09 درﺟﻪ ﺳﻠ ﺴﯿﻮس ﺑﻪ ﻋﻨﻮان ﮔﺮمﺗﺮﯾﻦ و روز 22 آورﯾﻞ 2008 ﺑﺎ دﻣﺎی 27,01 درﺟﻪ ﺳﻠﺴﯿﻮس ﺑﻪ ﻋﻨﻮان ﺧﻨﮏﺗﺮﯾﻦ روز ﺷﻨﺎﺧﺘﻪ ﺷﺪﻧﺪ. ﻃﯽ اﯾﻦ دوره ﮔﺮﻣﺎﯾﯽ، آﺳﺘﺎﻧﻪ دﻣﺎﯾﯽ در ﻣﻨﺎﻃﻖ ﻣﺨﺘﻠﻒ ﮐﺸﻮر از16 ﺗﺎ 41 درﺟﻪ ﺳﻠﺴﯿﻮس ﻣﺘﻐﯿﺮ ﺑﻮده و ﺑﯿﺸﺘﺮﯾﻦ ﻣﺴﺎﺣﺖ ﮐﺸﻮر دارای آﺳﺘﺎﻧﻪ دﻣﺎﯾﯽ ﺑﯿﻦ 36 – 31 و 41- 36 درﺟﻪ ﺳﻠﺴﯿﻮس ﺑﻮده اﺳﺖ

Investigating the Synoptic of Heat Wave in Iran in April 2008

In this research, we attempted to identify the cause for occurrence of the heat wave in April 2008 as one of the most significant and most comprehensive heat waves. Since deep recognition of such phenomena is not possible only by ground data, so, it is necessary to study synoptic conditions and effective atmospheric factors more than before. To study synoptic of how the heat wave occurs, the geopotential height, sea level pressure, air temperature, as well as the meridian and orbital component of the wind data at various levels with a resolution of 2.5 to 2.5 degrees, were obtained and the mean maps and anomalies of geopotential pressure and height at different levels, hot air flow and thickness map were plotted using GrADS software. The synoptic results showed that the existence of thermal low pressure in sea level and settlement of the subtropical high pressure was a major cause of this heat wave. The formation of a thermal low pressure center in the lower level of the atmosphere, on Sudan and the expansion from the south and southwest on Iran, causes the hot and dry weather of the desert areas, such as Saudi Arabia and Iraq move towards Iran. On the other hand the subtropical high pressure with hot core, when formed at the intermediate levels of the troposphere, causes a considerable increase in temperature due to air subsidence inside it.