Determination of Wind Chill index based on the climatic data in Iran
Subject Areas : ClimatologySaeed Ranjbar 1 , Gholam Ali Kamali 2 , Hooshmand Ataei 3 , Amir Gandomkar 4
1 - Department of Geography, Najaf abad Branch,Islamic Azad University, Najaf abad, Iran
2 - . Department of Geography, Najaf abad Branch,Islamic Azad University, Najaf abad, Iran
3 - . Associate Professor of Meteorology Department, Islamic Azad University, Science And Research Branch, Tehran, Iran
4 - Associate Professor of PayamnoorUuniversity,Tehran, Iran
Keywords: wind, Minimum temperature, synoptic station, Wind Chill,
Abstract :
آبوهوا تأثیر بسیار مهمی در حیات و گسترش موجودات زنده بر روی کره زمین دارد.Climate is so important for the life and development of the living organisms on Earth. Among all the effects of different atmospheric variables on human comfort, the effect of combined wind and temperature is of particular significance.افت شدید دما همراه با وزش باد،In this study, using statistical data of minimum temperature and wind speed of the synoptic stations during the period 1374 to 1393 ,which were obtained from the Meteorological Organization, the chill wind was zoned in the country.نتایج که از تحلیل داده های 120 تا 314 ایستگاه همدید کشور استفاده شد نشان داد که آبان و فروردین را میتوان به ترتیب بهعنوان ماههای شروع و پایان سوز باد در ایران در نظر گرفت.Results that were obtained from data analysis of 120 to 314 synoptic stations (for different time intervals) showed that we can consider the months of Aban to Farvardin as the start and end of wind chill in Iran, respectively.برای روزهای آبان تا فروردین، میانگین کاهش دمای حداقل بهواسطه وزش باد به میزان 0/4 درجه سلسیوس در ماه بهمن احساس شده است.نقشه های پهنه بندی کشور که برای ماههای سرد سال(ازآبان تا فروردین) ترسیم شد، مشخص نمود که تفاوت بین حداقل دمای هوا و دمای احساسی ( سوزباد) به خوبی معنی دار است.بیشترین فراوانی سوزباد مربوط به سال 1390 با 18069 مورد از 358 ایستگاههای تحت مطالعه و کمترین آن مربوط به سال 1374 با 4322 مورد بوده است.For days of Aban to Farvardin, the average reduction in minimum temperature of 4 degrees Celsius in Bahman due to the wind blowing has been felt.Zoning maps of the country that were traced for the cold months (from Aban to Farvardin), showed that the difference between minimum air temperature and the temperature that can be felt on human body (wind chill) is meaningful as well(Level of significance is in the range of 0.51 to 0.74). The highest frequency of wind chill is related to the year of 1390 with 18088 cases from 330 stations that are under study and the lowest is related to the year of 1374 with 4321 cases.نکته قابل توجه این که هر چه از سال پایه (1374) جلو می رویم فراوانی وقوع سوزباد بیشتر شده و عملاً احساس تعداد روزهای سرد در شهرهای کشور رو به افزایش است.It should be noted that from the base year (1374) onwards ,the frequency of the wind chill occurrence has increased and the numbers of cold days because of the wind existence in the cities of the country are increasing too. by investigating the frequency of wind chill occurrence in the months which are under the study, the month of Bahman with47219 cases from 350 stations and the month of Aban with 17728 cases from 305stations, had the highest and the lowest frequency of occurrence.
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