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Study of Wind Chill Index and its Relation with Siberian High Pressure in Adjacent Provinces of Alborz Mountains
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Sahar Ghiasi Ghorveh1   , Firouz Mojarrad * 1, Samira Koshki1 |
| 1- Razi University |
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Abstract: (1102 Views) |
| Wind chill is the feeling of a colder temperature due to the loss of heat through the wind. This phenomenon has important effects on human life, especially in the cold period of the year, and is highly dependent on atmospheric pressure patterns that cause changes in air temperature and wind speed. The present study investigates wind chill and the effect of Siberian high pressure on it in the neighboring provinces of Alborz mountain range. For this purpose, first daily temperature and wind data of 13 synoptic stations adjacent to Alborz mountain range in a period of 31 years (1986-2016) were obtained from the Iranian Meteorological Organization. Then the Wind Chill Index (WCI) in the stations was calculated daily. To investigate the effect of Siberian high pressure on wind chill, 30 sample events were selected and analyzed. For this purpose, NCEP/NCAR data including sea level pressure, geopotential heights of 500, 700, 925 hPa, vector wind of 700 hPa and temperature of 700 hPa were used and the relevant maps were prepared using GrADS software. The results showed that in the southern stations of Alborz mountain range, wind chill occurs with more frequency and intensity. Qazvin and Abali stations in the south with the annual average of 16 and 15 days, respectively, have the highest and Babolsar and Anzali stations in the north with the annual average of 0.58 and 1.1 days, respectively, have the lowest frequency of wind chills. The highest number of days with more severe wind chills (WCI less than -10) also occurred in Abali and Qazvin stations (5.39 and 3.65 days per year, respectively), while the northern stations have basically not experienced more severe wind chills. On a monthly basis, the highest frequency of occurrence of the phenomenon is related to January and February. Combining station data with pressure data showed that out of the 30 selected events, Siberian high pressure was the cause of wind chill occurrence in only 4 events. In the rest of the studied events, factors such as trough formation, high pressure penetration from the Mediterranean and Black Seas, or a combination of factors (Siberian high pressure, trough formation and migratory high pressure) caused wind chills. But the role of trough has been more important. |
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| Keywords: Wind Chill, Temporal-Spatial Changes, Siberian High Pressure, Alborz Mountain Range |
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Full-Text [PDF 2444 kb]
(237 Downloads)
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Type of Study: Research |
Subject:
Special
Received: 2021/09/29 | Accepted: 2022/06/30 | Published: 2023/01/30
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