Journal of Spatial Analysis Environmental Hazards
تحلیل فضایی مخاطرات محیطی
Journal of Spatial Analysis Environmental Hazards
Literature & Humanities
http://jsaeh.khu.ac.ir
1
admin
2423-7892
2588-5146
10.61186/jsaeh
fa
jalali
1393
10
1
gregorian
2015
1
1
1
4
online
1
fulltext
fa
تحلیل آماری و سینوپتیکی کولاک برف در استان آذربایجان غربی
The Statistical and Synoptic Analysis of Snow Storms in Western Azerbaijan Province
تخصصي
Special
پژوهشي
Research
<p dir="RTL" style="text-align: justify;"><span style="font-family:nasimyw;"><strong>هدف این تحقیق تحلیل آماری و سینوپتیکی کولاک برف در استان آذربایجان غربی است. بدین منظور، از سازمان هواشناسی کشور دادههای مربوط به کدهای هوا طی دورهی آماری 1986 تا 2009 اخذ شد. با استفاده از نرمافزار </strong><strong><span dir="LTR">Excel</span></strong><strong> و </strong><strong><span dir="LTR">Spss</span></strong><strong> کدهای مربوط به کولاک برف (کدهای 36 تا 39) مشخص و به بررسی آماری دادهها پرداخته شد. سپس، نقشههای مربوط به فشار، امگا (ناپایداری)، دما و جهت و سرعت باد از سایت </strong><strong><span dir="LTR">cdc.noaa.gov</span></strong><strong> جمعآوری شدند و تحلیل سینوپتیکی آنها صورت گرفت. نتایج تحقیق نشان داد که در طی دورهی آماری مورد مطالعه 322</strong> <strong>روز همراه با کولاک برف بود که سال 1992 دارای بیشترین و سال 1999 دارای کمترین روز همراه با پدیدهی کولاک برف بود. با توجه به اینکه رخداد پدیدهی کولاک برف مربوط به فصل سرد سال است، مطالعهی حاضر نشان داد که ماههای ژانویه و فوریه زمان اوج رخداد پدیدهی کولاک برف هستند. با توجه به شرایط سینوپتیکی حاکم بر منطقه، ارتفاع و عامل توپوگرافی از مهمترین عوامل تأثیرگذار در رخداد پدیدهی کولاک برف بودند. از هفت ایستگاه سینوپتیکی مورد مطالعه، ایستگاه سردشت دارای بیشترین و ایستگاه خوی دارای کمترین روز همراه با پدیدهی کولاک برف بودند. سرانجام، نتایج حاصل از تحلیل سینوپتیکی نشان داد که طی دورهی آماری مورد مطالعه در استان آذربایجانغربی دو الگوی گردشی در رخداد پدیدهی کولاک برف نقش داشتهاند که شامل الگوی گردشی کمفشار دریای خزر ـ پرفشار اروپای شرقی و الگوی کمفشار شمال دریای سیاه است.</strong></span></p>
<p style="text-align: justify;"><span style="font-family:times new roman;">Climate is one of the important natural factors that affect all stages of life, particularly human exploitation. Selection of the type of clothing, housing, cultures, architecture, civil engineering, and settlements are influenced by climatic factors. It can be said that the climatic circumstances of the surface of the earth and atmospheric circulation patterns have an important role in shaping and organizing the environment (Alijani, 2009). In some cases, the normal weather conditions become abnormal and cause many damages, which are mostly catastrophes rooted in climatic changes, such as hail, frost, heat and cold waves, floods, storms and so on. Blizzard is one of the atmospheric phenomena, which happens as the result of snow combined with wind (15 meters per second), and low temperatures (below zero°C), and it causes severe losses.</span></p>
<p style="text-align: justify;"><span style="font-family:times new roman;">Due to its special geographical location, Iran is placed in the transition region of the large-scale patterns of common tropospheric circulation, and is the intersectional place of the of extra-tropical and tropical circulation system. This feature along with its complex topography caused the land to have a considerable climatic diversity. The climatic diversity makes the various climatic phenomena to be observed with intensity, energy, and different frequencies, therefore, the climatic phenomena with high intensity always causes damage to natural resources and the human civilization. This undesirable phenomenon is called climatic risks. Since the West Azerbaijan Province is located in mountainous areas and high latitudes, the feature is triggered many climatic risks such as flood, hail, snow, snow storm, and so on. Therefore, snowstorm is one of such phenomena that have occurred every year or every few years due to the specific characteristics of the region and have caused damages in the fields of transportation, energy, livestock, closeness of schools and offices.</span></p>
<p style="text-align: justify;"><span style="font-family:times new roman;">The purpose of this study is the statistical and synoptic analysis of snowstorm in west Azerbaijan province. Therefore, the data related to the present weather codes were collected during the period 1986 to 2009 from the National Meteorological Agency. The data related to the weather codes entered in Excel, and data related to the snowstorm were selected through Filter tool and isolation of codes related to the strong snowstorms (codes 37and39) and weak snowstorms (codes 36 and 38). Then the data related to the snowstorm was entered in SPSS, and the statistical analysis was performed. In the next step, three cases of the strong and common snowstorm (code 37 and 39) were selected for synoptic analysis. Then, the synoptic maps of the different layers of the atmosphere were selected as the samples for strong snowstorm for the days before the event of the phenomenon, the day of event, and the day after the event of the phenomenon by the using of the accuracy of 2.5 degrees from cdc.noaa.gov website. The study area has been selected in 10 to 80 degrees north latitude, and 15 to 90 degrees east longitude for identifying the patterns that affect West Azerbaijan Province. The data was received on wind speed and direction in digits from the National Center for Environmental Prediction. Then, the maps of the wind direction and speed were provided in Grads. Finally, the daily analysis and interpretation of pressure (500hPa at sea level), instability (700hPa level and the ground level), Earth's surface temperature, wind speed and direction maps for 700hPa level, and identification of patterns that have caused snowstorm in West Azerbaijan province were carried out. Statistical and synoptic analysis of snowstorm phenomenon in West Azerbaijan province during was performed in the period 1986 to 2009. To do this, using codes 36 to 39, which represent a variety of snowstorm (weak and strong), the frequency of snowstorm days on monthly and annual average, distribution of the snowstorm in the extracted stations, the frequency of strong snowstorms (codes 37and39), weak snowstorms (codes 36 and 38), all types of snowstorms (codes 36 to 39), and the frequency of storms in the station level were compared. Out of 322 snowstorms occurred during the period 1986 to 2009 in seven synoptic stations 108 have been determined as strong snowstorm and 214 as weak snowstorm. In order to analyze the synoptic snowstorm in West Azerbaijan province, in the first place, the strong snowstorms were identified, and then five of the strong and comprehensive storms were selected for the synoptic analysis. The snowstorms of choice are as follows: On 18 January 1986, on January 19, 2000, on February 7, 1992, on February 5, 1997, and on December 25, 1990.</span></p>
<p style="text-align: justify;"><span style="font-family:times new roman;">For applying the study, pressure maps, Omega (700hp level at ground level), Earth's surface temperature, and wind speed and direction at 700hPa were analyzed, and patterns and conditions that are causing this phenomenon in the West Azerbaijan province were identified.</span></p>
<p style="text-align: justify;"><span style="font-family:times new roman;"> In this study, to perform statistical and synoptic analysis of snowstorm in Western Azerbaijan province, the statistical data were examined during the period 1986 to 2009 from 7 stations, and the results of the statistical analysis showed that:</span></p>
<p style="text-align: justify;"><span style="font-family:times new roman;">• Out of a total 322 snowstorm event days of 7 synoptic stations during the period 1986 to 2009, 108 and 214 days were strong and weak snowstorms, respectively.</span></p>
<p style="text-align: justify;"><span style="font-family:times new roman;">• Review the annual and monthly snowstorm during the study period showed that the 1992, 1997, and 1989 with a total of 69, 29, and 25 days, as well as the 1999, 2006 and 2007 with 0, 1, and 1 day have the most and the fewest days of snowstorm, respectively. The statistical analysis showed that the snowstorm phenomena happened in January, February, March, April, November, and December. January had the most and April had the fewest snowstorms with 119 and 3 days, respectively. February with 39 days, and April and November, with the number 0 and 1 had the most and the fewest days of strong and constant snowstorms.</span></p>
<p style="text-align: justify;"><span style="font-family:times new roman;">• Distribution of the snowstorms in the stations indicated that out of the studied seven synoptic stations, which had a great impact on the synoptic situation of the region, topography, and height, Sardasht-Maku station had the most, and stations of Khoy, Mahabad, and Orumiyeh by having no snowstorms had the fewest days of snowstorm.</span></p>
<p style="text-align: justify;"><span style="font-family:times new roman;">• The results of the maps of the different levels of the atmosphere and Earth’s surface in the days before the storm, event day and the day after the snowstorm were selected for the snowstorm pattern, which indicated that the snowstorm in the winter due to low compliance pressure formed in the earth's surface with synoptic patterns of middle levels of the atmosphere have provided the conditions for the event, in a way that among the sample cases of the strong snowstorms occurred in the West Azerbaijan Province two circulation patterns were involved in the formation of natural hazards: The Caspian Sea low pressure pattern- Eastern Europe high pressure pattern and the north of the Black Sea low pressure pattern.</span></p>
کولاک برف, فشار, تحلیل آماری, تحلیل سینوپتیکی, استان آذربایجانغربی.
Snow Storm, Pressure, Statistical Analysis, Synoptic Analysis, Western Azarbaijan Province.
75
90
http://jsaeh.khu.ac.ir/browse.php?a_code=A-10-1-29&slc_lang=fa&sid=1
Bohloul
Alijani
بهلول
علیجانی
bralijani@gmail.com
1003194753284600687
1003194753284600687
Yes
دانشگاه خوارزمی
Bahram
molazadeh
بهرام
ملازاده
1003194753284600688
1003194753284600688
No
دانشگاه خوارزمی
Mohammad
saligheh
محمد
سلیقه
1003194753284600689
1003194753284600689
No
دانشگاه خوارزمی
Mohammad Hossein
Nassrzadeh
محمدحسین
ناصرزاده
1003194753284600690
1003194753284600690
No
دانشگاه خوارزمی