تحلیل سینوپتیکی بارش‌های سیل آسای فروردین 1398ایران (مطالعه موردی استان لرستان)

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی دکتری تخصصی رشته اقلیم شناسی،واحدعلوم وتحقیقات،دانشگاه آزاد اسلامی،تهران،ایران

2 دانشیار و عضو هیات علمی، دانشگاه آزاد اسلامی، واحد شمال، تهران، ایران

3 استاد و عضو هیات علمی، دانشگاه خوارزمی، تهران، ایران

4 دانشیار و عضو هیات علمی دانشگاه آزاد، واحد اهواز، تهران، ایران

چکیده

در روز 12فروردین 1398وقوع بارندگی شدید و جاری شدن سیل خسارت های بسیاری به استان لرستان وارد کرد. پژوهش حاضر به منظور مطالعه سازوکارهای همدیدی این بارش انجام شده است. ابتدا داده های بارش روزانه ایستگاههای مطالعاتی از هواشناسی دریافت ،در ادامه، داده های سطوح جو: فشار تراز دریا(SLP)، ارتفاع ژئوپتانسیل تراز 850 و 500 هکتوپاسکال، سرعت قائم جو ،جریان باد سطوح 1000، 850 و 500 هکتوپاسکال، رطوبت ویژه تراز 700 هکتوپاسکال و جریان رودباد تراز 250 برای روزهای مطالعاتی از مرکز ملی پیشبینی محیطی آمریکا/مرکز ملی پژوهشهای جوی (NCEP/NCAR) تهیه و نقشه‌ها در نرم افزار گردس رسم و تفسیر شد. نتایج نشان دادکه : روز رخدادسیل یک پر فشار روی شمال اروپا قرار گرفته، پرفشار دیگری پهنه وسیعی از اطراف دریاچه آرال تا شمال شرق افغانستان را دربر گرفته است.همینطور،یک کم فشاری ازمدیترانه تا سراسر پهنه مطالعاتی و در ادامه تا ایران مرکزی وکم فشاردیگری از شمال شرق روسیه با راستای شمال شرق – جنوب غرب تا دریای سرخ و شرق آفریقا را در برگرفته است شیو فشاری شدیدی به وجود آمده است . در تراز 500 هکتوپاسکال، هسته مرکزی برابر با 5540 ژئوپتانسیل متر در راستای شمال شرق- جنوب غرب برروی شرق دریای مدیترانه قرار گرفته و در مقایسه با روز قبل، ناوه عمیق تر و گسترده تر شده است و تا غرب ایران را هسته مرکزی ناوه در برگرفته است. قسمت تاوایی مثبت آن سراسر پهنه مطالعاتی را دربرگرفته و باعث ایجاد حرکات صعودی شده است. بیشینه رطوبت ویژه برابر با 10 گرم در کیلوگرم در شرق آفریقا قرار گرفته و با عبور از دریای سرخ و عرب و در ادامه با عبور از خلیج فارس وارد منطقه مطالعاتی شده است. بنابراین منابع رطوبت بارش سنگین روز 12 فروردین، دریای سرخ، دریای مدیترانه دریای عرب و خلیج فارس است..

کلمات کلیدی: بارش سنگین، ژئوپتانسیل، امگا، همدید، لرستان

کلیدواژه‌ها


عنوان مقاله [English]

Synoptic analysis of Iran 2019 torrential rains (Case study: Lorestan)

نویسندگان [English]

  • Rasool nooriara 1
  • seyed jamalodin daryabari 2
  • bohlol aligani 3
  • Reza borna 4
1 PhD. Student, of Climatology The Islamic Azad University, Science and Research Branch,Tehran, Iran
2 Associate professor,, faculty of Islamic Azad University, North Branch,Tehran, Iran
3 Professor, Kharazmi University, Tehran, Iran
4 Associate professor , faculty of Azad University, Ahvaz branch, Ahvaz, Iran
چکیده [English]

On April 01th , 2019 Iranian calendar, heady damages was inflicted on Lorestan province due to the arising of the heavy rainfall and consequent destructive flood . Present study was carried out to investigate the synoptic mechanisms associated with the occurrence of this rainfall. At first, the data related to the daily rainfall in different research stations was received from the metrological organizations. Afterwards, data related to atmospheric levels including Sea Level Pressure (SLP), the altitude geopotential of 850 and 500 hectopascal levels, vertical atmosphere speed , wind stream in 1000, 850, and 500 hectopascal, specific humidity of 700 hectopascal level , and the river flow of the 250 hectopascal level during the studied days were prepared and received from National Center of the Environmental Prediction (NCEP) and National Center for Atmospheric Research(NCAR). The created maps were drawn and interpreted in Grads Software.

The results of the study indicated that, on April 01th when the flood hit the region, synoptic investigation of the Sea Level Press (SLP) shows a low-pressure system with a central core equals to 1206 hectopascal is located in Northern Europe with its braces covered the north of the Black Sea. Furthermore, the low-pressure system having central core of 1026 hectopascal covered wide regions surrounding Aral lake to North-east of Afghanistan. Accordingly, a low-pressure system having central core of 1008 hectopascal moved to eastern parts compared to previous day and dominated wide regions from Mediterranean through all investigated areas to Central Iran. Given that low pressure system spreads north-east Russia in line with northeast-southwest through Red Sea and East Africa, a high-pressure shave was created which was accompanied by instability and intense ascending of the weather on desired April 01th along with the arising of the rainfall in investigated region. Consequently, with the rise in the altitude and in 850 hectopascal level, low pressure system having central core equaling to 1300 hectopascal dominates North-Russia through lower latitudes. Subsequently, lower altitude closed system corresponding to 1420 geopotential meters resides Eastern Mediterranean and, compared to previous day headed eastwards and spread West and North-west of Iran including investigated region in the north-south direction.

Moreover, high altitude system with central core which equals 1520 geopotential meters has spread North Europe up to 48-degree latitudes, which, given to high altitude system located on Afghanistan and Pakistan, a more intense shave arose compared to previous day. Afterwards, at 500 hectopascal level, central core having 5540 geopotential meters places on East-Mediterranean Sea in its Northeast-southwest direction, which resulted in deeper and wider trough so much that central trough spreads west Iran. The placement of its positive vorticity covers wide investigated region and results in ascending motions. The deepening of the cyclone and penetration of trough to the lower latitudes can gives rise to the precipitation of cold weather.

Synoptic investigation of vertical atmospheric speed of 1000 hectopascal level revealed that maximum negative omega equals -0/2 pascal / second that is located on the North-west of Caspian Sea in Northeast-Southwest direction, and, on its movement toward Lorestan, it decreases in its intensity and reaches -0/05 pascal/ sec. Given that the second negative omega equaling to -0/15 pascal/sec is placed on Persian Gulf and omega is negative throughout the investigated region, the required conditions are really for the occurrence of instability, ascending of the weather, and rainfall. Subsequently, with the rise of altitude in the atmospheric levels, the maximum negative omega has increased and reached 0/3 pascal/sec. Within 500 hectopascal, the direction of negative omega changed from Red Sea towards investigated region which, accordingly, has been strengthened over Caspian Sea and spread the intended region in North-South direction. Given the increasing altitude of the level of the atmosphere, the maximum omega has risen and reached -0/4 pascal/sec, which accordingly intensified the conditions for atmospheric instability.

Synoptic investigation of specific humidity indicated that most of the humidity advection happened from the Southern water reserves to the investigated regions. Maximum humidity core is 24 g/kgs over Red Sea and is decreasing in extent toward Iran, which, subsequently, passed over Persian Gulf and reached 18 g/kgs in Oman Sea and spread intended area in Northwest-Southeast direction.

Humidity injection, particularly from southern water reserves, led to arising of the heavy rainfall during the specified day in investigated region. With the rise in the altitude at the level of 700 hectopascal, maximum specific humidity, which equal 10g/kgs, residing in East Africa and got the investigated region having passed over Caspian Sea. So , the sources for the heavy cloud rainfall on Farvardin 12th are Red Sea, Mediterranean Sea, Arab Sea, and Persian Gulf.





Key Words: Heavy rainfall, Geopotential, Omega, Synopsis, Lorestan.

کلیدواژه‌ها [English]

  • : Heavy rainfall
  • Geopotential
  • Omega
  • synoptic
  • Lorestan
  1. Ahmadi, Mahmoud., Farzaneh Jafari, 2014. Analysis of super heavy rain on March 23, 2012 causing destructive flood in Bandar Abbas city. Risk Science, 2(3): 307-324
  2. Omidhar, Kamal., Mahmoudabadi, Mehdi, Parisa Shams., Mehbobeh Amiri-Esfandgeh, 2019. Collaborative study of the effects of wind movements on floods in Kerman province. Scientific Journal System, 7(3), 163-178
  3. Pejoh, Farshad, Farzaneh Jafari, 2019. Collaborative analysis of heavy and dangerous rainfall in the west and southwest of Iran in the first decade of Farvardin, period 29, number 114 - serial number 114, pages 165-184.
  4. Jahanbakhsh, Saeed., Hassan Zulfaqari, 2013. Review of synoptic patterns of daily rainfall in western Iran, Geographical Research Quarterly, Vol. 64-63, pp. 234-258.
  5. Hosseini Sadr, Atefa, Gholam Hossein. Mohammadi, Firoz, Abdul Alizadeh, Vahid Khojaste, and. 2018. Analyzing the synergistic mechanism of heavy and damaging rain in northwest Iran (case study: April 14, 2017), Journal of Geography and Planning, Volume 23, Number 70 - Serial Number 23, Pages 79-100.
  6. Halabian, Amirhossein., Nikandish, Nasreen, Mehri Akbari, 2018. Complete routing and synoptic analysis of a study sample of systems leading to heavy rains of more than 50 mm in southern Iran, Spatial Analysis of Environmental Hazards, 5th year, Fall 2018, no. 3.
  7. Hamidianpour, Mohsen, Sadeghi, Alireza, Bahlol Alijani, 2009, Identifying synoptic patterns of heavy rains in northeastern Iran, Geographical Studies of Dry Areas, Vol. 1, pp. 1-16.
  8. Zakizadeh Amaslan Alia, Mir Behrouz, Mohammad Saligha, Mohammad Hossein Naserzadeh, Mehri Akbari. 2017. Statistical and synoptic analysis of the most effective river pattern causing heavy rains. Natural Environment Hazards, 7(15): 31-48.
  9. Rastgo, Zahra Abbas Ranjbarsaadabadi, 2017. Study of heavy and moderate rainfall in Bushehr province from synoptic-dynamic point of view, Journal of Meteorology and Atmospheric Science, Volume 1, Number 1, 77-96.
  10. Rezaei, Majid B., Jafarishandi, Fatemeh, Fershte Hossein Alipour Jezi, 2019. Synoptic analysis of pressure patterns related to blockings affecting the occurrence of continuous and heavy rains in Tabriz (during the years 1951 to 2013). Scientific Journal of Geography and Planning, 24(71), 105-123.
  11. Sabzi Parvar, Ali Akbar 1370. Synoptic survey of flood systems in southwest Iran. Master's Thesis in Geophysics, University of Tehran, Iran. P. 105.
  12. Shah-Hosseini, Mansour 2017, evaluation of the effects of drought on agricultural products of Zahedan city, Master's thesis under the guidance of Dr. Hossein Nagaresh, University of Sistan and Baluchistan.
  13. Safrian Zangir, Vahid., Zinali, Betul., Jafarzadeh Aliabad, Leila. 2018. Evaluation of the concurrent conditions of occurrence of rains leading to floods in Khalkhal city, with an environmental approach to circulation in the time period 2016 to 2015, period 10, number 19 - serial number 19, pages 104-89.
  14. Alijani, Bahloul., Mahmoud Hoshiar, 2017. Identification of synoptic patterns of extreme cold in the northwestern region of Iran, Tehran University Geographical Research Journal; pp. 1-16: 65
  15. Alizadeh, Amin, Kamali, Gholamali, Mousavi, Farhad., Mohammad Mousavi Baygi, 2005. Weather and Climatology, 11th edition, Ferdowsi University of Mashhad Press.
  16. Alizadeh, Timur 2009. Synoptic analysis of heavy rains in Kerman province, master's thesis of Isfahan University, supervisor Khushal Dastjardi.
  17. Qaemi, Hoshang, Mirian, Mina., Mostafa Karampour, Mohammad Moradi, 2019. Understanding the dynamic and thermodynamic patterns of widespread heavy rainfall in Iran in the period of 1960-2010 (case study of widespread heavy rainfall 05/12/1974), natural geography researches Bahar Volume 52, Number 1 (consecutive 111) 95-111.
  18. Lashkari, Hossein., Neda Esfandiari, 2019. Synoptic and thermodynamic patterns of atmospheric rivers leading to heavy rainfall in the cold period of Iran, Journal of Natural Environmental Hazards, pp. 1-1.
  19. Mahmoodabadi, Mahdi., Kamal., Umidred, Gholamali, Mozafari, Ahmed, Noosesi, Mehdi., Narangifard Mehran, Fatemi. 2015. Synoptic analysis of the effects of the blocking phenomenon on the flooding rains of April 2012 in the southern half of Iran. Climatology Research, 7(25): 67-82.
  20. Moradi, Hamidreza. 139. Forecasting the occurrence of floods based on synoptic conditions in the southern coast of the Caspian Sea, Geographical Researches, Vol. 55, pp. 109-131.
  21. Mostafaei, Hassan., Bahlol Alijani, Mohammad Saseh, 2014. Synoptic analysis of heavy and widespread rains in Iran. Spatial Analysis of Environmental Hazards, 2(4): 65-76.
  22. Nazim Al-Sadat Mohammad Jaafar, Shirwani Amin, 2016, forecasting winter rainfall in the southern regions of Iran using the water level temperature of the Persian Gulf: conventional correlation analysis modeling, Scientific Journal of Agriculture 29: 66.
  23. Hashmi Rana, S. K, 1389. Collaborative analysis of heavy rains in Khuzestan province, master's thesis of Isfahan University, supervisor: Javad Khushal Dastjard.Ai, Yang, & Qian, Weihong. (2020). Anomaly-based synoptic analysis on the Heavy Rain Event of July 2018 in Japan. Natural Hazards, 101(3), 651-668.
  24. Dimitrova, T, Mitzvahs, R., Savtchenko, A. (2009), “Environmental Conditions Responsible for the Type of Precipitation in Summer Convective Storms over Bulgaria”, Atmospheric Research, pp: 30-38.
  25. Hermoso, Alejandro,Victor Homar., & Amengual, Arnau. (2021). The sequence of heavy precipitation and flash flooding of 12 and 13 September 2019 in eastern Spain. Part I: Mesoscale diagnostic and sensitivity analysis of precipitation. Journal of Hydrometeorology.
  26. Lavers, Divid. A., andGAbriel Villarini, G., 2013, Atmospheric rivers and flooding over the central united states: Journal of Climate, 26, 7836-7829.
  27. Meseguer-Ruiz, Oliver., Lopez-Bustins, Jan. A., Arbiol-Roca, Laia., Martin-Vide, Janier., Miró, J., & Estrela, M. J. (2021). Temporal changes in extreme precipitation and exposure of tourism in Eastern and South-Eastern Spain. Theoretical and Applied Climatology, 1-12
  28. Pall, P., Patricola, C. M., Wehner, M. F., Stone, D. A., Paciorek, C.J., & Collins, W. D. (2017). Diagnosing conditional anthropogenic contributions to heavy Colorado rainfall in September 2013. Weather and Climate Extremes, 17, 1-6.
  29. Paredes Trejo, F. Barbosa, H. Murillo, P. Moreno,A.Farias,A.(2016), Intercomparison of improved satellite rainfall estimation with chirps gridded product and raingauge data over Venezuela, atmosfers, Vol. 29, lssue 4.
  30. Schreiber, E. A., & Serreze, M. C. (2020). Impacts of synoptic-scale cyclones on Arctic sea-ice concentration: a systematic analysis. Annals of Glaciology, 61(82), 139-153.
  31. Uriano, Z.J., Leathers, D.J., & Benjamin, A.E. (2020). Regionalization of Northeast US moisture conditions: analysis of synoptic-scale atmospheric drivers. Climate Research, 79(3), 193-206.
  32. Yao, S. Huang, Q. (2016), An analysis of extreme intraseasonal rainfall events during janury-march 2010 over eastern china, dynamics of atmospheres and oceans, Vol. 75: 22-32.
  33. Zhong, S., Yu, L., Heilman, W. E., Bian, X., & Fromm, H. (2020). Synoptic weather patterns for large wildfires in the northwestern United States—a climatological analysis using three classification methods. Theoretical and Applied Climatology, 141, 1057-1073.