تحلیل روند شدت بارش سامانه‌های سودانی ورودی به ایران (مطالعه موردی:مسیرهای مستقل ورودی استان‌های خوزستان، بوشهر و هرمزگان)

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی دکترای آب و هواشناسی، واحد علوم و تحقیقات دانشگاه آزاد اسلامی، تهران، ایران

2 دانشیار آب و هواشناسی، دانشکده علوم زمین، گروه جغرافیا، دانشگاه بهشتی، تهران، ایران

3 استاد آب و هواشناسی، دانشکده علوم انسانی، گروه جغرافیا، دانشگاه تربیت مدرس، تهران، ایران

چکیده

هدف پژوهش حاضر، تحلیل روند شدت بارش سامانه‌های سودانی ورودی به ایران، از سه مسیر مستقل استان‌های خوزستان، بوشهر و هرمزگان است. به این منظور ابتدا براساس شاخص‌های مورد نظر(1-ریزش حداقل یک میلی‌متر بارش در50 درصد ایستگاه‌های هر مسیر. 2- حداقل در یکی از ایستگاه‌ها بارش پنج میلی‌متر و بیشتر رخ داده باشد. 3- در ایستگاه نماینده ورود هر مسیر بارش رخ داده باشد و یا از آن‌جا شروع شده باشد.)، و با استفاده از داده‌های بارش روزانه هر مسیر در دوره‌ی 2017-1995، سامانه‌های سودانی استخراج و سپس معدل بارش آن‌ها، به تفکیک سالانه، ماهانه و دوره‌ی تداوم بارش، برای مسیرهای سه گانه استخراج گردید. در نهایت پس از آماده‌سازی و صحت سنجی داده‌های بارش، با استفاده از روش‌های آماری خط بهترین برازش، من-کندال و تخمین‌گر شیب سن، روند و شیب تغییرات شدت، در سطح اطمینان 95 درصد بررسی گردید. نتایج نشان داد که شدت بارش سامانه‌های سودانی(به تفکیک معدل سالانه، ماهانه و دوره‌های‌ تداوم بارش) در مسیرهای سه‌گانه، علی‌رغم وجود شیب تغییرات کاهشی و افزایشی بسیار جزئی((کم‌تر از 0/6± میلی‌متر طی دوره)، فاقد روند و شیب تغییرات قابل توجه و معنی‌داری است که بتوان آن را به تغییرات آب و هوایی نسبت داد. اما در کل بارش سامانه‌های سودانی در منطقه مورد مطالعه عمدتاً کوتاه مدت(دو روزه )و به ندرت بارش‌های آن‌ها در دوره‌های تداوم پنج روز و بیشتر رخ می‌دهد از این رو بارش‌های سامانه سودانی در منطقه مورد مطالعه(جنوب وجنوب‌غرب ایران)، عمدتاً کوتاه مدت و شدید است.

کلیدواژه‌ها


عنوان مقاله [English]

Analysis of precipitation intensity trend of Sudanese systems entering Iran (Case study: Independent entry routes to Khuzestan, Bushehr and Hormozgan provinces)

نویسندگان [English]

  • shapor ghazipor 1
  • Hassan lashkari 2
  • manochehr farajzadeh 3
1 Ph.D. student Science and Research Branch, Azad University, Tehran, Iran
2 Associate Professor, Faculty of Earth Sciences, Department of Geography, ShahidBeheshti University, Tehran, Iran
3 , Professor, Faculty of Humanities, Department of Geography, TarbiatModares University, Tehran,
چکیده [English]

Analysis of precipitation intensity trend of Sudanese systems entering Iran

(Case study: Independent entry routes to Khuzestan, Bushehr and Hormozgan provinces)



Extended Abstract

Introduction:

Rainfall is the most important source of water supply in the south and southwest of Iran. The Sudanese system is the most important cause of rain in these areas, which occurs mainly in the short and severe. Optimal survival is directly and indirectly related to the quantity and quality of these precipitations. As mentioned earlier, one of the most important characteristics of Sudanese systems in the south and southwest of Iran is their intensity. In the study of rainfall regime in the south and southwest of Iran, The lack of study of the intensity of rainfall in Sudanese systems, especially in recent decades, is quite evident. Therefore, in the present study, the trend of rainfall intensity of Sudanese systems from three independent input routes of Khuzestan, Bushehr and Hormozgan, which corresponds to the three main routes (A, B and C) of Lashkari (2002) research, is investigated. To use its findings in the management of water resources and atmospheric events such as floods and droughts.

Research Methods:

In the present study, in order to analyze the trend of rainfall intensity of Sudanese systems in the triple routes of Khuzestan, Bushehr and Hormozgan, first 43 study stations were separated in the form of three routes. In the entrance route of Khuzestan included: 23 stations from the provinces of Khuzestan, Ilam, Kohgiluyeh and Boyer-Ahmad, Chaharmahal and Bakhtiari and Lorestan, in the entrance route of Bushehr included; 15 stations from Bushehr, Fars, Kohgiluyeh and Boyer-Ahmad provinces and at the entrance of Hormozgan, including; 7 stations of the province itself. Then, based on the rainfall incidence index of 1 mm and more in 50% of the stations of each route, the frequency of annual, monthly and continuous rainfall periods of Sudanese systems were identified using daily rainfall data (1995-2017) and then their average rainfall was extracted. Finally, after validating the data, the trend of rainfall intensity in Sudanese systems (2017-1995), using the methods; line of best fit, Man-Kendall and Sen’s slop estimator and based on the annual average, monthly and rainfall continuity periods, at 95% confidence level, it was checked in Visual Basic Excel environment and SPSS software

Results and conclusion:

Sudanese systems operate in the cold period of the year in Iran (from the entrance routes of Khuzestan, Bushehr and Hormozgan). The rainfall of these systems in the triple routes is more 1 to 3 days, and rarely have rainfall of 5 days or more. The study of the trend of rainfall intensity of Sudanese systems (1995-2017) in the triple routes showed; the trend of rainfall intensity of these systems based on the annual average in the triple routes has a slope of decreasing changes of -0.04 to -0.1 mm during the period .However, these trends and the slope of changes are significant only in the rainfall of Bushehr route systems with a slope of very small decreasing changes (-0.1 mm during the period). The trend of rainfall intensity in Sudanese systems based on the monthly average of rainfall in the triple routes, is decreasing in some months and increasing in some. The slope of changes in these trends is in most cases zero and in some cases from 0.55 to -0.58 millimeters during the period, fluctuating. But in the meantime, only the increasing trend of November in Bushehr entrance route (0.55 one mm during the period) and the decreasing trend of February in Khuzestan entrance route (-0.21 mm during the period) is significant. The trend of rainfall intensity of Sudanese systems in the three routes is based on the average rainfall of different periods of continuity, in most cases decreasing and in some cases increasing. The slope of changes in these trends is in most cases zero and in some cases from 0.12 to -0.43 mm during the period. But in the meantime, only the decreasing trend of 2-day systems of Bushehr route with a slope of changes of -0.26 mm during the period is significant.

Conclusion:

Despite the trend and slope of decreasing and increasing changes in the rainfall intensity of Sudanese systems, but due to the lack of significant trends and slope of changes (less than 0.6 ∓ one millimeter during the period), it can be concluded; The rainfall intensity of Sudanese systems in the entrance routes of Khuzestan, Bushehr and Hormozgan, lacks the trend and slope of significant changes at the 95% confidence level. But in general, Sudanese systems in most cases have short and heavy rainfall, and rarely light and long rainfall. As a result, the occurrence of heavy rains caused by Sudanese systems in the entrance routes of Khuzestan, Bushehr and Hormozgan should still be accepted as a principle. Therefore, floods are still one of the most important threats facing the study areas.

Keywords: Trend, precipitation intensity, Sudanese‌‌ Systems, Man-Kendall, Sen,s Estimator, Iran.

کلیدواژه‌ها [English]

  • Trend
  • Precipitation intensity
  • Sudanese Systems
  • Iran
1. Samman, A. E., & Gallus Jr, W. A. (2018). A classification of synoptic patterns inducing heavy precipitation in Saudi Arabia during the period 2000-2014. Atmósfera, 31(1), 47-67.
2. Ansari, S. (2003). Synoptic Investigation of Flooding Systems in Kohgiluyeh Boyer Ahmad Watersheds. Supervisor: Alijani, B. Master, Thesis. Teacher Training University of Tehran.Faculty of Literature and Humanities.  Geography Group. Tehran.
3. Arvin, A., Ghangramah, A., Hajipour, D., Heydari, M. (2016). Investigation The Changes In Some Climate Elements In Chaharmahal Bakhtiari Province. Journal of Applied Research in Geography. (41)13, 153-176.
4. Asakereh, H., Ghaemi, H., & Beyranvand, A. (2015). Trend Analysis of the Recent Seasonal Changes in Subtropical Jet Stream in Climateof Iran. Physical Geography Research Quarterly, 47(1), 57-72.
5. Azarakhshi, M., Farzad Mehr, J., Eslah, M., Sahabi, H. (2013). Investigation of annual and seasonal trends of precipitation and temperature parameters in different climates of Iran. Journal of Range and Watershed Managementو 66(1), 1-16.
6. Babaei Feni, A. Farajzadeh, M. (2002). Patterns of Spatial and Temporal Changes in Precipitation in Iran. Journal of Teacher of Humanities. 6(4), 51-70.
7. Basem Ajjur,S. Riffi, M. I. (2020). Analysis of the observed trends in daily extreme precipitation indices in Gaza Strip during 1974–2016. International Journal of Climatology. Pp: 6189-6200. https://doi.org/10.1002/joc.6576
8. Bayat, A., Sallighah, M., Akbari, M. (2017). Climatology of winter rainy cyclones in Iran. Journal of Spatial Analysis of Environmental Hazards, forth year. No. 2. Tehran. 18-1.
9. Bougara, H. Baba Hamed, K. Borgemeister, C. Tischbein, B. And Kumar, N. (2020). Analyzing Trend and Variability of Rainfall in The Tafna Basin (Northwestern Algeria). Atmosphere, 11(4).347;https://doi.org/10.3390/atmos11040347.
10. Diop L., Bodian A., and Diallo D. (2016). spatiotemporal trend analysis of the mean annual rainfall in Senegal. European scientific journal, vol,12. No,12. Pp:231-245.
11. Duhan, D., and A, Pandy. (2013).Statistical analysis of long term spatial and temporal trends of precipitation during 1901–2002 at Madhya Pradesh, India. Atmospheric Research. No. 122. Pp:136-149.
12. Eddenjal, A. S. (2019). Spatio Temporal Variability of Rainfall Across Western Libya from 1979 to 2009. Current Environmental, 6(3), 235-244.
13. Fatah Nia, Amanullah.(2005). Routing and frequencying of precipitation systems in western Iran in the period (1990-1999). Master Thesis. Trabiat Modares University.
14. Feidas, H., Noulopoulou, Ch. T,  Makrogiannis, T., Bora-Senta, B. (2007). Trend analysis of precipitation time series in Greece and their relationship with circulation using surface and satellite data: 1955–2001. Theor, Appl, Climatol. No. 87. Pp:155–177.
15. Gandmokar, Amir. (2010). Synoptic survey of heavy rainfall in southern areas of Bushehr province. Journal of Geographical Perspectives(Scientific-Research). No,4(10) . Pp:143-157.
16. Ghasab fiz, M,. and H, Aslami. (2017). Evaluation Trend of Rainfall Changes by Mann Kendall and Linear Regression in Khuzestan Province. Journal of Water Engineering. No,5(2). Pp:113-121.
17. Hajjam, S., Y. Khoush Khou, and R. Shams Aldin Vandi .(2008). Annual and seasonal precipitation trend analysis of some selective meteorological stations in centeral region of Iran using non-parametric methods. Geographical  Research Quarterly. No, 40(64). Pp:157-168.
18. Hossaini sayed mohammad .(2018). Analysis of the trend of precipitation in southwest Asia over the last half century. Journal of Applied Research in Geography. No, (94)18. Pp:151-166.
19. Jain, SK., V, Kumar. and M, Saharia. (2013). Analysis of  rainfall and temperature trends in northeast India. International Journal of Climatology. No, 33: Pp:968-978.
20. Javanmaed, S,. I, Babaeian. J, Badagh jamali. And A, Shahabfar. (2003). Investigation the Correlation Between Kazakhstan-Oman Pressure Changes with Iranian Rainfall Fluctuations. Journal of Geographical Research. No, (4)18. Pp:134-150.
21. Jiang, T., B, Su. and H, Hartmann. (2007). Temporal and spatial trends of precipitation and River flow in the Yangtze River basin, 1961-2000. Geomorphology. No, 85. Pp:143-154.
22. Kampata, J.M., B.P,  Parida. & D.B, Moalafhi. (2008). Trend analysis of rainfall in the headstreams of the Zambezi River Basin in Zambia. Physics and Chemistry of the Earth. Vol, 33. Pp: 621–625.
23. Katiraei, P., Hajjam, S., Iran nezhad, P. (2007). Contribution from the variation of precipitation frequency and daily intensity to the precipitation trend in Iran over the period 1960-2001. Journal of the earth and space physics. 33(1), 67-83.
24. Khosravi, Y., Aazami, J. Rajaei, M. Motavali. (2019). Investigating the Trends and Fluctuations of Precipitation in the Golpayegan Salty Wetland.Journal of Environmental Science Studies. 3 (4), 851-861.
25. Lashkari, H. (2002). Routing of Sudanese low pressure system to Iran. Modarres Magazine.  6(2), 133-156.
26. Lashkari, H., Ghaimi, H., Parrak, F., (2013). Analysis of the rainfall regime in the south and southwest of the country. Sepehr Magazine. 22(85), 57-63.
27. Mafakheri, Omid. Muhammad, Salighah. Behlool, Alijani & Mehri, Akbari. (2017). Identification and zoning of temporal changes and precipitation uniformity in Iran, Natural Geography Research. Volume 3. Number 2. Pages 205-191
28. Marofnezhsd, A., Ghasemi S. (2017). The trend of temperature changes, using the Mann-Kendall method (Case study: four cities of Chaharmahal and Bakhtiari province), Environmental Planning Quarterly. 37, 149 -166
29. Masoudian, S. A. (2008). Iran Climatology. Isfahan University press. Pp: 179.
30. Masoudian, S.A., Montazeri, M. (2006). Analysis of climate drought trends of Iranian watersheds in the last half century. Vice Chancellor for Research of water Resources Management Company. Sponsor Vice Chancellor for Research, Isfahan University.
31. Mathbout, S., Lopez-Bustins, J. A., Royé, D., Martin-Vide, J., Bech, J., & Rodrigo, F. S. (2018). Observed changes in daily precipitation extremes at annual timescale over the eastern Mediterranean during 1961–2012. Pure and Applied Geophysics, 175(11), 3875-3890.
32. Merabtene, T., Siddique, M., & Shanableh, A. (2016). Assessment of seasonal and annual rainfall trends and variability in Sharjah City, UAE. Advances in Meteorology, 2016.
33. Mofidi, E., and A, Zarin. (2005). Synoptic Analysis of the Nature of Sudanese’s Low Pressure Systems (Case Study: Hurricane December 2001). Geographical Land Journal. 2(6), 24-48.
35. Mohammadi, B. (2011). Analysis of annual rainfall trend in Iran. Journal of Geography and Environmental Planning, 43(3), 106-95.
36.Mohammadi, H,. Ftahi, E., Shamsipour, A., Akbari, M. (2012). Dynamic analysis of Sudanses systems and the occurrence of heavy rainfall in southwestern Iran. Journal of Applied Research in Geography. 12(24), 7-24.
37. Montazeri, M., Nami, M. H., Dalaii, H. (2013). Synoptic Analysis of heavy rainfall November 21, 2011 Kohgiluyeh Boyer Ahmad Province (Lick). Geographical Land Journal. 10(37), 77-91.
38. Mulugeta, S., Fedler, C., & Ayana, M. (2019). Analysis of long-term trends of annual and seasonal rainfall in the Awash River Basin, Ethiopia. Water, 11(7), 1498.
 39. Omidvar, K., Koushaki, H., Ebrahimi, R., Yadollahi, A. (2015). Synoptic-Dynamic Analysis of Extreme and Rare precipitation, April 9-13, 2007, South and Southwest of Iran. Journal of Climatological Research. 6(23), 79-90.
40. Omidvar, K., Türkes, M., (2013). Identification of heavy rainfall patterns in Chaharmahal Bakhtiari province. Journal of Teacher of Humanities- Space Planning and Preparation. 16(4).135-169.
41. Parrak, F., Roshani. A., Alijani, B. (2015). Synoptic Investigation of Sudanese Low Pressure System in the Occurrence of Wetlands and Droughts in the Southern Sub-Region of Iran. Journal of Geography and Environmental Hazards. (4)15. 75-90.
42. Tabari, H., & Talaee, P. H. (2011). Temporal variability of precipitation over Iran: 1966–2005. Journal of Hydrology, 396(3-4), 313-320. 
43. Gado, T. A., El-Hagrsy, R. M., & Rashwan, I. M. H. (2019). Spatial and temporal rainfall changes in Egypt. Environmental Science and Pollution Research, 26(27), 28228-28242.
44. Wale, V. D., Sthool, V. A., & Upadhye, S. K. Analysis of annual rainfall and rainy days trend using Mann Kendall method and sen’s slope estimator in Sangli District of Maharashtra.
45. Mohammed, Y., Yimer, F., Tadesse, M., & Tesfaye, K. (2018). Variability and trends of rainfall extreme events in north east highlands of Ethiopia. Int J Hydro, 2(5), 594-605.