نوع مقاله : مقاله علمی پژوهشی

نویسندگان

• مهدی نارنگی فرد ¹
• مهران فاطمی ²
• عبدالعلی کمانه ³
• محمدصادق طالبی ²

¹ دکترای آب و هواشناسی دانشگاه یزد

² استادیار گروه جغرافیا دانشگاه میبد

³ استادیار گروه جغرافیا طبیعی، دانشگاه آزاد اسلامی واحد شیراز، ایران

چکیده

هدف از این پژوهش بررسی ساختار مقاطع مختلف زمانی بارش در ایستگاه همدید شیراز برای شناخت تغییرات و تعیین موقعیت فضایی ساختار بارش در بازه پایداری و ناپایداری، بوده است. در این راستا ساختار حاکم بر فراسنج آب و هوایی بارش در بازه زمانی 58 ساله (1956-2013) در مقاطع سه گانه زمانی مختلف (سه دوره 20 ساله) بارش روزانه با رویکرد فراکتالی مورد واکاوی و بررسی جداگانه قرار گرفت. برای انجام این پژوهش پس از هم مرجع سازی ریاضی فراسنج بارش با اعمال ساختار مثلثاتی فراکتالی بر روی داده­های بدست آمده به مقایسه نتایج حاصله با هندسه کلاسیک فراکتالی پرداخته شد. بر اساس یافته­های این پژوهش، در مقطع زمانی نخست از 1 ژانویه سال 1956 تا 7065 روز پس از آن با اعمال ساختارهای جبری فراکتالی، نشان داد که این مقطع زمانی از منطق فراکتالی پیروی نمی­نماید. همچنین در مقطع زمانی دوم نیز همانند بازه نخست ساختار بارش از منطق فراکتالی پیروی نمی­کند. به بیان دیگر منطق حاکم بر ساختار فراسنج بارش در مقاطع زمانی نخست و دوم از حالت تعادل به ناتعادلی است. اما برخلاف دو بازه زمانی گذشته، در بازه زمانی سوم، از منطق فراکتالی پیروی می­نماید، که این یافته بیانگر گذار دینامیک این مقطع زمانی از حالت ناتعادلی به عدم تعادل می­باشد؛ بنابراین با توجه به سه بازه زمانی دینامیک تعادلی ساختار بارش روزانه از آشوب به سمت فراکتال میل می­ کند.

کلیدواژه‌ها

• شیراز
• آشوب
• برخال
• تعادل
• بارش

موضوعات

• آب و هواشناسی

عنوان مقاله [English]

Detection of Daily Precipitation Structure in Shiraz Synoptic Station

نویسندگان [English]

• mahdi narangifard ¹
• mehran fatemi ²
• abdolali kamaneh ³
• mohammad sadegh talebi ²

¹ yazduniversity

² Assistant Professor, University of Maybod

³ Assistant Prof. Physical Geography, Islamic Azad University of Shiraz, Shiraz, Iran

چکیده [English]

Introduction
Recently, issues raised by changes in precipitation, especially problems brought about by floods and droughts, along with the environmental effects of diminished rainfall, have underscored the importance of precipitation studies at different temporal and spatial scales. Due to the pervasive impact of precipitation parameter in various urban, industrial and agricultural fields with respect to water supply, the identification of fluctuations, changes and precipitation structure is of particular importance, especially in arid and semi-arid regions. The similarity feature in climatic variables allows the use of fractal geometry and analysis of temporal and spatial changes. Accordingly, the use of fractal geometry in predicting the behavior of many natural processes, including precipitation in different regions, has a special place. The goal of this study is to investigate the structure of different time periods of precipitation in Shiraz synoptic stations to explore changes and determine the spatial position of precipitation in the stability and instability period.
 
 Methodology
In this study, daily precipitation data was received over a period of 58 years (1956-2013) from the Meteorological Organization of Fars Province to investigate the structure governing precipitation parameter. Then, statistical deficiencies were corrected by restructuring using difference ratio and linear regression. The methodology and algebraic logic of calculations in this study are such that in the first step, research parameters are arranged from minimum to maximum in an ascending order. Then, based on the triangular threshold coordinates(2Π), the minimum and maximum were extracted based on linear structures of the desired criteria and algebraic mathematical reference was conducted using Relation (1).
Relation (1)  F (x) =   
Then, in order to apply the fractal structure by applying the criterion for mathematical reference using Relation (2), the real structure of the desired meteorological parameters was obtained.
Relation (2) Y = m² × sin (1/m)                     
Finally, by overlapping the output charts of the actual structures and the classical structure of the fractal (Figure 2) in the algebraic ranges of -0.4 to +0.4, the algebraic process of each climatic parameter was evaluated separately.
 Results and discussion
In this study, based on the results, in addition to the daily analysis of the governing structure of precipitation over a 58-year period (1956-2012), which covered 21185 days, the governing structure along with the analysis of equilibrium dynamics of structures and its functions in three time periods (three 20-year periods) of different daily precipitation were also examined separately.
The first period began in January 1, 1956 and lasted for 7065 days. The relevant calculations were performed on the data derived from the first period, which based on the findings of this study, precipitation in Shiraz''s synoptic stations do not follow the fractal logic in the first period by applying fractal algebraic structures,
Also, in the second period, similar to the first one, the precipitation structure does not comply with a particular fractal logic. In other words, the logic governing precipitation parameter during the first and second periods changes from equilibrium to non-equilibrium. However, unlike the previous two periods, the fractal logic is followed in the third period.
 Conclusion
The self-similarity feature in climatic variables allows the use of fractal dimension and analysis of temporal and spatial changes. Accordingly, the use of fractal geometry in predicting the behavior of many natural processes, including precipitation in different regions, has a special place. The goal of this study was to investigate the structure of different periods of precipitation in Shiraz synoptic station to identify changes and determine the spatial position of precipitation structure in the period of stability and instability. The behavior of meteorological parameters in various parts of the world is a function that never follows uniform algebraic structure. Therefore, the analysis of complex systems and changes in nonlinear climate parameters using chaotic, fractal and fuzzy concepts offers a suitable way to understand the equilibrium state and dynamic analyses of climate fractal changes. The results indicate the dynamic transition of this time period from non-equilibrium to equilibrium. Therefore, according to the three time periods, the equilibrium dynamics of the daily precipitation structure approaches fractal structure.

کلیدواژه‌ها [English]

• Shiraz
• Chaos Theory
• balance
• Precipitation