مروری بر تعاریف و روش‌های محاسبه‌ شاخص ضریب دید به آسمان

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی دکتری شهرسازی، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی، تهران، ایران

2 استادیار گروه شهرسازی، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی، تهران، ایران

3 استاد آب و هواشناسی سینوپتیک، دانشکده جغرافیا، دانشگاه خوارزمی، تهران، ایران.

چکیده

شهر به‌عنوان پدیده‌ای چندوجهی دارای ابعاد گوناگونی است. یکی از مهم‌ترین ابعاد شهر که همواره از جستارهای مطرح در طراحی و برنامه‌ریزی شهری بوده، بُعد هندسی شهر است. هندسه شهری و هندسه دره‌های شهری، که با تغییرات ارتفاع، طول و فاصله ساختمان‌ها تعریف می‌شود، تأثیر قابل‌توجهی بر مبادلات انرژی و در نتیجه درجه حرارت مناطق شهری دارد. دگرگونی هندسه شهر، مسائل و مشکلاتی را در پی خواهد داشت. ازجمله این مسائل، تغییرات اقلیمی در مقیاس خرد و میانه است. هندسه شهر به دلیل تأثیراتی که بر اقلیم شهری می‌گذارد، همواره موردتوجه اقلیم‌شناسان بوده است. یکی از پارامترهای مهم این بُعد، شاخص ضریب دید به آسمان(SVF) 1 است. اگرچه اقلیم‌شناسان شهری این شاخص را به‌خوبی می‌شناسند، اما آن‌طور که باید در میان شهرسازان مطرح نشده است. از طرفی به دلیل ارتباطی که این شاخص با دیگر متغیرهای اقلیمی دارد، می‌تواند در تصمیم‌سازی‌های شهری نقش تعیین‌کننده‌ای ایفا کند. ازاین‌رو پژوهش حاضر ضمن بررسی ضرورت توجه به این شاخص، روش‌ها و تکنیک‌های محاسبه این شاخص و در ادامه دسته‌بندی‌های آن را ارائه نموده است. ازاین‌روی هدف این نوشتار، در وهله نخست شناساندن و بررسی انواع این شاخص و سپس بررسی و دسته‌بندی روش‌های گوناگون محاسبه و برآورد آن است. یافته‌های پژوهش نشان می‌دهد که محاسبه و برآورد SVF با روش‌های عکاسی و تحلیلی آغاز و با روش‌های نرم‌افزاری و GPS گسترش روز افزونی پیداکرده است. همچنین در جدول پایانی نوشتار، دسته‌بندی از پیشینه موضوع به همراه روش‌ها و تکنیک‌های گوناگون محاسبه و نرم‌افزارهای وابسته به‌تفصیل نشان داده‌شده است.

کلیدواژه‌ها


عنوان مقاله [English]

A Review of the Definitions and Calculation Methods of Sky View Factor

نویسندگان [English]

  • Abdolhossein ZarifianMehr 1
  • Laala Jahanshahloo 2
  • Bohloul Alijani 3
  • Hossein Zabih 1
1 Ph.D. Candidate of Urban Development, Department of Urban Development, Science and Reasearch Branch, Islamic Azad University, Tehran, Iran.
2 Assistant Professor of Urban Development, Department of Urban Development, Science and Reasearch Branch, Islamic Azad University, Tehran, Iran
3 Professor of Climatology, Faculty of Geography, Kharazmi University, Tehran, Iran
چکیده [English]

The city, as a multifaceted phenomenon, has various dimensions. One of its most important dimensions, which has always been one of the debates raised in urban design and planning, is its geometry. Urban geometry and the geometry of urban valleys, which are defined by changes in height, length, and distance of buildings, significantly affect energy exchanges and thereby the temperature of urban areas. Changes in urban geometry will lead to some problems and issues, one of which is climate change on micro and medium scales. The geometry of the city has always been of interest to climatologists due to its effects on the urban climate. One of the important parameters of it is the Sky View Factor (SVF). Although urban climatologists know this factor well, it has not been properly raised among urban planners. On the other hand, since this factor is related to other climatic variables, it can play a key role in urban decision-making. Therefore, in the present study, it is attempted to present and classify the methods and techniques used for calculating this factor, while examining the need to pay attention to it. Therefore, this study aims to identify and study the types of this factor and then to study and classify various calculation and estimation methods. The results of this study show that the calculation and estimation of SVF have started with photographic and analytical methods and increasingly expanded with software and GPS methods. Also, at the end of this study, a classification of the background of the topic, along with various calculation methods and techniques and related software, is presented in a table in detail.

کلیدواژه‌ها [English]

  • Urban geometry
  • Sky View Factor (SVF)
  • method
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