نقش تغییرات کاربری اراضی بر شکل گیری دمای سطح زمین در شهرها، مطالعه موردی: شهر اصفهان (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
گسترش و توسعه شهرها و افزایش شهرنشینی یکی از ویژگی های کنونی و عصر حاضر جوامع انسانی به ویژه کشورهای درحال توسعه است. تراکم و ازدیاد جمعیت در شهرها منجر به گسترش و توسعه نواحی شهری و تغییر در کاربری اراضی شهری گردیده است. در این تحقیق با استفاده از تکنیک سنجش ازدور نسبت به شناخت الگوها و بررسی تغییرات مکانی دمای سطح زمین در مناطق مختلف شهر اصفهان اقدام شد. با استفاده از معادلات حرارتی و الگوریتم مرکز مشابهت، دمای سطح زمین برای دوره های 1365 تا 1401 محاسبه گردیده است. برای ارزیابی تغییرات صورت گرفته در کاربری اراضی محدوده موردمطالعه که شامل کاربری های ساخته شده، باغات، پوشش گیاهی، و اراضی فاقد پوشش گیاهی می باشد از طبقه بندی نظارت شده روش بیشترین مشابهت استفاده شده است. نتایج حاصل از مقایسه کاربری اراضی سال 1365 تا 1401 در محدوده مطالعاتی نشان می دهد که، در طی دوره مذکور کاربری مسکونی 94/175 کیلومترمربع افزایش داشته و کاربری باغات 28/74 کیلومتر روند کاهشی را نشان می دهد. همچنین در کاربری پوشش گیاهی شاهد کاهش 03/39 کیلومتری و در کاربری مناطق فاقد پوشش گیاهی 75/217 کیلومتر کاهش را شاهد هستیم. نتایج حاصل از بررسی دمای سطح زمین، نشان دهنده گسترش دمای سطح زمین در دوره مطالعاتی در شهر اصفهان می باشد. بر این اساس در دوره موردمطالعه، در نواحی شرق و جنوب شرق دمای سطح زمین در حال گسترش بودند. بررسی خطوط هم دما بیانگر این است که دمای سطح زمین در اطراف شهر ازنظر دمایی و وسعت افزایش قابل توجهی پیدا کردندThe Role of Land Use Changes in Shaping Surface Temperature in Cities: A Case Study of Isfahan"
The expansion and development of cities and the increase of urbanization are some of the current characteristics of human societies, especially in developing countries. Density and population growth in cities have led to the expansion and development of urban areas and changes in urban land use. In this research, a remote sensing technique was used to identify the patterns and examine the spatial changes in the surface temperature in different areas of Isfahan City. Using thermal equations and a similarity centre algorithm, the temperature of the earth's surface has been calculated for the periods of 1365 to 1401. The supervised classification of the most similar method was used to evaluate the changes in the land use of the studied area, which includes built uses, gardens, vegetation, and lands without vegetation. The results of the comparison of land use between 1365 and 1401 within the scope of studies show that during the mentioned period residential use increased by 175.94 square kilometers and garden use by 74.28 km shows a decreasing trend. Also, we see a decrease of 39.03 km in the use of vegetation and a decrease of 217.75 km in the use of areas without vegetation. The results of the earth surface temperature survey show the expansion of the earth surface temperature during the study period in Isfahan city. Based on this, in the studied period, the earth's surface temperature increased in the east and southeast regions. Examining the isothermal lines shows that the temperature of the earth's surface around the city increased significantly in terms of temperature and extent
Extended
Introduction
Howard first coined the term thermal island about a century ago, in 1833. Subsequently, numerous studies were conducted in major cities and industries around the world to find that urbanization caused significant changes. Consideration has been given to meteorological parameters and ground surface features, and consequently, many changes have been made in the local climate. Studies show that the role of thermoelectric sensing is crucial for studying the effects of thermal islands. Thermal remote sensing data have provided the opportunity to dynamically monitor and evaluate urban heat islands. Thermal remote sensing data is a unique source for defining the surface thermal island associated with the urban canopy thermal island. Synoptic meteorological station data have high temporal resolution and long-term overlap. Thermal remote sensing can provide an overview of each city and is particularly important for accurate city-level climate monitoring. Isfahan is at 51 degrees 39 minutes 40 seconds east longitude and 32 degrees 38 minutes 30 seconds north latitude. It is situated in a sedimentary plain that extends to relatively wide plains. Isfahan city covers an area of 106,786 square kilometers. Isfahan Province is one of the central provinces of Iran, with Isfahan city as its capital. The province ranks sixth in terms of area and third in population among all provinces in Iran and holds the first position in terms of urbanization in the country.
Methodology
This study used 7 images of Landsat OLI and EMT sensors and Landsat TM multilingual image. These images cover the period 1986 to 2022 (36 years period); due to the intensity of heat in the summer months, these images are for the summer months and then to reduce and eliminate image errors, a series of preprocessing and geometric and radiometric corrections were applied to the images. The supervised method is then used to classify the information. In this method, training samples were used to classify the pixels. Similarity centers algorithm was used to classify the monitoring. This method analyzes the value of bivariate and each unknown pixel based on the variance and covariance of that spectral reaction class. It assumes that the data distribution for each class is based on the normal distribution around the mean pixel of that class. Finally, the kappa method was used for model validation and classification. Analysis of land use changes in Isfahan County from 1986 to 2022 revealed that in 1986, the majority of land use categories were areas without vegetation cover, covering an area of 338.53 square kilometers (61.51%). The least land use category included water bodies and vegetation cover, with areas of 0.72 square kilometers (0.13%) and 40.90 square kilometers (0.89%), respectively. The built-up land use category was scattered in the northern, eastern, and central parts, covering an area of 73.88 square kilometers (24.02%). Orchards accounted for 132.18 square kilometers, representing 24.02% of the total area. The areas without vegetation cover were concentrated in the southern and southwestern regions, specifically in zones 5, 6, 9, and 13, in the eastern part of zone 15, and in the northern part of zone 12.
Results and discussion
The study's findings on land use changes in the area from 1986 to 2022 indicate that the built-up area increased from 8.73 square kilometers to 82.249 square kilometers. The vegetation covers also expanded from 9.40 square kilometers to 20.80 square kilometers. However, the area of orchards decreased from 132.01 square kilometers to 90.57 square kilometers. The areas without vegetation cover also decreased from 338.05 square kilometers to 78.120 square kilometers. Finally, the water bodies decreased from 0.72 square kilometers to 0 square kilometers in terms of land use. The examination of the relationship between isotherms (temperature lines) and land use in 1986 revealed that the highest temperature lines were associated with barren lands. Due to a lack of moisture, these lands become extremely hot during the day, leading to temperatures reaching up to 45 degrees Celsius (common in the plains and deserts of this county). Additionally, vegetation cover in the northeastern and northwestern directions acts as a natural modifier and cooler for the city. In this land use category, temperatures reach a minimum of around 30 degrees Celsius. For residential areas, which have experienced the most expansion in urban areas, the average temperature reaches around 40 degrees Celsius. This land use category acts as an intermediate zone among other land uses.
Conclusion
Investigations show that most articles have focused on land use changes or thermal islands but have not examined the role of land use and its changes on thermal island formation over 36 years. This study used the most modern and scientific remote sensing algorithms, first using Landsat satellite imagery to investigate the relationship between land use changes and surface temperature. Land use and temperature relationships indicate that residential areas have been replaced in urban areas due to population growth, buildings, cement, and asphalt organizations. These surfaces will absorb the sun rather than reflect it, raising the temperature in urban areas and dominating a particular climate. The results also showed that the Zayandeh Rud River and vegetation in the river water area were moderated.
Funding
There is no funding support.
Authors’ Contribution
All of the authors approved the content of the manuscript and agreed on all aspects of the work.
Conflict of Interest
Authors declared no conflict of interest.
Acknowledgments
We are grateful to all the scientific consultants of this paper.
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