ارزیابی تأثیرات کاهش جزایر حرارتی شهری زیرساخت های سبز بر افزایش بهره وری کارهای سبک و سنگین: مطالعه موردی: کلانشهر تبریز (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
جزایر حرارتی شهری آثار زیانباری بر محیط زیست، سلامت و رفاه انسانی و بهره وری کارهای سبک و سنگین دارد. کاهش بهره وری و ظرفیت نیروی کار نیز آثار منفی اقتصادی زیادی به دنبال دارد. در این بین، زیرساخت های سبز شهری بر کاهش جزایر حرارتی شهری و به تبع آن بر افزایش کیفیت زندگی شهروندان، افزایش میزان سلامت، آسایش حرارتی شهروندان و افزایش میزان بهره وری کار تأثیر فزآینده ای دارد؛ از این رو محققان در پژوهش حاضر به نقش کاهشی جزایر حرارتی شهری زیرساخت های سبز کلانشهر تبریز در افزایش بهره وری کارهای سبک و سنگین پرداخته اند. در این پژوهش از داده های مرتبط با تصاویر ماهواره ای لندست (مربوط به سه دوره زمانی 1363، 1381 و 1401)، کاربری اراضی/ پوشش اراضی، داده های هواشناسی و جدول بیوفیزیکال استفاده شده است. همچنین در این پژوهش داده ها با استفاده از GIS و مدل سرمایش شهری نرم افزار InVEST تجزیه و تحلیل شده است. نتایج نشان داد که کلانشهر تبریز در سال 1363 در کلاس های 0، 25، 50 و 75 درصد به ترتیب 15/14، 53/3، 25/58 و 06/24 درصد، در سال 1381 در کلاس های 0، 25 و 50 درصد به ترتیب 89/1، 61/66 و 49/31 درصد و در سال 1401 در کلاس های 25، 50 و 75 درصد به ترتیب 24/0، 29/51 و 46/48 درصد از بهره وری خود را در کارهای سنگین از دست داده است. همچنین، کلانشهر تبریز در سال 1363 در بهره وری از دست رفته برای کارهای سبک در کلاس های 0 و 75 درصد به ترتیب 10/76 و 89/23 درصد از بهره وری خود را در کارهای سبک از دست داده و در سال 1381 تنها کلاس صفر درصد داشته است. به عبارت دیگر، تبریز در این سال در کارهای سبک هیچ گونه بهره وری را از دست نداده است. کلانشهر تبریز در سال 1401 نیز در کلاس های 0، 25، 50 و 75 درصد به ترتیب 54/51، 72/20، 68/22 و 05/5 درصد از بهره وری خود را در کارهای سبک از دست داده است.Evaluating the Effects of Mitigating Urban Heat Islands of Green Infrastructure on Increasing the Productivity of Light and Heavy Work (Case Study: Tabriz Metropolitan)
Urban heat islands have significant adverse effects on the environment, human health and well-being, and productivity of both light and heavy industries. Reduced productivity and labor capacity can lead to numerous negative economic consequences worldwide. Meanwhile, urban green infrastructure increasingly plays a vital role in mitigating urban heat islands, thereby enhancing citizens' quality of life, improving health and thermal comfort, and boosting labor productivity. This research examined the role of urban green infrastructure in the metropolitan area of Tabriz in alleviating the effects of urban heat islands and increasing productivity in both light and heavy work sectors. Data from Landsat satellite images from 1984, 2002, and 2022, along with land use/land cover information, meteorological data, and biophysical tables, were utilized for this study. The analysis employed Geographic Information System (GIS) and the urban cooling model of InVEST software. The results indicated that in 1984, Lost productivity for heavy work in Tabriz was distributed as follows: 14.15% in the 0% class, 3.53% in the 25% class, 58.25% in the 50% class, and 24.06% in the 75% class. By 2002, the figures shifted to 1.89% in the 0% class, 66.61% in the 25% class, and 31.49% in the 50% class. In 2022, lost productivity in heavy work productivity was reported as 0.24% in the 25% class, 51.29% in the 50% class, and 48.46% in the 75% class. Furthermore, in 1984, Tabriz experienced lost productivity for light work of 76.10% in the 0% class and 23.89% in the 75% class. By 2002, no districts in Tabriz reported lost productivity in light work. However, in 2022, lost productivity was recorded at 51.54%, 20.72%, 22.68%, and 5.05% for the 0%, 25%, 50%, and 75% classes, respectively. Keywords: Urban Heat Islands, Green Infrastructure, Productivity of Light and Heavy Work, Tabriz Metropolitan. Introduction Urban heat stress increasingly contributes to reduced productivity in both light and heavy industries, leading to significant economic losses. In contrast, urban green infrastructure plays a crucial role in enhancing citizens' quality of life, well-being, health, and thermal comfort, while also boosting productivity across various sectors. Tabriz, one of Iran's megacities, has undergone rapid urbanization and growth in recent decades. The challenges posed by urban heat islands, air pollution, and elevated temperatures threaten the city's viability. Consequently, the issue of urban heat island effects has become a pressing concern for this metropolitan area. This research explored the mitigating role of urban green infrastructure in Tabriz and its impact on enhancing productivity in light and heavy work sectors. Materials & Methods This research employed a descriptive-analytical methodology with a developmental-applicative focus. Data were collected through a combination of library resources, documentary evidence, electronic sources, surveys, and field observations. The study utilized the urban cooling model from the InVEST 3.12.0 software package, which calculated the mitigation of urban heat islands by considering factors, such as shading, evapotranspiration, albedo, and proximity to cooling islands like parks. In this model, vegetation cover served as a key parameter for estimating heat island mitigation. Ultimately, the model assessed the service value of heat island mitigation using two evaluation methods: energy consumption (potential energy reduction) and labor productivity (light and heavy work). The ecosystem service value of mitigating heat islands in the green infrastructure of Tabriz was calculated based on lost productivity in light and heavy work sectors. The primary inputs for the model included a land use/land cover raster map, a reference evapotranspiration (ET0) raster map, a biophysical table containing details about each land use/land cover class, a vector map of city buildings, and an energy consumption rate table categorized by building type and air temperature. Data from Landsat satellite images for the years 1984, 2002, and 2022, along with land use/land cover information, meteorological data, a biophysical table, and a detailed plan from the 2016 Tabriz municipality, were utilized. The analysis was conducted using GIS and the urban cooling model of InVEST. Landsat 5 satellite images were used for 1984 and 2002, while those of Landsat 8 were used for 2022. The land use/land cover map of the metropolitan area of Tabriz was prepared using ENVI 5.8 software and the Maximum Likelihood Classification (MLC) technique, resulting in a map categorized into 9 classes: high residential density, medium residential density, low residential density, open space, barren land, agricultural land, garden land, and pasture with a pixel resolution of 30 m. To prepare the reference evapotranspiration (ET0) map, the standard ASCE Penman-Monteith method—provided by the American Society of Civil Engineers—was employed. The biophysical table included essential information about each land use/land cover class, such as: Shadow Effect: Ranging from 0 to 1, this value relates to tree cover, specifically for trees exceeding 2 meters in height. Kc (Evaporation and Transpiration Coefficient): This coefficient reflects the relative evaporation and transpiration of each plant and soil type compared to the reference value, with values also ranging from 0 to 1. These values were sourced from the InVEST software manual for various land uses in this research. Albedo: This value, which ranges from 0 to 1, indicates the proportion of sunlight that each land use/land cover class reflects directly. Data regarding the impact of large green spaces on non-agricultural vegetation in artificial lands were also collected, with this effect quantified between 0 and 1. In terms of urban heat island intensity for the metropolitan area of Tabriz, the recorded temperature differences during the summer season were as follows: 3.2°C in 1984, 4.2°C in 2002, and 5.2°C in 2022. The reference temperatures for the village in those years were 28.1°C, 27.2°C, and 29.2°C, respectively. The maximum distance for air temperature mixing in Tabriz was set at 500 m, while the maximum distance to locate a large-scale green space (2 hectares or more) was established at 450 m. Research Findings The results revealed that in 1984, the metropolitan area of Tabriz had the productivity levels of 14.15%, 3.53%, 58.25%, and 24.06% across the 0%, 25%, 50%, and 75% classes, respectively. In 2002, these levels changed to 1.89% for the 0% class, 66.61% for the 25% class, and 31.49% for the 50% class. By 2022, productivity in the 25%, 50%, and 75% classes was recorded at 0.24%, 51.29%, and 48.46%, respectively. Regarding lost productivity in light work, Tabriz experienced losses of 76.10% in the 0% class and 23.89% in the 75% class in 1984. However, in 2002, all districts of Tabriz reported a 0% loss in productivity for light work as their Wet Bulb Globe Temperature (WBGT) was below 31.5°C. In 2022, the losses in productivity for light work were 51.54%, 20.72%, 22.68%, and 5.05% in the 0%, 25%, 50%, and 75% classes, respectively. Discussion of Results & Conclusion The results indicated that agricultural land and green spaces played a crucial role in reducing Wet Bulb Globe Temperature (WBGT), mitigating urban heat islands and consequently minimizing productivity losses in both light and heavy labor across the metropolitan area of Tabriz. In 1984, regions of Tabriz with agricultural use, green spaces, and low residential density exhibited the lowest WBGT levels, resulting in minimal productivity losses for both light and heavy work. Conversely, areas characterized by barren land and higher residential density experienced elevated WBGT levels, leading to greater productivity losses. By 2002, regions with increased agricultural land and green spaces continued to show the lowest WBGT levels, while areas with barren land and higher residential density recorded the highest WBGT and subsequent productivity losses. In 2022, the pattern remained consistent: areas rich in agricultural land, green spaces, open areas, and low residential density exhibited the lowest WBGT and the most effective mitigation of urban heat islands, resulting in the least productivity loss for light and heavy work. In contrast, regions dominated by barren land and higher residential density faced the highest WBGT levels, the least effective urban heat island mitigation, and the greatest productivity losses.
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