بررسی تأثیر خدمت اکوسیستمی خنک‌کنندگی زیرساخت‌های سبز شهری بر کاهش بار گرمای محیطی و بهره‌وری انرژی در کلان‌شهر تبریز

ABSTRACT
This research evaluated the effects of green infrastructure cooling ecosystem service on mitigating urban heat islands in Tabriz metropolitan areas. In this way, the mitigation capacity of the heat islands of Tabriz in all three periods of 1984, 2002, and 2022 was evaluated in 5 classes, from the best case to the worst case, using the urban cooling model of the InVEST software. The results showed that Tabriz condition in 1984, i.e., 15.47% in the class of 0.69 to 0.83%; in 2002, 15.63% in the class of 0.66 to 0.90%; and in 2022, 13.93% in the class of 0.69 to 0.83%, was able to mitigate heat islands. In other words, the Tabriz metropolitan did not perform well in mitigating heat islands in all three periods and is in the worst condition. In all three time periods, the mitigation pattern of heat islands in Tabriz has been consistent with the pattern of agricultural land use and green space of all three types of cluster, block, and fragmented patterns. The pattern of mitigation of heat islands in Tabriz in 2022, unlike in 1984 and 2002, was more fragmented and less than cluster and block type, indicating that Tabriz's green infrastructure has gradually become fragmented and smaller. In 1984, 2002, and 2022, Tabriz Metropolitan had 226,640, 562,269, and 1,263,294 megawatt hours of energy savings due to the mitigation of heat islands due to urban green infrastructure
Extended Abstract
Introduction
During the past decades, with the rapid growth of urbanization, the subsequent increase in land use changes, and the transformation of natural surfaces into impervious and artificial urban surfaces, urban heat islands have become more intense. Urban heat islands harm the environment and the health and welfare of humans and other living beings in cities. Meanwhile, urban ecosystems such as urban green infrastructure such as vegetation, urban green spaces, urban parks, and urban water infrastructure such as rivers and urban water bodies play an increasing role in mitigating urban heat islands. Tabriz is one of the megacities of Iran that has experienced rapid urbanization and growth in recent decades. Urban heat islands, polluted air, and high temperatures threaten urban viability in Tabriz. Therefore, the problem of urban heat island tension has become a serious issue in this metropolitan. Therefore, in this research, the effects of cooling ecosystem services of green infrastructure on the mitigation of urban heat islands in Tabriz have been evaluated.
 
Methodology
The current research is descriptive-analytical in terms of method and has a developmental-applicative nature. The required information was collected using the library, documentary, electronic sources, surveys, and field observations. This research used the urban cooling model from the InVEST 3.12.0 software package. The urban cooling model calculates the mitigation of urban heat islands based on shading, evaporation transpiration, albedo, and the distance from cooling islands (such as parks). In this model, vegetation cover is used to estimate the mitigation of heat islands. Finally, the model estimates the service value of heat island mitigation using two evaluation methods: energy consumption (potential energy reduction) and labor productivity (light and heavy work). The main inputs of this model include a land use/land cover raster map, a reference evaporation and transpiration raster map (et0), a biophysical table containing information about each of the land use/land cover map classes, a vector map of city buildings and energy consumption rate table is based on the type of buildings and air temperature. In this research, data related to Landsat satellite images (related to three time periods as 1984, 2002, and 2022), land use/land cover, meteorological data, biophysical table, and a detailed plan map of the 2016 Tabriz municipality have been used. This research analyzes the data using GIS and the urban cooling model of InVEST software.
 
Results and discussion
The results showed that Tabriz in 1984 in class 0.097 to 0.18 percent, i.e. the worst condition is 54.65 percent, and then in class 0.19 to 0.34 percent, 17.98 percent, and in class 0.69 to 0.83 percent in the best condition, 15.47 percent, in 2002 in class 0.097 to 0.18 percent, that is, in the worst condition, 46.34 percent, after that class 0.19 to 0.31 percent with 18.80 percent and class 0.66 to 0.90 percent means the best condition with 15.63 percent and in 2022 in class 0.098 to 0.18 percent that is in the worst condition 34.90 percent and after that in class 0.36 to 0.50 percent that is, 33.38 percent, and in the class 0.69 to 0.83 percent in the best condition, 13.93 percent dedicated for the greatest mitigation of urban heat islands. In other words, Tabriz has not performed well in mitigating heat islands and is in the worst condition. In all three periods of 1984, 2002, and 2022, the urban heat island mitigation pattern in Tabriz was consistent with agricultural land use and green space (the main cold islands of Tabriz metropolitan) of all three types of cluster, block, and fragmented patterns. However, in 2022, it was more fragmented, less clustered, and blocky.
 
Conclusion
The results showed that in 1984, in the parts of Tabriz metropolitan where there was agricultural use, green spaces, and low residential density, respectively, the most significant mitigation of heat islands occurred, and in the parts where there were barren lands, high and medium residential density, the mitigation of heat islands is in the worst situation. In 2002, in the parts of Tabriz where there are agricultural lands and green spaces, we saw the greatest mitigation of heat islands. In the parts with barren lands and high and medium residential density, we saw a reduction of low heat islands. In 2022, respectively, in the areas where there were agricultural lands, green spaces, open spaces, and low residential density, the greatest rate of heat island mitigation, and in the areas where there were barren lands, high and medium residential density, the least mitigation of heat islands has occurred. Also, in 1984, 2002, and 2022, green infrastructure in Tabriz neutralized 82.81, 90 and 82.88% of urban heat islands, respectively. Overall, the results showed that the metropolitan of Tabriz did not perform well in mitigating heat islands in all three time periods of 1984, 2002, and 2022 and is in the worst condition. Considering that Iran is one of the developing countries and Tabriz, as one of the megacities of Iran, has undergone rapid urbanization in recent decades, the green infrastructures in Tabriz are more fragmented, and the fact that the metropolitan of Tabriz in all three periods, the amount of green space use was lower than other uses. Therefore, this metropolitan area performed poorly in mitigating urban heat islands in all three periods.
 
Funding
There is no funding support.
 
Authors’ Contribution
Authors contributed equally to the conceptualization and writing of the article. All of the authors approved thecontent of the manuscript and agreed on all aspects of the work declaration of competing interest none.
 
Conflict of Interest
Authors declared no conflict of interest.
 
Acknowledgments
We are grateful to all the scientific consultants of this paper.