Investigation and Evaluation of the Relationship between Land-use and Temperature Variations within the Urban Environment using Nighttime Thermal Data from the Aster Sensor: A case study of Meshginshahr city

ABSTRACT
Population growth and the need for more urban space for residences lead to more city land being put under construction, and the city is facing land use changes. By affecting the urban climate, land use change causes changes in the energy balance, increases land surface temperature, and air temperatures in urban areas. Therefore, the impact of different land uses on land surface temperature is an important issue that a detailed study of this can lead to better management to reduce the adverse effects of heat islands in cities. In this study, using remote sensing as a new method, the relationship between land use change and nighttime land surface temperature in Meshkin Shahr city was studied using thermal data from the ASTER sensor and the Sentinel 3 satellite to identify hot spots that are precursors to the formation of heat islands in the urban environment. Regarding the research problem, the land surface temperature was first estimated using a split window algorithm for nighttime images from the ASTER sensor. The estimated temperature was then validated using the Sentinel-3 thermal product. Then, using the Landsat 9 image and the SVM algorithm, land use was extracted. Next, the relationship between land surface temperature and topographic factors (slope and aspect) and land use was investigated and analyzed. Finally, factors such as the asymmetric combination of phenomena with different characteristics and heat capacity, irregular distribution of vegetation, and barren lands as a result of urban expansion were inferred in the identification and distribution of hot spots using the Getis-Ord algorithm in the study area.
Extended Abstract
Introduction
Rapid urban expansion, due to extensive changes in land use and cover, has had negative impacts on global environmental quality, including air quality, temperature increase, and landscape changes, as well as agricultural land conversion leading to biodiversity loss. Accordingly, cities often experience specific climatic conditions, which are called urban climates. Urban climates are characterized by differences in the city's climatic variables (air temperature, humidity, wind speed and direction, precipitation) with the surrounding low-density areas. City climate can be improved by planning the city's structure, through strategies such as locating parks and water areas (such as ponds) and constructing buildings in the direction of the winds, which results in air pollution being blown away from the city by the wind. In this regard, the land surface temperature is an important parameter that controls the physical, chemical, and biological processes of the Earth and is an important factor for studying urban climate, which affects the balance of radiation, heat flux, evaporation, and transpiration, and other key factors in urban environments, which has recently been considered an important factor in many studies. How different land uses affect the land surface temperature is an important issue, and careful study of it will lead to better management to reduce the adverse effects of heat islands in cities.
The topic addressed in this research is the investigation and evaluation of the role of urban land use changes on the formation of the land surface temperature pattern in Meshginshahr city. Our goal is to investigate the impact of land-use changes in Meshginshahr city on the land surface temperature of different areas of this city at night, considering its topography. In other words, can land use changes cause changes in the land surface temperature at night in Meshginshahr city?
 
Methodology
The study area is located between latitudes 38 degrees and 22 minutes to 38 degrees and 25 minutes north and longitudes 47 degrees and 38 minutes to 47 degrees and 42 minutes east. The selected study area covers an area of about 9.83 square kilometers. In this study, in order to estimation of the land surface temperature using aster images and also to extract land use from envi software as the main image processing software, snap software for primary processing, geometric correction and preparation of sentinel 3 images for use in complementary software, we use terrset software for land surface temperature validation was retrieved and arcgis software for the processing of hot spot analysis and their relationship with the extracted uses, as well as the preparation of the output map.
 
Results and discussion
The high spatial resolution of remote sensing sensors for studying heterogeneous areas with diverse phenomena is an important and influential feature in the findings of studies, given that we are dealing with different dimensions and sizes of phenomena. Thus, in the present study, aware that urban areas are considered heterogeneous areas, to extract the ground surface temperature alongside the aster sensor which has a resolution of 90 meters for the thermal band from the sentinel 3 thermal sensor, which has a one-kilometer resolution for the same band, was used to reveal difference in detail in the findings further. Emphasizing this point, the relationship between land-use and land surface temperature was studied for the urban area in question. The research findings indicated the negative effects of land-use change as a result of the increase in built-up areas and the lack of planning by urban managers in the final map so that areas of the city that are close to areas with vegetation are marked as cold spots however, some areas appear as hot spots, which can also be affected by construction, expansion, and renovation of the city. Nevertheless, in this same image, we see that barren areas that have lost their natural cover or have little natural cover appear as hot spots knowing that surfaces with natural cover, such as plants, water areas, and the like, which contain moisture, can be effective in reducing air temperatures. Thus preventing excessive decreases in land surface temperatures during the cold seasons of the year, it can be seen that the outskirts of the city, especially the south, southeast, and west, which do not have the necessary coverage, have been identified as cold spots at night and hot spots tend to be more towards the center and eastern periphery. Although meshginshahr is not a large city, if proper management is not carried out to preserve its natural cover along with changing land use during urban development, as a tourist city that has the potential to develop and increase its population, in the not-so-distant future it will face serious problems of heat islands, excessive energy consumption, and consequently a negative impact on the health of citizens and the environment.
 
Conclusion
The analysis of land-use temperature between both sensors, in addition to the existence of a common point, showed a difference in land use temperature for the date 2023/12/18, which was justifiable given the spatial resolution of the sensors. Also, the relationship between temperature and land use showed that the temperature of land uses is more influenced by the topography of the region and the thermal characteristics of the phenomena. The results of the relationship between land surface temperature and topographic factors (slope and aspect) showed a positive relationship between land surface temperature and slope in the warm season and an inverse relationship in the cold season. In addition, for both sensors, the highest temperatures were in the southern, southeastern, and western geographical directions, which showed a significant relationship between temperature and aspect. Finally, by implementing the getis-ord algorithm, factors such as the asymmetric combination of phenomena with different characteristics and heat capacity, irregular distribution of vegetation cover, and wasteland as a result of urban expansion were inferred as the main factors in identifying hot spots.
 
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.