A B S T R A C T
Solar energy has been considered as a reliable solution for generating electricity necessary for human life. The inherent advantages of solar energy, including its universal accessibility without initial financial outlay, extended operational lifespan, and inherent usability, render grid infrastructure and associated costly components (e.g., transformers) redundant. Furthermore, its facile installation, rapid transportability, and suitability for deployment in proximity to end-users, as well as its application in mobile systems and provision of power to remote off-grid locations, collectively underscore its inevitable adoption. To conduct this research, images from the year 2024 of the Landsat 8 satellite, OLI and TIRS sensors, and the SEBAL algorithm were used. ENVI software was employed for geometric, atmospheric, and radiometric corrections of satellite images and for executing calculations related to the SEBAL model. Furthermore, ArcGIS software was used to create a database, spatial analyses, cartographic operations, and finally the implementation of the model. The results indicate that the average maximum incoming shortwave radiation was 846 watts/m2 in August and the lowest was 313 watts/m2 in February. It is concluded that solar radiation consistently reaching up to 1000 W/m². Therefore, solar radiation in the villages of Chalous County has the necessary potential for implementing solar photovoltaic projects.

Extended Abstract
Introduction
Despite the paramount importance of solar radiation, its measurement is limited, and this deficiency is not only evident in developing countries but also in developed countries. The measurement of temporal and spatial variations in solar radiation is carried out by a network of meteorological stations equipped with pyranometers. The equipment for measuring this meteorological parameter is expensive and requires special techniques. In addition, the relevant devices, due to their sensitivity, require a lot of care and must be calibrated regularly. Most meteorological stations in Iran and the world lack this equipment, and there are many statistical gaps in the statistics and information available for such stations. Therefore, given the small number of stations with radiometric instruments in the country and the existence of statistical gaps in radiometric stations, the data available for studies of spatial and temporal changes in radiation reaching the Earth are limited and have low accuracy due to the dispersion of measurement networks, and it is necessary to conduct and continue studies on this issue. The use of satellite data provides studies on a large scale and reduces costs and prevents waste of time. It also reduces the adverse effects of projects on the environment and paves the way for achieving sustainable environmental development and dynamic agriculture. Given the importance of solar radiation as a clean, accessible and free from any harmful environmental pollution, identifying its emission areas is essential and necessary for introduction to the relevant authorities. In this research, the feasibility of using solar energy in the Chalous County region using the SEBAL algorithm and remote sensing technology. Given the importance of using solar radiation energy, numerous studies have been conducted in the realm of scientific literature throughout the world and in Iran. According to scientific estimates, about 6000 million years have passed since the birth of this ball of luminescence, and every second, 2.4 million tons of the mass of the Sun is converted into energy. Therefore, considering the weight of the Sun, which is about 333 thousand times the weight of the Earth, this luminous sphere can be considered as a huge source of energy for the next 5 billion years. Energy is one of the essential factors in economic and social development and improving the quality of life. Due to the high potential of solar energy, this energy can be used in solar heating systems and solar batteries. Knowledge of the radiation reaching the Earth's surface is essential for solar radiation experts, architects, building design engineers for energy efficiency and other applications of solar radiation. Knowledge of the solar radiation reaching the Earth and its geographical distribution is important for measuring spatial changes in hydrological and meteorological processes, biology and other energy applications. Designing solar energy conversion systems and estimating their efficiency at a specific location requires reliable solar data for short time intervals over long periods.

Methodology
Landsat satellite images were used in a period for the months of 2023 to investigate and assess the feasibility of utilizing solar radiation energy. ENVI software was employed to conduct geometric, atmospheric, and radiometric corrections of satellite images, as well as to perform calculations related to the SEBAL model. In addition, ArcGIS software was used to create a database, conduct spatial analyses, perform cartographic operations, and finally implement the model. Subsequently, calculations related to the SEBAL model were performed in the ENVI and ArcGIS software environments, and the amount of net radiation was calculated and analyzed in the study area. It is noticeable that the images available for the months of the year for the study area were totally cloudy, and given that in the SEBAL algorithm, net radiation values are obtained by measuring the incident solar radiation from cloud-free images. It was not possible to use the images of the above-mentioned months. In this study, atmospheric effects were removed as much as possible using the Landsat satellite atmospheric correction function in ENVI software, and finally, radiometric corrections were applied to the images to eliminate any gaps and strips. In the SEBAL algorithm, satellite image data in the visible, near-infrared, and thermal bands are used to estimate net radiant energy, soil heat flux, sensible heat flux, and latent heat flux of evaporation for each pixel in an image. In this method, instantaneous net radiation values are obtained by measuring the incident solar radiation from cloud-free images and using surface albedo, surface emissivity, and surface temperature. Chalus County has been selected as a case study. This county is located in the southern Caspian Sea region with an area of about 1600 square kilometers. In terms of the settlement system in Chalus County, the two northern and central parts are the places where the activity and residential systems are established. So that the northern area is connected to the central part by a road axis. The border separating these areas is dense forest areas and the Alborz mountain range, which has caused a large part of the county to be allocated to forest, pasture and barren areas. The northern part contains about 78 percent of the total population of the province. Special environmental conditions have caused the emergence of special land use in the region. The use of energy as an alternative to fossil fuels, considering its environmental and economic characteristics, is one of the concerns of energy policymakers in the current century. What has intensified the trend of attention to new energies in different countries is the growth of energy consumption and excessive use of fossil energy resources, the problems in the energy supply sector, and the warming of air temperatures caused by greenhouse gases.

Results and Discussion
In this study, Landsat satellite images were used in a period for the months of 2023 to investigate and assess the feasibility of using solar radiation energy. ENVI software was adopted to perform geometric, atmospheric, and radiometric corrections of satellite images, as well as to carry out calculations related to the SEBAL model, and ArcGIS software was used to create a database, conduct spatial analyses, perform cartographic operations, and finally to implement the model. Subsequently, calculations related to the SEBAL model were performed in the ENVI and ArcGIS software environments, and the amount of net radiation calculated and analyzed in the study area. It should be noted that the images available for the months of the year for the study area were completely cloudy, and given that in the SEBAL algorithm, net radiation values are obtained by measuring the incident solar radiation from cloud-free images, it was not possible to use the images of the above-mentioned months. In this study, atmospheric effects were removed as much as possible using the Landsat satellite atmospheric correction function in ENVI software, and finally, radiometric corrections were applied to the images to eliminate any gaps and strips. In the SEBAL algorithm, satellite image data in the visible, near-infrared, and thermal bands are used to estimate net radiant energy, soil heat flux, sensible heat flux, and latent heat flux of evaporation for each pixel in an image. In this method, instantaneous net radiation values are obtained by measuring the incident solar radiation from cloud-free images and using surface albedo, surface emissivity, and surface temperature. The purpose of solar power is to rely entirely on the sun's radiant energy, which is an inexhaustible and renewable resource. Solar panels are made up of photovoltaic cells that convert the sun's radiant energy into direct current (DC). These cells are usually made of materials such as silicon that have special electrical properties. When sunlight hits the solar cells, the photons of light cause an electrical current to flow through the cells, which is converted into DC. A system in which solar energy is converted into electrical energy without the use of moving or chemical mechanisms is called photovoltaic effect. The element used in this process is called solar cell. These cells were first used as electrical generators in spacecraft about 45 years ago and have been used on Earth for some time now. Solar cells are capable of converting solar radiation energy directly into electricity with an efficiency of 5 to 20 percent. Although photovoltaics are not yet economically viable, in recent years there has been a significant reduction in the costs of operating these systems, and it is expected that the price will continue to fall in the future with further research into the type of photovoltaic cells. These systems are also called solar power. Electricity is generated by using sunlight and solar cells, and by creating an electrical pressure difference in appropriately manufactured semiconductors.

Conclusion
Global solar radiation is considered one of the fundamental structures of any climatic range. Therefore, understanding the characteristics and predicting these fundamental structures have a great impact on energy-related planning. The use of satellite images and remote sensing models as a suitable and low-cost tool has been employed in recent years for estimating solar radiation. In the present study, images were utilized that obtained from the Landsat 8 satellite, OLI and TIRS sensors, and the SEBAL algorithm. The results show that the average maximum incoming shortwave radiation was 769 watts per square meter in September and the lowest value in May was 318 watts per square meter. The inconsistency in the amount of net radiation reaching the Earth in the study area is due to the difference in the angle of the sun's rays and the number of sunny hours in different months of the year. Finally, solar radiation in the region has the necessary potential for implementing solar photovoltaic projects. Photovoltaic cells that are sensitive and receive solar radiation ranging from the radiation threshold to 1000 watts per square meter. In conclusion, solar radiation in Chalous County and its villages has the necessary potential for implementing solar photovoltaic projects.
September shows a significant increase in the radiation power and net radiation compared to previous months. Also, the highest percentage of net radiation distribution in this month is in the range of 700-769 watts per square meter, and the lowest radiation in this month is in the range of 300-352 watts per square meter of net radiation. Chalus County has the highest net radiation distribution temperature in all parts of the county. The reason for this is that even in the lowest radiation power, the figure of 300-352 is very high compared to previous months. Also, the highest percentage of net radiation distribution in September is in the range of 590-641 watts per square meter with a value of 23.40 percent of the total net radiation. Also, the highest percentage of net radiation distribution in June was in the range of 288-296 watts per square meter, with a value of 28.33 percent of the total net radiation. Using satellite images and remote sensing models as a suitable and low-cost tool for estimating solar radiation has better performance than empirical methods. Therefore, it is suggested that researchers use satellite images and remote sensing methods to study solar radiation instead of temporal analyses of climate data and empirical methods. Investing in solar power generation can be one of the desirable and profitable investments that, in addition to economic benefits, also serves humans and the environment in various ways. Investing in solar power generation can be in the form of purchasing solar equipment and setting up off-grid power plants so that you can supply the electricity you need. Of course, this is not economically justified if you have access to grid electricity. In fact, investing in solar power generation is more common in the form of setting up an off-grid power plant or a home solar power plant. In a way, people who have the conditions to set up this power plant on the roof of their house or another place can set it up and sell their generated electricity to the grid through a contract with the electricity department. The return on investment in this method was about 4 years in the early years, but now, due to the increasing cost of equipment, it is slightly higher. Of course, it is possible that the return on investment will occur sooner, or that changes will be made to the terms of the guaranteed power purchase agreement, given the new policies that the SATBA organization is implementing.

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.