عنوان مقاله [English]
The land surface temperature is the highest layer of the earth's surface and depends on the level of surface emission, vegetation and the types of ground cover. Earth's surface temperature provides important information about the physical characteristics of the Earth's surface from local and global scales, and plays an important role in many applications. From Earth's surface temperature to study water resources management, agriculture, resource management, drought, environmental geochemical processing, meteorological research, global changes in land surface temperature, weather forecasting, hydrology, ecology, plant status survey, urban climate, studies Environmental and geophysical variables such as evaporation-transpiration and soil moisture are used. In general, temperature measurements at ground level are performed by meteorological stations, including synoptic and climatological. It should be noted that meteorological stations are only able to measure the temperature at specific points that have already been installed there. What is considered to be a major flaw in ground temperature monitoring is the lack of sufficient meteorological stations to know the temperature values in stations without stations, which have been partially remedied today by remote sensing technology. Earth's surface temperature is one of the most important components in global studies, which is used as one of the important factors in controlling the biological, chemical and physical processes of the earth.
Materials & Methods
Moghan plain is located in the northwest of Iran and is subject to Ardabil province and is located in the northern part of the province. ParsAbad Moghan city is a relatively large plain with an area of 143494 hectares, which occupies about 14% of Ardabil area and is the northernmost city of the province. The data used in this study included the Landsat 8 satellite image, which used its OLI sensor to extract land use maps and its TIRS gauge used to extract the Earth's surface temperature for 2018, as well as the ETM + Landsat imager to prepare land use maps. Using visible and infrared bands and surface temperature using thermal bands for 2002. The city's meteorological data were also used to check the temperature recorded by the stations. The ENVI 5.3 software was used for atmospheric and radiometric corrections, and the ARC GIS 10.5 software was used to extract the relevant maps. In order to classify land use, object-oriented classification method was used in eCognition Developer64 software. In object-oriented classification, spectral information is integrated with spatial information, and pixels are segmented based on the shape, texture, and gray tone of the image at a specific scale, and image classification is based on these components.
Results and discussion
The largest area in 2002 belongs to the rangeland class with an area of 58,138 hectares. The second area belongs to the dryland agricultural class, which has the largest area with 52369 hectares. The smallest area belongs to the use of water with 543 hectares. For 2018, rainfed agriculture had the highest area with 41906 and then pasture with 30943 had the highest area. Looking at the uses of 2018, the results show a significant difference that the use of soil has increased from 11143 in 2002 to 30943 in 2018, as well as the use of irrigated agriculture and residential areas and forests. However, the use of irrigated areas has decreased significantly from 543 hectares to 262 hectares, and the use of rainfed and rangeland agriculture has also decreased compared to 2002. The water temperature during 2018 was almost constant and did not differ significantly, and the lowest temperature in both years is 31 degrees. Due to the fact that water has a high heat capacity, water has a lower surface temperature to the soil has the highest temperature in both years with 40.80 for 2002 and 42.92 for 2018. Aquaculture in 2003 was 33.12. C, which in 2018 increased to 34.41. C. The rangeland use has had a high temperature in both years of study and has increased from 38.22 in 2002 to 39.26 in 2018.
In this research, in the first step, in order to classify and then examine the changes that occurred in a certain period of time in the city of ParsAbad, action was taken. For this purpose, in the first stage of this research, in order to classify and record changes in a 16-year period, object-oriented images were classified in eCognition software and in ArcGIS10.5 software, extraction maps were extracted. Was. The classification accuracy in 2000 has a total accuracy of 0.90 and a coefficient of 0.87. While the classification in 2018 with an overall accuracy of 92% and a Cape coefficient of 0.90 has provided a relatively higher accuracy. After classification, an attempt was made to examine the changes that occurred in the region over a 16-year period, and a map of land use changes was drawn up for the area under study. Land surface temperature is one of the main parameters in the study of cities. Because it is almost the same as the air temperature in the lower layers of the city, which is the energy balance of the surface and determines the climate between the buildings and affects the life and comfort of the urban residents. Soil use has the highest temperature in both years with 40.80 for 2002 and 42.92 for 2018. Also noteworthy about residential areas is that residential use has increased from 34/51 in 2002 to 40/09 in 2018, which indicates that in 2018, with the expansion of the city compared to 16 years ago, the heat concentration will also increase. Increased. This use is due to the presence of man-made and heat-absorbing factors such as asphalt, concrete, the existence of various machinery and factories, as well as the creation of tall buildings that prevent heat from escaping around and prevent wind from moving into the city.