Title: Simulation of land use change, rainfall and temperature in Mashhad metropolitan area during 1984-2030 period, using neural network model

Abstract

The aim of this study is to simulate land use changes, climate changes (temperature and rainfall) and population changes in Mashhad metropolitan area with an area of 181418.8 hectares in northeastern Iran, between 1984 and 2030. To achieve this goal, first by using Landsat 5, 7 and 8 satellite images in TeerSet and ArcGIS software. Land use changes were classified using the maximum likelihood estimation technique in five groups in 1984, 2000 and 2020. Then, the prediction of land use change for the periods of 2020-2030 was simulated using neural network and Markov chain. The results of land use change between 1984 and 2020 showed that barren lands increased by 15,993.7 (73.92%) hectares and built-up lands by 12,823.79 (59.27%) hectares, respectively. Green space lands have decreased by 15,811.71 (-73.08%) hectares. In the same period, the average temperature has increased by 2.6 degrees Celsius and the annual rainfall has decreased by 24 mm. The population of this metropolitan area has increased from 1,632,213 people to 3,345,409 people (growth of 2.04%) from 1986 to 2016, both urban (three cities of Mashhad, Targahba and Shandiz) and rural settlements (177 villages). The prediction of land use change for the periods of 2020-2030 using Marco chain model and neural network showed that the built-up land will increase by 13153.3 hectares (38.17%) and vacant land by 7503.91 hectares (11.34%). In the same period, green space will decrease by 12399.5 hectares (-26.21%) and mountain lands by 8389.13 hectares (-25.64%). Time-spatial distribution of land use from mountainous to built-up mainly in the southern slopes of the city and vegetation to the built-up mostly occurred in the north, northeast and northwest. The relationship between temperature and vegetation is negative (R=-0.11). But the relationship between temperature and built-up is positive (R=0.27). In general, the increase in the degree of drought and the decrease in rainfall have led to the barrenness of agricultural lands, providing the ground for the conversion of barren lands into built-up ones, especially as a result of population growth. The mutual influence of the above three factors is a serious threat to sustainable development in cities in arid and semi-arid regions. And it requires the development of environmental protection planning in line with the goals of sustainable development.