Abstract

The increase in population and expansion of constructions have caused many changes in ecosystems. Among them, can mention the increase in the earth's surface temperature, desertification, dust and decrease in rainfall, etc. In order to preserve the environment and prevent negative changes, accurate information on the amount and rate of changes should be prepared. Nowadays, remote sensing technology has been developed, and it can be used to analyze the changes and influential factors with proper accuracy and make an accurate plan based on them. The purpose of this article is to investigate the changes in land cover in Khuzestan province during 22 years and to evaluate the correlation of land cover changes with environmental factors such as land surface temperature and precipitation.

Material & Method: In this research, the trend of land cover changes has been determined by using the Modis sensor, and the correlation between rainfall and land surface temperature with land cover changes has been investigated. Using the MODIS riverb website, 22 years of images for Khuzestan Province were extracted. Subsequently, in the ArcGIS software, the area corresponding to each type of land cover was extracted, and finally, with the help of Excel software, the extent of changes in the areas of different land covers was determined. Furthermore, precipitation data were extracted using the Terra Climate model, which is based on data from synoptic stations around the world and models with a resolution of 2.5 minutes for all regions of the world. Finally, precipitation data for the years 2001 to 2022 were extracted through the Google Earth Engine, and for collecting temperature data, the 8-day product from the MODIS sensor was used.

Results and discussion: According to the results, during the investigation period, the temperature was almost constant, but the precipitation decreased. Also, the results show that during this period, about 8% of the total land cover has changed. According to the results obtained, from 2001 to 2022, 8.2 percent of the area’s coverage has changed. Among the examined covers, the highest increase in area corresponds to scattered shrub land and barren land, which have increased by 1260 and 1044 square kilometers, respectively, while the area of pastures has decreased by 2282 square kilometers. When considering the relative changes in different covers, permanent wetland areas have experienced the highest increase of 188 percent, while composite agricultural cover and natural lands have seen the most significant relative decrease of 95 percent. According to the land cover product (MCD12Q1), water cover has shown an increasing trend over these 22 years. Water areas have increased by approximately 16.93 percent during this period. Considering the decreasing trend in precipitation, water cover has a direct relationship with other environmental factors. The permanent wetland class consists of the Hoor al-Azim and Shadegan wetlands, located in the southern and eastern parts of the province, which have increased in area by about 188.8 percent over 22 years and have an inverse relationship with precipitation. The barren land class has also shown an increasing trend, indicating negative changes in the ecosystem of the southern region of the province.



Conclusion: One of the most important applications of remote sensing data is the study and examination of dynamic and changing phenomena over time. Dynamic phenomena include agricultural crop growth, water resource depletion, soil degradation, vegetation loss, land degradation, and desertification. Change detection is a process that allows for the observation and identification of temporal differences and variations in phenomena, features, and patterns on the Earth's surface. One of the most important findings of this research is the increase in the area of scattered shrubs and barren lands, with the area of scattered shrubs increasing by 5.33% and barren lands by 5.56%. This increase may be due to the degradation of pastures and their conversion into barren lands. On the other hand, the decrease in rainfall during the study period (Table 2) and consecutive droughts could also be another possible reason for these changes. Also, according to the results, the area of pastures has decreased by 20.46%, savanna by 58.05%, and mixed agriculture with natural lands by 95.33%. The reduction in pastures may be due to overgrazing, land-use change to agriculture, or urban development. The decrease in rainfall could also play a significant role. Possible reasons for the decline in mixed agriculture include changes in cropping patterns, water shortages, or the conversion of agricultural lands into residential areas. Another finding of the present study is the increase in the area of cities and human-made lands by 2.03%, indicating urban and industrial development in Khuzestan Province, which could lead to increased temperatures and reduced vegetation cover. This is consistent with the findings presented by Keikhosravi (2019) regarding the reduction of vegetation cover due to the development of residential areas and the creation of urban heat islands.

In general, the results of this study indicate that land cover changes in Khuzestan Province are influenced by various factors, including climate change, human activities, and water resource management. To better manage natural resources and mitigate the negative effects of these changes, comprehensive planning based on accurate and up-to-date data should be implemented, with attention given to the interactions between different factors.