Abstract

The integration of remote sensing techniques and Geographic Information System (GIS) has a wide use to quantify the spatiotemporal distribution of vegetation cover, land degradation, and rising temperature. Over the last decade, a remarkable change was noticed in climate, land degradation, and vegetation cover in Duhok.

Firstly, the Modified Soil Adjusted Vegetation Index (MSAVI2) was extracted from Landsat satellite images over the 20 years (2000 to 2019). For analyzing the vegetation changes, the terrain data (elevation, slope, and aspect) and climate data (temperature and rainfall) are used.

The result shows that from 2000–2019, the average mean vegetation was 0.361 and the trend increased in 77.9% of the study area. The northern and northeastern parts of the study area revealed a significant increase in vegetation, while in the low land areas it was decreased. The amount of rainfall and temperature degree affect the spatiotemporal distribution of vegetation cover.

The vegetation showed a positive relationship with rainfall and temperature. At elevation less than 2000 m, with increasing elevation the vegetation is increasing, but when the elevation reaches 2000 m, the vegetation is decreasing and negatively related to elevation. The vegetation has a positive relation with slopes less than 45°, and at slopes higher than 45°, the vegetation is decreased. The impact of aspect on the vegetation figured out that the largest vegetation is detected in the shady slope due to relatively less evapotranspiration.

Secondly, a curious change was realized in temperature in the Duhok district in the last two decades. The temperature rise has become a serious environmental concern affected by both anthropogenic and natural factors. Worldwide, rising land surface temperatures have emerged the most pressing issues facing the twenty-first century.

Hence, this study examined the spatiotemporal land surface temperature (LST) distribution and Modified Soil Adjusted Vegetation Index (MSAVI2) and the correlation between them in the Duhok district in three different years 2001, 2011, and 2021 using Landsat satellite images. Air temperature data from seven weather stations were used to validate the LST results.

The study’s findings revealed that the Duhok district’s LST has risen during the study period. In general, the average LST has been increasing at a rate of 0.15 °C per year. Other findings showed that the vegetation cover of the Duhok district has changed dynamically.

In all three years of study, the regression analysis results indicated that there was a negative correlation between LST and vegetation. These methods of evaluation will be useful in guiding future urban management work and local government strategies.

Lastly, over the last decade, a marked change was observed in land degradation in the Duhok district. Land degradation is a complex process and significant environmental problem affected by both natural and anthropogenic driving factors. Globally, the prevention of land degradation has become one of the most significant challenges of the twenty-first century.

GIS, Multispectral remotely sensed satellite image, and Analytic Hierarchy Process are efficient tools for modelling and assessing the risks of land degradation. To analyze land degradation, in this study, various physical and human-induced factors were used in a GIS environment; slope, elevation, drainage, rainfall, geology, vegetation coverage, and land use/ land cover.

The data were analyzed, and weights assigned to each factor using the analytic hierarchy process and mapped using GIS techniques, resulting in a land degradation map. Field observations were carried out to better understand the degree of various factors that contribute to land degradation by using recent technologies and a global positioning system in the study area.

The results showed that 11.74% and 28.69% of the studied area (Duhok district) were affected by high and moderate levels of land degradation, respectively, while 34.77% and 24.79% of the study area experienced slight and no degradation, respectively. Slope gradient, rainfall, and distribution of vegetation were identified as the primary causes of land degradation in the area.