High-resolution geomorphological structures in the Qaidam Basin analyzed with ENVI

Abstract

A study of the high-resolution geomorphological structures in the Qaidam Basin analyzed with ENVI (The Environment for Visualizing Images), was conducted to investigate the arid and sparsely inhabited Qaidam Basin with a fragile ecology and particular geomorphological structure. Given the limited number of meteorological stations, this study aims to analyze the spatial distribution of terrain and geomorphologic structure using high-resolution remote sensing data, and to extract Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI) to derive the Temperature Vegetation Drought Index (TVDI) and investigate its correlations with topography and climatic factors in the western Qaidam Basin. For this study, data were obtained from a variety of sources. Digital elevation model (DEM) data and Moderate Resolution Imaging Spectroradiometer (MODIS) products were obtained from NASA (National Aeronautics and Space Administration). In addition, data from meteorological station were collected from the Resource and Environment Science Data Centre to obtain meteorological information for the study area. The study revealed the following: 1) The areas studied show a concentric ring pattern, with higher elevations in the southeast and a low-lying center. Climatic analyzes show that the annual precipitation decreases from southeast to northwest, and the annual evaporation in the inner part of the basin is more than 1,800 mm 2) The LST/NDVI feature space plots show triangular patterns in the dry and wet boundary equation fittings, and the TVDI shows that the central part of the basin is dominated by moderate to severe drought, while the southeastern part is relatively normal and wet. The intensity of drought gradually increased from June to August. 3) The alluvial fans show higher TVDI values in the fan margins; the wind streaks show significantly higher TVDI, indicating greater aridity due to strong winds; and the ring structures formed by tectonic uplift and salt rise have elevated TVDI compared to the surrounding areas. 4) TVDI decreases by 0.12 per 700 m elevation gain, while in the flat, highly arid central basin, TVDI is high but decreases slightly as the increasing slope changes the local microclimate. This study contributes to the understanding of the regional arid environment characteristics of the western Qaidam Basin, and also references the significance of the study of desertification in other extreme arid areas.