Spatial Relationships between Topographic Variables and Their Interactions with Natural and Climatic Zonalization in Mongolia

Abstract

The main objective of this investigation is to examine the spatial relationship between the topographic variables in Mongolia, which is important in the pattern of regional relief, geomorphological regionalization, and natural zonalization. For the analysis, we used seven different terrain parameters such as elevation, slope, aspect, topographic position index (TPI), topographic wetness index (TWI), latitude, and longitude. Five of seven variables were obtained from a digital elevation model (DEM) of the Shuttle Radar Topography Mission (SRTM) at a spatial resolution of 30 m. The location of the latitude and longitude were extracted from the central point of the gridded vector data. The correlation analysis of seven topographic variables showed that the highest positive correlation (r=0.55) was detected between elevation and slope. In contrast, the highest negative correlation (r=-0.63) was detected between elevation and longitude. The lowest correlations were detected between the aspect and the remaining six variables. The significance levels of elevation, slope, latitude, longitude, and TWI noted p < 0.0001 for each pair of variables. The correlation between aspect and TPI ranged p < 0.01 while elevation and aspect, latitude and TPI, and longitude and TPI ranged p < 0.1, respectively. The corresponding frequency distributions are characterized by three left skew, two bimodal, and two normal distributions, respectively. We also examined the contribution of the topographic variables to natural and climatic zonalization in Mongolia. The result confirmed that topographic variables were key indicators for identifying regional differences in physical geographic regionalization, and natural and climatic zonalization. The examination of topographic variables allowed more knowledge of geographic characteristics. At the same time, the result is of great value in the investigation of natural geographic divisions, and regional nature conservation research.