Authors: Bo Xu*, California State University, San Bernardino
Topics: Earth Science, Remote Sensing
Keywords: cockpit karst; topography; vegetation; NDVI; scale
Session Type: Paper
Presentation File: No File Uploaded
Literature in remote sensing shows that the study of the relationship between topography and vegetation is often conducted in large mountainous areas where topographic attributes vary significantly, and a multi-scale approach is applied in which the investigation gradually downscaled to coarser spatial resolutions. Little such research has been done in a typical cockpit karst area where the topographic properties usually don’t exhibit significant variations and lower resolution data cannot be utilized for a small area like cockpit karst. This paper proposes an innovative approach to examine the correlations between topography and vegetation in a tropical (Ciales, Puerto Rico, USA) and a subtropical (Maolan, Guizhou, China) cockpit karst area. Topographic profiles were first constructed over individual karst residual hills at an azimuth increment of 22.5 degrees. The paired values of elevation and NDVI along the profiles were then extracted and correlation analysis were performed. The results indicate that significantly more profiles present high negative correlations between elevation and NDVI values, which could be attributed to the variations in moisture source resulting from the singular hydrogeological characteristics in cockpit karst areas. Slope aspect also shows its influences on vegetation. More south-facing profiles exhibit high negative correlations than north-facing profiles in the subtropical Maolan area. However, the difference is not statistically significant in the tropical Coals area, where variations in evapotranspiration between south-facing and north-facing slopes are not as significant as those in the subtropical karst areas.