Karst regions in southwest China are in the central karst geomorphology of eastern Asia and are one of the largest karst areas in the world. For the actively biological and chemical processes of CO2-H2O-CaCO3 system, karst regions are typically ecological fragile zones constrained by geological setting and have been reported to possess severe rocky desertification, following sandy desertification in northwest China, and soil and water loss in the Loess Plateau, is considered to be one of the most dangerous ecological and environmental problems in China. Because of the inherent merits of macro scale, frequency, efficiency, and synthesis, remote sensing was the promising method to monitor and assess karst rocky desertification. The traditional remote-sensing methods mostly focused on visual interpretation, with high subjectivity and low efficiency.

For accurate extraction of karst rocky desertification information, Dr. Yuemin Yue, directed by Prof. Kelin Wang of Institute of Subtropical Agriculture, CAS, and Prof. Bing Zhang of Center for Earth Observation and Digital Earth, CAS, built the spectra database and identified the spectral features of karst ground objects. They also firstly proposed a new spectral index model—KRDSI (karst rocky desertification synthesis index) to extract the fractional cover of exposed bedrock, bare soil and non-photosynthesis vegetation based on mixed-spectral absorption features of karst ground objects. KRDSI could be used to directly and accurately extract the ractional cover of exposed bedrock, bare soil and non-photosynthesis vegetation. This study indicates that hyperspectral remote sensing imagery (e.g. EO-1 Hyperion) could be used to directly extract evaluation indicators of karst rocky desertification with the combination of vegetation indices and KRDSI.

This study provides novel methods and theories for remotely sensed monitoring karst rocky desertification and reduces the dependences on visual interpretation. It could also promote the automatic operation of remotely sensed monitoring of karst rocky desertification.

The results of this study have been published in the famous journal of International Journal of Remote Sensing (2010, 31(8), 2115-2122).