Publications

Xu, ER; Zhang, HQ (2022). A stratified environmental reference system for better understanding of the relationship between remote sensing observations and ground monitoring of karst rocky desertification. LAND DEGRADATION & DEVELOPMENT, 33(9), 1366-1382.

Abstract
Quickly and accurately monitoring karst rocky desertification via remote sensing could assist in its mitigation. Yet this is limited by high environmental heterogeneity that introduces uncertainty into satellite observations' relationships with ground-based karst rocky desertification. Influenced by variations of environmental factors, the relevance of satellite data for karst rocky desertification is questionable, especially at a large geographic scale. Here a novel stratified degradation reference system was built to describe this complex relationship. The method was applied in Guizhou-Guangxi Karst Mountainous Region, a typical karst region in China undergoing severe karst rocky desertification. A stratified procedure of elevation-based initial division and sub-division of lithology and land use was designed using moderate resolution imaging spectroradiometer (MODIS) data. MODIS values of surface vegetation, albedo, and temperature products were standardized by percentiles to reveal their relevance for evaluating each environmental stratification of land degradation. We found a substantial spatial variation of MODIS observations across elevation gradients and different land uses. This was corrected using our proposed reference method, wherein standardized MODIS observations show a nonlinear but clear downward trend with increasing karst rocky desertification intensities. Most areas affected by karst rocky desertification had lower MODIS values. Using the stratified environmental reference approach between MODIS observations and karst rocky desertification can enable the cost-effective screening of high-heterogeneity karst areas, to better support monitoring and identify desertification hotspots.

DOI:
10.1002/ldr.4232

ISSN:
1099-145X