Land degradation monitoring using time-series MODIS and TM data

Land degradation is one of the serious environmental problems that can lead to poverty. North Hebei province is one part of eco-fragile region in North China, and is a transitional zone from farming to forest and grassland. This paper evaluated land degradation of North Hebei province from 1987 to 2001. Remote sensing data were time-series MODIS 500m 8-day surface reflectance and 16-day EVI product in 2001 and Landsat TM data in 1987 and 2000. TM and MODIS data were processed in ERDAS and ModisTool software including projection transformation and subset. Degradation evaluation indices, including enhanced vegetation index (EVI), land surface water index (LSWI) and modified soil adjusted vegetation index (MSAVI) of three subregions were calculated. Results showed that the total land degradation area was 64439km2 in 2001, of which high and severe land degradation level area were 20734km2 and 3948km2, accounting for 32.18% and 6.13%, respectively. Low land degradation level appeared in Yanshan mountainous area; medium land degradation level mainly appeared in Bashang plateau region, where vegetation types were cultivated land and grassland, and high land degradation level mainly appeared in Bashang plateau region and the basin area, where grass land degradation and soil erosion were serious.