Change detection, risk assessment and mass balance of mobile dune fields near Dunhuang Oasis with optical imagery and global terrain datasets

Abstract

ABSTRACT Quantifying the kinematic evolution patterns of dune migration plays a major role in resisting the sand-dust disasters and evaluating the desertification process. With the increment of optical observations, measuring the dune migration with dense spatial and temporal density has become possible. In this study, with the open-accessible Landsat-8 (L8)/Sentinel-2 (S2) imagery and global terrain datasets, we designed a complete workflow of inverting the dune displacement time series and velocity, identifying the potential encroachment risk, and evaluating the sediment balance of mobilized dune fields near Dunhuang Oasis. After the performance of time-series inversion, the standard deviation (STD) of measurements in stable area of raw correlation results was improved by above 40%. The displacement time series and velocity revealed out the spatial heterogeneity and seasonal/inter-annual dynamic evolution of dune migration. Furthermore, dune encroachment risk in the immediate vicinity of local landscapes was evaluated to highlight the unstable dune fields, and the workability of existent sand-control facilities. Additionally, the mass budget of around −0.001 ± 0.025 m/yr shows the stable sediment transport in Mingsha mountain. This study case can be exemplified to lead the risk monitoring and sustainable conservation of Dunhuang region and other places controlled by similar climatic conditions.