Spatial and Temporal Differences in SurfaceAlbedo over Different Underlying Surfacesin the Badain Jaran Desert, China

To study the change mechanism and influencing factors of surface albedo over different underlying surfaces in the Badain Jaran Desert, surface albedo derived from the Operational Land Imager (OLI) was assimilated into black-sky short-wave albedo (BSA) with four-dimensional variational (4DVAR), to retrieve high accuracy surface albedo data. The results indicated that the average relative error decreased by 12.271% when surface albedo based on OLI were assimilated into BSA with 4DVAR, and assimilated value could accurately describe the spatial and temporal distribution of surface albedo. The lag effect in the response of vegetation to precipitation was evident over the semi-fixed and fixed dunes. The surface albedo over the semi-fixed and fixed dunes was lower than that over the shifting and semi-shifting dunes owing to the high surface roughness that increases the reflection of solar radiation. The separation of surface albedo over semi-shifting, semi-fixed, and fixed dunes with patchy distribution were higher than that over shifting dunes owing to the large and continuous distribution, while landscape dominance demonstrated the opposite trend. The difference in monthly perimeter area fractal dimension of surface albedo over shifting dunes was significant owing to the organic matter and sand content while the monthly landscape pattern of surface albedo over fixed dunes was stable.