Spatial and temporal characteristics of surface albedo in Badain Jaran Desert, China

Abstract

Obtaining surface albedo of high accuracy and analyzing spatial and temporal characteristics are essential for detecting change mechanism and influencing factors of surface albedo in deserts. Surface albedo from the Operational Land Imager (OLI) was assimilated into black-sky short-wave albedo (BSA) with an ensemble Kalman filter (EnKF) algorithm, to retrieve the surface albedo of high accuracy in Badain Jaran Desert. The results show that the average relative error decreases from 14.813% to 8.530% when surface albedo based on OLI is assimilated into BSA with the EnKF, and assimilated value can accurately describe the spatial and temporal distribution of surface albedo. The surface albedo has an obvious seasonal difference and presents a U-shape curve in a year, with the highest albedo in winter and lowest in summer. Owing to snow cover in some high-altitude areas, surface albedo is the highest and the spatial difference reaches maximum (variation coefficient=0.14) in winter. The Structure Similarity in surface albedo increases from the hinterland of desert (0.40–0.70) to the outer areas (0.70–0.90), as dune number decreases and distance between dunes increases. Compared with mobile and semi-mobile dunes, the minimum surface albedo of semi-fixed and fixed dunes postpones one month due to lag effect of the vegetation response to precipitation.