Spatial and Temporal Variations of Land Surface Albedo and Its Influencing Factors Based on MODIS Data

The surface albedo represents the ability of the earth’s surface to reflect solar radiation and is a key parameter that affects the balance of surface radiation energy. Based on moderate resolution imaging spectroradiometer (MODIS) data, spatial and temporal variations of the land surface albedo and the influence of the types of land use, terrain, land surface parameters, and climate factors in the Huaihe River basin from 2005 to 2015 were analyzed using grid trend, abnormal change, correlation, and gray correlation analyses. The results show that the annual average land surface albedo of the Huaihe River basin displayed a spatial distribution pattern of “high in the north and east, low in the south and west”, varying from 0.043–0.223 with an average of 0.145. Low-value areas were mainly concentrated in regions where water is densely distributed, mountainous and hilly areas, and with a small standard deviation. High-value areas were mainly concentrated in the central and eastern plain of the basin with a relatively large standard deviation. The land surface albedo showed an increasing trend with seasonal differences in 61.5% of the area. The largest was in summer, followed by spring, and finally by autumn. In winter, the fluctuation range is larger owing to the impact of snow cover and farmland use mode. The land surface albedo positively correlated with the NDVI(Normalized Difference Vegetation Index), LST(Land Surface Temperature), air temperature, and precipitation in most areas of Huaihe River Basin, accounting for 90.23%, 82.32%, 85.41%, and 93.70%, respectively. Under different types of land use (except water), the order of the annual average gray correlation degree between the land surface albedo and the influencing factors are as follows: NDVI>air temperature>LST>precipitation, and the order of the spatial gray correlation degree is: NDVI> precipitation >LST> air temperature> elevation.