Accuracy evaluation and analysis of MODIS snow cover products in typical snow cover areas of China
MODIS V6 no longer provides binary and fractional snow cover products,but only gives the Normal-ized Difference Snow Index(NDSI)of pixels.Therefore,when snow mapping based on MODIS V6,the selec-tion of NDSI threshold and the corresponding snow mapping accuracy need to be studied.In this paper,based on the daily measured snow depth data of 250 ground meteorological stations from 2013 to 2021,we evaluate the NDSI_Snow_Cover band in 1927 scenes of MOD10A1 and 1936 scenes of MYD10A1 images in three typi-cal snow cover areas in China.The optimal accuracy and corresponding optimal NDSI threshold of station-by-station pixels in snow cover product mapping were calculated respectively,and the factors affecting the accuracy were analyzed.The evaluation results based on station snow depth show that:(1)The mean±standard devia-tion of the optimal NDSI thresholds of MOD10A1 and MYD10A1 were 0.16±0.09 and 0.17±0.10,respective-ly.The mean±standard deviation of the corresponding OA,FS and CK were 0.96±0.05 and 0.94±0.05,0.84±0.19 and 0.75±0.24,0.81±0.20 and 0.71±0.24,respectively.The accuracy of MOD10A1 was better than that of MYD10A1.(2)The optimal accuracy of MODIS snow cover products has obvious spatial heterogeneity.The accuracy in the Qinghai-Xizang Plateau is much smaller than that in the Northeast-Inner Mongolia region and the northern Xinjiang region.(3)In the station-based snow mapping accuracy evaluation,the threshold of snow depth will affect the evaluation results.The accuracy of snow mapping was the highest when the snow depth threshold of 2 cm and 4 cm was used to evaluate MOD10A1 and MYD10A1.(4)SCO and SDI have a sig-nificant positive correlation with CK of MOD10A1 and MYD10A1,and the correlation coefficients were 0.72 and 0.77,0.67 and 0.71,respectively.(5)The terrain of the Qinghai-Xizang Plateau is complex,and the snow is mainly light snow.The snow information of the stations cannot represent the pixels well.Therefore,it is better to use synchronous UAV observation or higher resolution remote sensing images to evaluate the accura-cy of snow cover products on the Qinghai-Xizang Plateau.
万方数据
维普
