青藏高原Soumi-NPP和MODIS积雪范围产品的对比分析

Soumi-NPP（Soumi Polar-orbiting Partnership）卫星作为接替服役超期的Terra、Aqua卫星，其积雪范围产品在青藏高原的精度尚未被评价。以Soumi-NPP积雪范围产品为研究对象，利用气象台站点数据并结合更高分辨率的Landsat-8 OLI数据，评价该产品的精度，并与MODIS（Moderate Resolution Imaging Spectroradiometer）积雪范围产品进行对比分析。结果表明：使用气象台站进行数据验证时，NPP、MOD与MYD三种积雪范围产品的总精度均较高，但三者积雪漏分误差都较大，其中MYD的漏分误差最大，为64.2%；当雪深小于5 cm时，三种积雪范围产品的积雪分类精度都较低，雪深大于等于5 cm时，NPP积雪范围产品的积雪分类精度最高，为82.3%，MOD与MYD的精度分别为77.1%和69.4%；利用Landsat-8 OLI数据验证时，Soumi-NPP积雪范围产品的Kappa系数最高，其均值为0.707，为高度一致性。而MOD10A1与MYD10A1的Kappa系数较低，分别为0.476与0.557，为中等一致性；Soumi-NPP积雪范围产品的Kappa系数大多在0.6以上，精度比较稳定，而MODIS积雪范围产品的Kappa系数波动较大，精度稳定性较差。Soumi-NPP积雪范围产品相较于MODIS积雪范围产品，其精度有了较大的提升，为准确监测青藏高原积雪范围提供了一个更优的选择。

Comparative analysis of the snow coverage products of Soumi-NPP and MODIS in the Qinghai-Tibet Plateau

The Soumi Polar-orbiting Partnership (Soumi-NPP) satellites have served as replacement of Terra and Aqua satellites. The accuracy of its snow coverage products on the Qinghai-Tibet Plateau has not yet been evaluated. In this study, the meteorological station data and higher resolution data of Landsat-8 OLI are used to evaluate the accuracy of the Soumi-NPP and MODIS snow coverage product. The results show that the total accuracy of the three snow coverage products, NPP, MOD10A1 and MYD10A1, are all higher when the observation is using to verify, but the errors of the three snow coverage products are all large, and the omission error of MYD, 64.2%, is the largest. The snow classification accuracy of the three snow coverage products is low when the snow depth is lower than 5 cm, and the snow classification accuracy of NPP snow coverage product is the highest, which is 82.3% when the snow depth is greater than 5 cm, and those of MOD10A1 and MYD10A1 are 77.1% and 69.4%, respectively. The Kappa coefficient of Soumi-NPP snow coverage product is the highest, 0.707 in average, which is highly consistent with Landsat-8 OLI data. The Kappa coefficients of MOD10A1 and MYD10A1 are 0.476 and 0.557, respectively. The Kappa coefficients of the two MODIS snow coverage products have moderately consistency with that of Landsat-8 OLI data. The Kappa coefficients of Soumi-NPP are above 0.6 mostly, with the accuracy relatively stable, while the Kappa coefficient of the MODIS snow coverage fluctuates greatly, with poor accuracy stability. To sum up, compared with MODIS snow coverage product, the accuracy of Soumi-NPP snow coverage product has been greatly improved, which may be a better choice for accurately monitoring the snow-coverage of the Qinghai-Tibet Plateau.