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结合Terra和Aqua卫星的积雪产品,获取2001～2008年东北—内蒙古地区逐年积雪日数分布,并利用此数据对比Terra卫星积雪数据获取的逐年积雪日数。结果表明随海拔的升高,双星与单颗卫星积雪日数差异呈现明显增加的趋势。整个东北—内蒙古地区双星积雪日数平均高出单颗卫星积雪日15 d,但与台站积雪日数对比发现,双星积雪日数平均仍然偏低27 d。这说明,利用Terra和Aqua双卫星积雪监测数据能明显改善山区云对遥感监测的影响,同时也可以减少降雪初期和消融期由于积雪消融较快带来的积雪漏测,但不足以消除云等因素的影响。考虑到获取的2001～2006年台站年积雪日数与MODIS年积雪日数与有良好的统计关系,利用两者建立的线性统计关系修正整个东北—内蒙古地区的MODIS积雪日数,能够很好地消除云等因素带来的MODIS双卫星积雪日数偏小的问题,修正后台站与双星积雪日数之间的绝对误差由原来的27 d减小到18 d。“,”New snow cover product is produced by the combined using of MODIS Aqua and Terra snow cover products from 2001 to 2008.Then two sets of MODIS snow covered days are produced by the using of new snow cover products and Terra/MODIS snow cover products.Through comparison of this two different snow covered days in North Eastern and Inner Mongolia region,it indicates that the differences of snow covered days between these two sets of data are growing with the rising of elevation.The differences between these two sets of data are about 15 days in average.Although the combined use of Terra and Aqua products can generate more snow covered days,the combined data still lower than insitu observations of snow covered days about 27 days.Since the combined snow covered days smaller than insitu observations,but with a good regression relationship,which means calibration of MSCD image could significantly improve its precision status in those regions.After the calibration of MSCD based on insitu observations,the difference between insitu SCD and calibrated MSCD are reduced from 27 days to 18d.