Toward advanced daily cloud-free snow cover and snow water equivalent products from Terra-Aqua MODIS and Aqua AMSR-E measurements
Toward advanced daily cloud-free snow cover and snow water equivalent products from Terra-Aqua MODIS and Aqua AMSR-E measurements
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DOI：
10.1016/j.jhydrol.2010.01.022
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发表时间：
2010-05
影响因子：
6.4
通讯作者：
Yang Gao;H. Xie;Ning Lu;T. Yao;Tiangang Liang
中科院分区：
文献类型：
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作者：
Yang Gao;H. Xie;Ning Lu;T. Yao;Tiangang Liang
利用光学传感器的高空间分辨率和被动微波传感器对云的穿透性，开发了一种利用每日Terra-Aqua中分辨率成像光谱仪(MODIS)和AQUA高级微波扫描辐射计生成每日无云积雪(SC)和雪水当量(SWE)产品的方法，这两种产品均具有500m空间分辨率。这种方法在阿拉斯加费尔班克斯和上苏西特纳山谷地区进行了为期一年的水文测试(2006年10月至2007年9月)。结果表明，在无云条件下，每日MODIS产品和Terra-Aqua MODIS组合产品具有相似的高分类精度(91%~94%)，日组合产品可使云量∼减少10%。结果还表明，新的SC产品的积雪准确率为86%，远远高于Terra、Aqua和Terra/Aqua组合积雪产品(在所有天气条件下)的31%、45%和49%。验证结果表明，AMSR-E SWE产品的准确率为68.5%，存在高估SWE的倾向。基于AMSR-E像元的亚像素分析对SWE进行重新分布，不仅产生了更高空间分辨率的新产品，现在更适合于流域和区域监测和建模，而且还略微提高了SWE估计的精度。该方法也可用于AVHRR、LANDSAT等其他光学数据与SSMR、SSM/I等无源微波数据的融合，以及未来的NPP和NPOESS任务。
By taking advantage of the high spatial resolution of optical sensors and cloud penetration of a passive microwave sensor, a method is developed to generate new daily cloud-free snow cover (SC) and snow water equivalent (SWE) products, both in 500m spatial resolution, utilizing daily Terra–Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) and Aqua Advanced Microwave Scanning Radiometer for NASA’s Earth Observing System (AMSR-E) snow products. This method was tested in Fairbanks and Upper Susitna Valley, Alaska area for one hydrological year (October 2006–September 2007). The results confirm that daily MODIS products and Terra–Aqua MODIS combined products have similar and high classification accuracy (91–94%) in cloud-free conditions and that the daily combination can reduce cloud cover ∼10%. The results also show the snow accuracy of the new SC products is 86%, which is much higher than the 31%, 45%, and 49% of the Terra, Aqua, and Terra/Aqua combined snow cover products (in all weather conditions), respectively. The validation demonstrates that the accuracy of AMSR-E SWE products is 68.5% and they tend to overestimate SWE. Redistribution of SWE, based on sub-pixel analysis of AMSR-E pixels, not only generates the new product at higher spatial resolution, now more suitable for basin and regional monitoring and modeling, but also slightly increases the accuracy of the SWE estimations. This method can also be used in merging other optical data such as AVHRR, Landsat with passive microwave data such as SSMR, SSM/I, and for future NPP and NPOESS missions.