Moderate Resolution Imaging Spectroradiometer on Terra: limitations for ocean color applications
Moderate Resolution Imaging Spectroradiometer on Terra: limitations for ocean color applications
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DOI：
10.1117/1.2957964
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发表时间：
2008-01-01
影响因子：
1.7
通讯作者：
McClain, Charles R.
中科院分区：
文献类型：
--
作者：
Franz, Bryan A.;Kwiatkowska, Ewa J.;McClain, Charles R.
中分辨率成像光谱仪目前正在Terra和Aqua卫星平台上飞行。美国航天局戈达德空间飞行中心的海洋生物学处理小组正在利用MODIS-Aqua传感器制作实用的海洋颜色产品;然而，在发射前和在轨定性方面有文件记录的不确定性和不稳定性妨碍了利用MODIS-Terra制作类似产品。特别是，412纳米波段的辐射响应在7年的飞行使命中下降了40%以上，在较长波长中也有类似但不太极端的变化。虽然这种可变性可以通过机载校准系统完全校正，但这表明扫描镜的光学特性自发射以来发生了显著变化。此外，退化趋势在反射镜两侧之间有很大不同，这可能是发射前测试期间对反射镜造成的不对称损坏的结果。这些影响导致我们对仪器响应与反射镜上的入射角和所观察到的辐射的偏振的灵敏度的知识的不确定性。在本文中，我们研究了明显的MODIS-Terra仪器表征误差对派生的海洋颜色产品的影响，并表明，在当前的操作校准的残余误差引起显着的交叉扫描文物，镜边的差异，探测器到探测器条纹在检索的离水辐射。此外，我们描述了OBPG努力减少这些文物通过统计和替代仪器表征，并显示质量的水离开辐射检索相对于那些来自MODIS-Aqua。
The Moderate Resolution Imaging Spectroradiometer (MODIS) is currently flying on both the Terra and Aqua satellite platforms. The Ocean Biology Processing Group (OBPG) at NASA Goddard Space Flight Center is producing operational ocean color products from the MODIS-Aqua sensor; however, documented uncertainties and instabilities in the prelaunch and on-orbit characterization have inhibited the production of similar products from MODIS-Terra. In particular, the radiometric response of the 412-nm band has degraded by more than 40% over the 7-year mission lifespan, with similar though less extreme changes in the longer wavelengths. While such variability may be fully correctable through the on-board calibration system, it suggests that the optical properties of the scan mirror have changed significantly since launch. Furthermore, the degradation trends are substantially different between the two mirror sides, which is likely a result of asymmetric damage done to the mirror during prelaunch testing. These effects contribute to uncertainty in our knowledge of instrument response versus incidence angle on the mirror and sensitivity with respect to polarization of the observed radiance. In this paper, we examine the impact of apparent MODIS-Terra instrument characterization errors on the derived ocean color products and show that residual errors in the current operational calibration give rise to significant cross-scan artifacts, mirror-side differences, and detector-to-detector striping in the retrieved water-leaving radiances. In addition, we describe OBPG efforts to reduce these artifacts through statistical and vicarious instrument characterization, and show the quality of the resulting water-leaving radiance retrievals relative to those derived from MODIS-Aqua.