Barnes R A, Eplee R E, Schmidt G M, Patt F S, McClain C R
Science Applications International Corporation, Beltsville, Maryland 20705, USA.
Appl Opt. 2001 Dec 20;40(36):6682-700. doi: 10.1364/ao.40.006682.
We present an overview of the calibration of the Sea-viewing Wide Field-of View Sensor (SeaWiFS) from its performance verification at the manufacturer's facility to the completion of its third year of on-orbit measurements. These calibration procedures have three principal parts: a prelaunch radiometric calibration that is traceable to the National Institute of Standards and Technology; the Transfer-to-Orbit Experiment, a set of measurements that determine changes in the instrument's calibration from its manufacture to the start of on-orbit operations; and measurements of the sun and the moon to determine radiometric changes on orbit. To our knowledge, SeaWiFS is the only instrument that uses routine lunar measurements to determine changes in its radiometric sensitivity. On the basis of these methods, the overall uncertainty in the SeaWiFS top-of-the-atmosphere radiances is estimated to be 4-5%. We also show the results of comparison campaigns with aircraft- and ground-based measurements, plus the results of an experiment, called the Southern Ocean Band 8 Gain Study. These results are used to check the calibration of the SeaWiFS bands. To date, they have not been used to change the instrument's prelaunch calibration coefficients. In addition to these procedures, SeaWiFS is a vicariously calibrated instrument for ocean-color measurements. In the vicarious calibration of the SeaWiFS visible bands, the calibration coefficients are modified to force agreement with surface truth measurements from the Marine Optical Buoy, which is moored off the Hawaiian Island of Lanai. This vicarious calibration is described in a companion paper.
我们概述了海景宽视场传感器（SeaWiFS）从在制造商工厂进行性能验证到完成在轨测量的第三年期间的校准情况。这些校准程序主要有三个部分：可追溯到美国国家标准与技术研究院的发射前辐射校准；转移到轨道实验，这是一组用于确定仪器从制造到在轨运行开始期间校准变化的测量；以及对太阳和月球的测量，以确定在轨辐射变化。据我们所知，SeaWiFS是唯一使用常规月球测量来确定其辐射灵敏度变化的仪器。基于这些方法，SeaWiFS大气层顶辐射的总体不确定度估计为4 - 5%。我们还展示了与机载和地面测量的比对活动结果，以及一个名为南大洋8波段增益研究的实验结果。这些结果用于检查SeaWiFS各波段的校准情况。到目前为止，它们尚未用于更改仪器的发射前校准系数。除了这些程序外，SeaWiFS还是一种用于海洋颜色测量的间接校准仪器。在对SeaWiFS可见波段的间接校准中，校准系数会被修改，以使其与停泊在夏威夷拉奈岛附近的海洋光学浮标的地表真值测量结果达成一致。这种间接校准在一篇配套论文中有描述。
