Abstract. Since its launch in December 1999, Terra Moderate Resolution Imaging Spectroradiometer (MODIS) has successfully operated for more than 20 years, with its observations generating a broad range of science data products that have greatly enabled the remote sensing community and users worldwide in their studies of many key geophysical parameters of the Earth’s systems. MODIS collects data in 36 spectral bands, covering wavelengths from 0.41 to 14.4 μm, which are calibrated by a set of onboard calibrators (OBCs). Also contributing to the sensor’s mission-long on-orbit calibration and characterization are near-monthly scheduled lunar observations and multiple time series of the sensor’s responses over select ground targets at a variety of scan angles. To a large extent, the quality of MODIS data products relies strongly on the dedicated efforts to operate and calibrate the instrument, to derive and update calibration parameters, and to develop and implement new calibration strategies and algorithms in response to on-orbit changes of the sensor’s characteristics and its OBC functions. We provide an overview of the Terra MODIS on-orbit operation and calibration activities over the last 20 years, including changes made to extend and preserve the instrument and OBC functions and their operation strategies. It also illustrates the sensor’s on-orbit performance with results derived from its OBC, lunar observations, and select ground targets and discusses major changes in sensor characteristics and corrections applied to the L1B algorithms as well as calibration lookup table updates. To date, the Terra MODIS instrument and its OBCs continue to operate and function normally. Except for those identified prelaunch, most spectral bands and detectors continue to meet their specified calibration requirements. Also discussed in our paper are lessons learned from Terra MODIS operation and calibration, as well as future efforts to further extend and maintain the quality of its long-term data records.

中文翻译：

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Terra MODIS：20 年的在轨校准和性能

摘要。自 1999 年 12 月推出以来，Terra 中分辨率成像光谱仪 (MODIS) 已成功运行 20 多年，其观测产生了广泛的科学数据产品，极大地促进了全球遥感界和用户的研究地球系统的许多关键地球物理参数。MODIS 收集 36 个光谱带的数据，涵盖从 0.41 到 14.4 μm 的波长，这些数据由一组机载校准器 (OBC) 校准。近月计划的月球观测和传感器在各种扫描角度对选定地面目标的响应的多个时间序列也有助于传感器的长期在轨校准和表征。很大程度上来说，MODIS 数据产品的质量在很大程度上依赖于操作和校准仪器、导出和更新校准参数以及开发和实施新的校准策略和算法以响应传感器特性及其 OBC 的在轨变化的专门努力职能。我们概述了过去 20 年来 Terra MODIS 在轨运行和校准活动，包括为扩展和保留仪器和 OBC 功能及其运行策略所做的更改。它还通过从 OBC、月球观测和选择地面目标得出的结果说明了传感器的在轨性能，并讨论了传感器特性和应用于 L1B 算法的校正以及校准查找表更新的主要变化。迄今为止，Terra MODIS 仪器及其 OBC 继续正常运行和运行。除了在发射前确定的那些，大多数光谱带和探测器继续满足其指定的校准要求。我们的论文还讨论了从 Terra MODIS 操作和校准中吸取的经验教训，以及未来进一步扩展和保持其长期数据记录质量的努力。