Terra and Aqua MODIS have successfully operated for more than 20 and 18 years, respectively, and far exceeded their designed lifetimes of 6 years. MODIS has 36 spectral bands, among which 16 are the thermal emissive bands (TEB) covering a wavelength range from 3.75 to 14.24 μm. Observations from the MODIS TEB have been used to generate a number of data products, such as surface/cloud/atmospheric temperatures, cloud top altitude, and water vapor properties. To a large extent, the quality of the MODIS L1B radiance product has been maintained through the entirety of each mission via extensive on-orbit calibration and validation efforts. MODIS TEB calibration uses a quadratic algorithm and is referenced to an on-board blackbody with its temperature measurements traceable to the NIST standard. We provide an overview of the MODIS instrument operations, key TEB calibration activities, and algorithms used in the latest L1B data Collection 6.1 (C6.1) and describe the TEB on-orbit performance for both Terra and Aqua MODIS. The TEB gain trends have been stable to within 5% over the Terra mission after 2003 under the same electronic configuration, except for bands 27 to 30, and within 3% over the Aqua mission. The Terra MODIS optical crosstalk correction implemented right after launch has been very effective in removing the ghost images in its photoconductive detector bands 32 to 36. Starting from C6.1, an electronic crosstalk correction algorithm has also been applied to the Terra MODIS photovoltaic detector long-wave infrared bands 27 to 30. The noise characterization performance remains stable with most TEB detectors continuously meeting their design requirements. A gradual loss of the Aqua MODIS radiative cooler margin reached its maximum in 2013 and has been slowly recovering since then. On-orbit changes in TEB response versus scan angle are extremely small based on pitch maneuver observations and assessments using vicarious approaches. The remaining challenges in TEB calibration and proposed improvements for the upcoming data collection with L1B data production and reprocessing are discussed.

中文翻译：

---

Terra和Aqua MODIS热发射带的在轨校准和性能评估

Terra和Aqua MODIS分别成功运行了20多年和18年，远远超过了其6年的设计寿命。MODIS具有36个光谱带，其中16个是热发射带（TEB），覆盖3.75至14.24μm的波长范围。来自MODIS TEB的观测已用于生成许多数据产品，例如地表/云/大气温度，云顶高度和水蒸气性质。在很大程度上，通过广泛的在轨校准和验证工作，在每次任务的整个过程中都保持了MODIS L1B辐射产品的质量。MODIS TEB校准使用二次算法，并且参考板载黑体，其温度测量值可追溯到NIST标准。我们提供了MODIS仪器操作的概述，主要的TEB校准活动，以及最新的L1B数据收集6.1（C6.1）中使用的算法，并描述了Terra和Aqua MODIS的TEB在轨性能。除27至30频段外，在相同的电子配置下，2003年之后，Terra任务的TEB增益趋势稳定在5％以内，Aqua任务的TEB增益趋势在3％以内。发射后立即实施的Terra MODIS光学串扰校正非常有效地消除了其光电导检测器带32至36中的重影。从C6.1开始，电子串扰校正算法也已长期应用于Terra MODIS光伏检测器-红外波段27至30。大多数TEB探测器不断满足其设计要求时，噪声表征性能保持稳定。Aqua MODIS辐射冷却器余量的逐渐损失在2013年达到最高，自那时以来一直在缓慢恢复。基于俯仰操纵观测和使用替代方法的评估，TEB响应相对于扫描角度的在轨变化非常小。讨论了TEB校准中的其余挑战，以及通过L1B数据生成和重新处理为即将到来的数据收集建议的改进。