Dust detection using remotely sensed measurements has been one of the challenging problems encountered by atmospheric scientists. MODerate Resolution Imaging Spectroradiometer (MODIS) on the Terra (T) and Aqua (A) platforms have been a versatile sensor for well over 21 and 18 years respectively, and have been extremely useful in the retrieval of aerosol information over the entire globe. The MODIS radiances from the Level 1B in general are expected to be within 5% accuracy in the reflective wavelengths and within 1% in the thermal emissive wavelengths. In this paper, we evaluate the sensitivity of previously developed dust detection technique based on thermal emissive wavelengths, which correspond to MODIS bands 20, 29, 31, and 32 respectively. The Thermal Emissive Dust Index (TEDI) performed very comparably to the traditional Aerosol Optical Thickness (AOT) retrievals by MODIS reflective channels. Since the MODIS Thermal Emissive Bands (TEB) are well calibrated on-orbit using a BlackBody (BB) source, the calibration of these long wave infrared bands is quite robust. As A-MODIS continues to perform well beyond its designed lifetime of 6 years, the instrument has undergone various levels of degradation during its mission time. As a consequence, it is imperative to check the impacts of calibration on the higher-level retrievals. In this paper, we rigorously analyze the sensitivity of TEDI due to the impact of calibration by the afore-mentioned TEB. The perturbation of the dominant (linear) calibration term demonstrated the following: first, there was a correlation in the sensitivity of the TEDI due to the uncertainty in the linear calibration term. Based on a perturbation in the linear calibration term for all aforementioned bands over a range of ±5% yielded the TEDI sensitivity to vary from approximately −3.2% to about −3.6%. When considering the uncertainty in each individual band significant changes were observed. The least change was observed for the perturbation in the calibration of band 20 with the TEDI sensitivity and the largest sensitivity in TEDI was observed in the perturbation of band 31 calibration. Thus, in the case of TEDI, noticeable sensitivity due to calibration uncertainty was observed in bands 29, 31, and 32, reiterating the importance of the TEB calibration in these bands. Also, the dust detection scheme based on A-MODIS was successfully transferred to the follow-on sensors such as Suomi (SNPP) and NOAA 20 (N20) VIIRS. The results presented in this paper would be extremely helpful in understanding impacts of calibration on the higher-level products for both current and future missions based on the MODIS heritage. Finally, the work also identifies the importance of radiometric fidelity in maintaining the accuracy of the dust detection. Results presented will show drastic improvement of the Saharan dust detection after the reduction of the electronic crosstalk in the 8.5 µm channel of T-MODIS.

使用遥感测量进行粉尘检测一直是大气科学家遇到的具有挑战性的问题之一。Terra（T）和Aqua（A）平台上的中等分辨率成像光谱仪（MODIS）分别已成为多功能传感器，使用时间已超过21年和18年，并且在整个地球范围内的气溶胶信息检索中非常有用。通常，级别1B的MODIS辐射在反射波长中的准确度应在5％之内，而在热辐射波长中的准确度应在1％之内。在本文中，我们基于热发射波长（分别对应于MODIS波段20、29、31和32）评估先前开发的灰尘检测技术的灵敏度。通过MODIS反射通道获得的热发射粉尘指数（TEDI）与传统的气溶胶光学厚度（AOT）相当。由于使用BlackBody（BB）源在轨道上对MODIS热发射带（TEB）进行了很好的校准，因此这些长波红外带的校准非常可靠。随着A-MODIS的性能超过其设计的6年使用寿命，该仪器在执行任务期间经历了各种程度的退化。因此，必须检查校准对更高级别检索的影响。在本文中，由于上述TEB的校准影响，我们对TEDI的灵敏度进行了严格的分析。主导（线性）校准项的扰动表明：由于线性校准项的不确定性，TEDI的灵敏度存在相关性。基于线性校准项中所有上述频带在±5％范围内的扰动，TEDI灵敏度从大约-3.2％到大约-3.6％不等。当考虑每个单独波段的不确定性时，观察到了显着变化。在带TEDI灵敏度的带20的校准中，观察到的扰动变化最小，在带31校准的带扰中，在TEDI中观察到最大的灵敏度变化。因此，对于TEDI，在频段29、31和32中观察到由于校准不确定性引起的显着灵敏度，从而重申了TEB校准在这些频段中的重要性。还，基于A-MODIS的粉尘检测方案已成功转移到Suomi（SNPP）和NOAA 20（N20）VIIRS等后续传感器上。本文介绍的结果对于了解基于MODIS遗产的当前和未来任务的校准对更高级别产品的影响将非常有帮助。最后，这项工作还确定了辐射保真度在保持粉尘检测准确性方面的重要性。呈现的结果将表明T-MODIS 8.5 µm通道中的电子串扰减少后，撒哈拉尘埃探测得到了显着改善。本文介绍的结果对于了解基于MODIS遗产的当前和未来任务的校准对更高级别产品的影响将非常有帮助。最后，这项工作还确定了辐射保真度在保持粉尘检测准确性方面的重要性。呈现的结果将表明T-MODIS 8.5 µm通道中的电子串扰减少后，撒哈拉尘埃探测得到了极大的改善。本文介绍的结果对于了解基于MODIS遗产的当前和未来任务的校准对更高级别产品的影响将非常有帮助。最后，这项工作还确定了辐射保真度在保持粉尘检测准确性方面的重要性。呈现的结果将表明T-MODIS 8.5 µm通道中的电子串扰减少后，撒哈拉尘埃探测得到了显着改善。