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Model Development for MODIS Thermal Band Electronic CrosstalkMODerate-resolution Imaging Spectroradiometer (MODIS) has 36 bands. Among them, 16 thermal emissive bands covering a wavelength range from 3.8 to 14.4 m. After 16 years on-orbit operation, the electronic crosstalk of a few Terra MODIS thermal emissive bands developed substantial issues that cause biases in the EV brightness temperature measurements and surface feature contamination. The crosstalk effects on band 27 with center wavelength at 6.7 m and band 29 at 8.5 m increased significantly in recent years, affecting downstream products such as water vapor and cloud mask. The crosstalk effect is evident in the near-monthly scheduled lunar measurements, from which the crosstalk coefficients can be derived. The development of an alternative approach is very helpful for independent verification.In this work, a physical model was developed to assess the crosstalk impact on calibration as well as in Earth view brightness temperature retrieval. This model was applied to Terra MODIS band 29 empirically to correct the Earth brightness temperature measurements. In the model development, the detectors nonlinear response is considered. The impact of the electronic crosstalk is assessed in two steps. The first step consists of determining the impact on calibration using the on-board blackbody (BB). Due to the detectors nonlinear response and large background signal, both linear and nonlinear coefficients are affected by the crosstalk from sending bands. The second step is to calculate the effects on the Earth view brightness temperature retrieval. The effects include those from affected calibration coefficients and the contamination of Earth view measurements. This model links the measurement bias with crosstalk coefficients, detector non-linearity, and the ratio of Earth measurements between the sending and receiving bands. The correction of the electronic cross talk can be implemented empirically from the processed bias at different brightness temperature. The implementation can be done through two approaches. As routine calibration assessment for thermal infrared bands, the trending over select Earth scenes is processed for all the detectors in a band and the band averaged bias is derived at a certain time. In this case, the correction of an affected band can be made using the regression of the model with band averaged bias and then corrections of detector differences are applied. The second approach requires the trending for individual detectors and the bias for each detector is used for regression with the model. A test using the first approach was made for Terra MODIS band 29 with the biases derived from long-term trending of brightness temperature over ocean and Dome-C.
Document ID
20170008487
Document Type
Conference Paper
External Source(s)
Authors
Chang, Tiejun (Science Systems and Applications, Inc. Lanham, MD, United States)
Wu, Aisheng (Science Systems and Applications, Inc. Lanham, MD, United States)
Geng, Xu (Science Systems and Applications, Inc. Lanham, MD, United States)
Li, Yonghonh (Science Systems and Applications, Inc. Lanham, MD, United States)
Brinkman, Jake (Science Systems and Applications, Inc. Lanham, MD, United States)
Keller, Graziela (Science Systems and Applications, Inc. Lanham, MD, United States)
Xiong, Xiaoxiong (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
September 5, 2017
Publication Date
October 19, 2016
Publication Information
Publication: Sensors, Systems, and Next-Generation Satellites XX
Volume: 10000
ISSN: 0277-786X
Subject Category
Earth Resources and Remote Sensing
Instrumentation and Photography
Report/Patent Number
GSFC-E-DAA-TN46049
Meeting Information
SPIE Remote Sensing Conference 2016(Edinburgh)
Funding Number(s)
CONTRACT_GRANT: NNG15HQ01C
Distribution Limits
Public
Copyright
Other