| タイトル | MODIS Solar Diffuser On-Orbit Degradation Characterization Using Improved SDSM Screen Modeling |
| 本文（外部サイト） | http://hdl.handle.net/2060/20170004618 |
| 著者（英） | Xiong, Xiaoxiong; Angal, Amit Avinash; Chen, H.; Wu, A.; Wang, Z. |
| 著者所属（英） | NASA Goddard Space Flight Center |
| 発行日 | 2016-09-26 |
| 言語 | eng |
| 内容記述 | The Solar Diffuser (SD) is used for the MODIS reflective solar bands (RSB) calibration. An on-board Solar Diffuser Stability Monitor (SDSM) tracks the degradation of its on-orbit bi-directional reflectance factor (BRF). To best match the SDSM detector signals from its Sun view and SD view, a fixed attenuation screen is placed in its Sun view path, where the responses show ripples up to 10%, much larger than design expectation. Algorithms have been developed since the mission beginning to mitigate the impacts of these ripples. In recent years, a look-up-table (LUT) based approach has been implemented to account for these ripples. The LUT modeling of the elevation and azimuth angles is constructed from the detector 9 (D9) of SDSM observations in the MODIS early mission. The response of other detectors is normalized to D9 to reduce the ripples observed in the sun-view data. The accuracy of all detectors degradation estimation depends on how well the D9 approximated. After multiple years of operation (Terra: 16 years; Aqua: 14 years), degradation behavior of all detectors can be monitored by their own. This paper revisits the LUT modeling and proposes a dynamic scheme to build a LUT independently for each detector. Further refinement in the Sun view screen characterization will be highlighted to ensure the degradation estimation accuracy. Results of both Terra and Aqua SD on-orbit degradation are derived from the improved modeling and curve fitting strategy. |
| NASA分類 | Earth Resources and Remote Sensing |
| レポートNO | GSFC-E-DAA-TN42647 |
| 権利 | Copyright, Distribution as joint owner in the copyright |
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