| Autor: |
Yu, Fangfang, Shao, Xi, Wu, Xiangqian, Takahashi, Masaya, Okuyama, Arata |
| Rok vydání: |
2016 |
| Zdroj: |
Conference on Characterization and Radiometric Calibration for Remote Sensing (CALCON) |
| Popis: |
The Moon, due to its inherent reflectance stability and negligible atmosphere effect, has been used as a solar diffuser for the satellite instrument radiometric calibration in the solar reflective wavelength. Currently the lunar disk-equivalent irradiance is most commonly used to trend the instrument on-orbit degradation. Yet the accurate observation and simulation of the lunar irradiance are greatly challenged with the changes in lunar phase and libration. This is especially the case for the geostationary weather instruments in which the lunar image are obtained at any phase angles when the Moon appear within the instrument field of regard. Alternatively one can use lunar radiance at selected uniform sites as calibration reference, provided that the viewing and illuminating geometric effects at these sites can be well characterized. Two key techniques have been identified toward the site characterizations for the lunar radiance model development: relatively uniform site selections and auto-coregistration of satellite images for radiance extraction. NOAA recently has identified a set of spectrally and geospatially relatively uniform sites based on the high spectral and spatial resolution measurements of Japan Aerospace Exploration Agency (JAXA) lunar orbital SELENE instruments. Japan Meteorological Agency (JMA) Himawari-8 Advanced Himawari Imager (AHI), which has a very similar optical design as GOES-R Advanced Baseline Imager (ABI), has already acquired substantial lunar images since its launch in October 2014. These lunar images provide an opportunity to develop an accurate lunar radiance model for the radiometric calibration validation of new generation of GEO instruments. In this study, we evaluate the selected lunar targets with the Himawari-8 AHI data. Our early results from one AHI lunar-tracing event images show apparent bidirectional reflectance function (BRDF) effect at the selected sites. Effort and progress to characterize the BRDF effects at the selected sites will be reported in the coming meeting. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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