Sun beta angle residuals in solar diffuser measurements of the MODIS ocean bands

Gerhard Meister; Junqiang Sun; Robert E. Eplee Jr.; Frederick S. Patt; Xiaoxiong Xiong; Charles R. McClain

doi:10.1117/12.796291

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20 August 2008 Sun beta angle residuals in solar diffuser measurements of the MODIS ocean bands

Gerhard Meister, Junqiang Sun, Robert E. Eplee Jr., Frederick S. Patt, Xiaoxiong Xiong, Charles R. McClain

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Proceedings Volume 7081, Earth Observing Systems XIII; 70810D (2008) https://doi.org/10.1117/12.796291
Event: Optical Engineering + Applications, 2008, San Diego, California, United States

Abstract

The Moderate Resolution Imaging Spectroradiometer (MODIS) on the Earth Observing System (EOS) Aqua platform has 9 spectral bands with center wavelengths from 412nm to 870nm that are used to produce the standard ocean color data products. Ocean color products require a stability of the radiometric calibration on the order of 0.2%, which surpasses the official requirements for the MODIS reflective solar bands. The primary calibration source for the MODIS reflective solar bands is the on-board solar diffuser. For the ocean color bands, the SD calibration is performed with an attenuation screen to prevent saturation. The ocean color products are calculated using supplemental sun beta angle corrections (with a magnitude of about 0.5%) for the MODIS Aqua solar diffuser measurements in the ocean color bands. The initial corrections were derived using a three-year time series of solar diffuser measurements. This paper presents an update to these corrections for Aqua using a six-year time series, and describes the effect of these new corrections on the resulting calibration coefficients. The corrections are also described for the MODIS on Terra. The magnitude of the corrections for Terra is significantly less than for Aqua, and the sign of the response to the beta angle in Terra is opposite to that of Aqua.

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Gerhard Meister, Junqiang Sun, Robert E. Eplee Jr., Frederick S. Patt, Xiaoxiong Xiong, and Charles R. McClain "Sun beta angle residuals in solar diffuser measurements of the MODIS ocean bands", Proc. SPIE 7081, Earth Observing Systems XIII, 70810D (20 August 2008); https://doi.org/10.1117/12.796291

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