Calibration
As discussed in the User's Guide, the EP/TOMS working diffuser is deployed every week to make solar measurements. The EP/TOMS reference diffuser is deployed only every 10 weeks, So the working to reference ratio indicates degradation of the working diffuser, which is critical to the long-term calibration of EP/TOMS. Every time a working diffuser measurement is made, the near real-time calibration of EP/TOMS is extrapolated for another week to permit continuous processing of the data. The following graphics are used to monitor the quality of this calibration system. The upper plot in both graphics pertains to the single 360 nm channel and affects the calibration of the derived reflectivity. The middle plot pertains to the 331 nm / 360 nm ratio, which affects the aerosol index. The bottom plot pertains to the A-triplet of channels, which corresponds to ozone errors.
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| The working diffuser degradation relative to reference (5K) |