Monitoring the Calibration of the DSCOVR EPIC Instrument's Visible Channels using MODIS and VIIRS as a Reference
Abstract
The Earth Polychromatic Imaging Camera (EPIC) instrument aboard the Deep Space Climate Observatory (DSCOVR) satellite has a constant unique view of the sunlit disk of the Earth from the Lagrange-1 (L1) point nearly a million miles away from the Earth. Due to EPIC not having any on-board calibration systems, the ten spectral channels of EPIC must be vicariously calibrated while on-orbit. We monitor the EPIC calibration by inter- calibrating with the well-calibrated Aqua-MODIS and SNPP-VIIRS radiometers utilizing ray- matched radiance pairs. The recently released EPIC version 3 L1B data has greatly mitigated the residual navigation errors found in prior versions, thereby decreasing the calibration uncertainty in the aforementioned ray-matching calibration techniques. We have independently developed an EPIC navigation correction, based on simple alignment of the EPIC image to match the features of the MODIS and VIIRS reference image, in order to facilitate the EPIC ray-matching approach. We attempt to improve this approach by using optical flow to track the EPIC image features with the corresponding MODIS and VIIRS images. The DSCOVR satellite went into safe mode on June 27, 2019 due to an anomaly with the satellite's attitude control system, but operations recommenced on March 2, 2020. The EPIC calibration prior and after the safe mode incident will be compared in order to investigate any potential calibration shifts or discontinuities caused by the spacecraft anomaly.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMA149.0009H
- Keywords:
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- 3311 Clouds and aerosols;
- ATMOSPHERIC PROCESSES;
- 3359 Radiative processes;
- ATMOSPHERIC PROCESSES;
- 3360 Remote sensing;
- ATMOSPHERIC PROCESSES;
- 0426 Biosphere/atmosphere interactions;
- BIOGEOSCIENCES