GOES-13 EUVS Calibration and Early-Orbit Validation
CPI and NRL physicists provided the first validation of an important new Geostationary Operational Environmental Satellite (GOES) sensor for measuring solar Extreme Ultraviolet (EUV) energy fluxes in five bands. A contract was awarded by NOAA's Space Weather Prediction Center (SWPC) to the Naval Research Laboratory (NRL) in October, 2006 followed by a 12-month effort to develop a calibration algorithm for the EUV Sensor (named EUVS) and conduct a validation of early on-orbit data. CPI physicists working closely with two NRL solar physicists carried out the work that was highly successful and led to encouragement by SWPC personnel to publish the work in spite of the focus being more operational rather than research based. The publication represents seminal research work on the early observations by this important sensor [Evans, et al., Solar Physics, 262, 2010].
Project highlights were:
- Early identification of a serious calibration error in EUVS data provided by SWPC, determination of its source, and the means to correct it (as detailed in a technical report delivered to SWPC).
- Development of a calibration model with verification that it was performing as designed.
- Completion of sensitivity studies addressing variations in cross-disk luminosity, pointing offsets, and changes in spectral shapes.
- Demonstration of successful calibration through comparisons with independent measurements. This was done with four months of continuous EUVS data, all of which may be seen in the 2010 Solar Physics paper.
- Development of algorithm for constructing flare and non-flare irradiance spectra from 2 to 80 nm using EUVS data from four of its five bands.
GOES-13 EUVS validation results for August 2006. Three sources of NASA satellite data are shown in addition to EUVS: TIMED/SEE (Version 10.02), SOHO/SEM, and SORCE/SOLSTICE. Only for Channel B may EUVS data be compared with those from both SEE and SEM. The bottom panel shows the daily variation of the F10.7 solar proxy.