Geostationary Operational Environmental Satellite (GOES) Extreme Ultraviolet Sensor (EUVS)

CPI and NRL physicists provided the first validation of the important new GOES EUV sensor, which provides energy fluxes in five bands. A contract was awarded by NOAA's Space Weather Prediction Center (SWPC) to 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 NRL solar physicists carried out the work, which 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. Project highlights included: early identification of a serious calibration error in EUVS data provided by SWPC, determination of its source, and the means to correct it; 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 (done with four months of continuous EUVS data); and development of an algorithm for constructing flare and non-flare irradiance spectra from 2 to 80 nm using EUVS data from four of its five bands.

 

The 5 December 2006 X9 flare recorded by GOES/EUVS channels A and E, and SORCE/XPS (after Evans et al., Solar Physics, 262, 2010). Inset: GOES-13 SXI image recorded at 10:44 UTC on 5 December 2006 (source: http://sxi.ngdc.noaa.gov/sxi_greatest.html). The bright horizontal band across the image evidences damage to 8 lines of pixels on the CCD.