Introducing the TSIS-1 SIM MgII Index

Funded by the Solar Irradiance Science Team's (SIST) CATNIP project, we present a new MgII Index derived from TSIS-1 SIM Solar Spectral Irradiance (SSI) measurements. The TSIS-1 SIM MgII index is produced not only on the standard L3 12-hour and 24-hour cadences, but also using the actual exposure times. Using the actual exposure times allows us to directly compare with other data products, such as Bremen, more precisely, as the MgII Index is known to vary considerably on shorter than daily timescales. Other MgII Indicies, such as GOES-R EUVS-C, are reported at much higher cadence (3 seconds), spectral resolution (0.0022 mm vs 0.16 nm for TSIS-1), and temporal completeness (coverage) than is possible with TSIS-1 SIM. However TSIS-1 SIM is very well calibrated, is traceable to NIST standards, and can be used to assist the calibration of other indices. Here we present the TSIS-1 SIM MgII index and demonstrate how it can be used to verify the degradation corrections that are being developed for GOES-R EUVS-C, and other instruments.