NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Changes in photochemically significant solar UV spectral irradiance as estimated by the composite Mg II index and scale factorsQuantitative assessment of the impact of solar ultraviolet irradiance variations on stratospheric ozone abundances currently requires the use of proxy indicators. The Mg II core-to-wing index has been developed as an indicator of solar UV activity between 175-400 nm that is independent of most instrument artifacts, and measures solar variability on both rotational and solar cycle time scales. Linear regression fits have been used to merge the individual Mg II index data sets from the Nimbus-7, NOAA-9, and NOAA-11 instruments onto a single reference scale. The change in 27-dayrunning average of the composite Mg II index from solar maximum to solar minimum is approximately 8 percent for solar cycle 21, and approximately 9 percent for solar cycle 22 through January 1992. Scaling factors based on the short-term variations in the Mg II index and solar irradiance data sets have been developed to estimate solar variability at mid-UV and near-UV wavelengths. Near 205 nm, where solar irradiance variations are important for stratospheric photo-chemistry and dynamics, the estimated change in irradiance during solar cycle 22 is approximately 10 percent using the composite Mg II index and scale factors.
Document ID
19950004711
Document Type
Conference Paper
Authors
Deland, Matthew T. (Hughes STX, Inc. Lanham, MD, United States)
Cebula, Richard P. (Hughes STX, Inc. Lanham, MD, United States)
Date Acquired
September 6, 2013
Publication Date
April 1, 1994
Publication Information
Publication: NASA. Goddard Space Flight Center, Ozone in the Troposphere and Stratosphere, Part 2
Subject Category
GEOPHYSICS
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

NameType 19950004711.pdf STI

Related Records

IDRelationTitle19950004531Analytic PrimaryWorkshop on the Analysis of Interplanetary Dust Particles