Composite Solar Spectral Irradiance
Zipped text data file (17 Mb) composite_ssi.zip
IDL function to read (unzipped) text file read_lasp_ascii_file.pro
IDL save file of the SSI data (17 Mb) composite_ssi.sav
The data provided here are daily average solar spectra over the wavelength range 120-400 nm in 1 nm bins, covering the time period 1978-Nov-08 to 2005-Aug-01. This data set was created by merging the public irradiance data products from six different satellite instruments: SME, Nimbus-7 SBUV, NOAA-9 SBUV/2, NOAA-11 SBUV/2, UARS SUSIM, and UARS SOLSTICE. A detailed discussion of this process can be found in the PDF file comp_uv_irrad.pdf or at the JGR. It is recommended that users who are specifically interested in solar Lyman alpha irradiance data should use the Composite Lyman-Alpha data set, rather than using the contents of the 121.5 nm bin in the composite spectral irradiance data set.
This work has been done by, and these data are provided by:
Science Systems and Applications, Inc. (SSAI)
10210 Greenbelt Road, Suite 600
Lanham, MD 20706 USA
E-mail: Matthew Deland
Each record of this data set has the following fields: Julian Day Number, wavelength (nm), source code (see next paragraph), irradiance (mW/m^2/nm), absolute uncertainty (pct) and long-term uncertainty (pct). The long-term (or 'time-dependent') uncertainty is useful for comparing two points separated by an arbitrary length of time, for example, to compare the relative magnitude of the solar-cycle mimima at a particular wavelength.
Source codes: The third field in each data record contains the source code. The 10's digit indicates the instrument: 10 (Nimbus-7), 20 (SME), 30 (NOAA-9), 40 (NOAA-11), 50 (UARS-SUSIM), 60 (UARS-SOLSTICE), 90 (Proxy). The 1's digit indicates the data type: 0 (Raw), 1 (Interpolated), 2 (Manipulated), 6 (Mg-II + contrast; regression), 7 (Mg-II + contrast; observed), 8 (Mg-II + scale; regression), 9 (Mg-II + scale; observed). See the paper referenced above for further details.