Solar Flux Measurements from the Pioneer Venus Sounder Probe

The LSFR instrument and the reduction and analysis of the LSFR data are
described in some detail in Measurements of the Flux of Sunlight in the
Atmosphere of Venus by M. G. Tomasko, L. R. Doose, Peter H. Smith, and
A. P. Odell, J.G.R., volume 85, 1980.

The upward, downward, and net fluxes measured by the LSFR are presented in
UADS file LSFRDAT.  The table in that file contains 12 columns, as follows:

TIME -    The ground receipt time corresponding to when the data sample
          was taken.
PRESS -   The atmospheric pressure in earth atmospheres when the data
          sample was taken.  The pressure and altitude are derived from
          interpolation in the LAS experiment results distributed on
          April 11, 1979.  CAUTION - this may not be the most recent
          time - pressure - altitude table.
ALT -     The altitude of the sample in kilometers, again obtained by
          interpolation in the LAS table of April 11, 1979.

The remaining nine columns are fluxes in watts per square meter.  Some data
are missing at 19:53:57.49 because of a gap in the telemetry.

VIS UP, DOWN, and NET - The upward going, downward going, and net
          (downward going minus upward going) flux in the LSFR visible
          channel.  This channel extends from approximately 0.40 to 0.96
          microns.  Note that the width of the spectral profile of this
          channel changes somewhat during the descent due to temperature
          effects ( see Tomasko et al., 1980).

COMBINED UP, DOWN, and NET - The upward going, downward going, and net
          fluxes for the LSFR combined channel.  The combined channel is
          a synthesis of both the visible and infrared channels into a
          single broad band.  Its bandpass extends from approximately
          0.41 to 1.78 microns, but it too changes slightly during the
          descent (see Tomasko et al., 1980).  After 19:10:46 the signals
          in the infrared portion of the combined channel were too small
          to measure.  Below about 50 kilometers altitude the combined
          channel fluxes must be viewed with caution.

NB UP, DOWN, and NET - The upward going, downward going, and net fluxes
          for the LSFR narrow-band channel.  This channel extends from
          approximately 0.59 to 0.67 microns.  The upward (and therefore
          also the net) fluxes are not given in the lowest kilometer due
          to an instrumental problem associated with the presence of water
          vapor within the probe )see Tomasko et al., 1980).

Note: An empty data field means that value was blank in the original source
      file.