SOHO/VIRGO TSI Version 8.0 source notes

Dataset: VIRGO Total Solar Irradiance (TSI) daily, Version 8.0
Instrument: VIRGO (PMO6-V and DIARAD channels, A+B fused) on SOHO
Platform: SOHO (Solar and Heliospheric Observatory), ESA/NASA cooperative mission

Raw file URL (authoritative HTTPS):
https://soho.nascom.nasa.gov/data/EntireMissionBundles/VIRGO_TSI_daily_V8.txt

Local raw file:
tsi_raw/soho_virgo_v8/raw/VIRGO_TSI_daily_V8.txt

Coverage: 1996-01-18 to 2021-09-26 (daily, ~9170 rows)
PMOD FTP source (blocked on this network):
ftp://ftp.pmodwrc.ch/pub/data/irradiance/virgo/TSI/

Column layout (from header):
  Col 1: UTC time (ISO 8601)
  Col 2: TAI (seconds)
  Col 3: Julian Date
  Col 4: TSI PMO6V-A degradation-corrected [original VIRGO/WRR scale, ~1365 W/m^2]
  Col 5: TSI VIRGO A+B fused [original VIRGO/WRR scale, ~1365 W/m^2]
  Col 6: Uncertainty of fused series
  Col 7: TSI PMO6V-A [new SI-traceable scale, ~1361 W/m^2]
  Col 8: TSI VIRGO A+B fused [new SI-traceable scale, ~1361 W/m^2]  <-- main plotted value

Attribution (required per header):
  Finsterle, W., Montillet, J.P., Schmutz, W. et al. The total solar irradiance during
  the recent solar minimum period measured by SOHO/VIRGO. Sci Rep 11, 7835 (2021).
  https://doi.org/10.1038/s41598-021-87108-y
  Acknowledge: "VIRGO Experiment on the cooperative ESA/NASA Mission SoHO from VIRGO Team
  through PMOD/WRC, Davos, Switzerland"

Scale note:
  Original and new VIRGO scales differ by 0.34% (~4.6 W/m^2 offset). This build script
  plots the NEW (SI-traceable) scale (col 8, ~1361 W/m^2), consistent with modern TIM values.
  Original scale values (col 5, ~1365 W/m^2) are also exported in the CSV.

Downloaded: 2026-06-04 via NASA SOHO archive (HTTPS, bypassing blocked PMOD FTP)