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Laboratory for Atmospheric and Space Physics

SORCE-SIM TAV (TSIS1 Adjusted Values)

The temporal overlap of the Solar Radiation and Climate Experiment (SORCE) and Total and Spectral Solar Irradiance Sensor (TSIS-1) Spectral Irradiance Monitor (SIM) instruments allows us to create an alternate SORCE-SIM irradiance calibration, known as the TSIS Adjusted Values (TAV).

This is TAV version 02 (V02), using the SORCE-SIM V27 and TSIS-SIM V06 data releases. The DOI for V02 of the TSIS-1 Adjusted Values (TAV) data product is

This re-calibration is based solely upon the temporal overlap of TSIS-1 and SORCE, without any additional corrections for instrument degradations. As such, the irradiance values at the end of the SORCE mission are guaranteed to agree with TSIS-1, but this may not be true for earlier in the SORCE mission due to uncorrected SORCE degradation or instrumental issues.

The TAV re-calibration is achieved by multiplying the SORCE-SIM V27 irradiances by V02 of the SORCE-SIM to TSIS-SIM Irradiance Calibration Ratio (STICR), which is contained in a separate data product (

In simple terms, SORCE-SIM (irradiance) * STICR = SORCE-SIM TAV (irradiance).

The TAV data product appears in ASCII format in two locations:

  1. LASP SORCE website (see: and
  2. NASA DAAC (see: The NASA DAAC short-name for the ASCII data product is SOR3SIMD_TAV.

An IDL file reader ( is available which will read the TAV ASCII file and return an array of structures whose field names and types are defined in the release notes.

The TAV V02.0 data product is also available as an IDL SAVE file from the LASP website (

TAV V01.1 differs from V01 in that the irradiancies used, and those reported in the TAV data products, have been changed from the E11.4 to E13.6 format to prevent rounding errors. The new format ensures that rounding errors for both V27 SIM and V01.1 of TAV are less than 0.5 parts per million (PPM). In conjunction with the ASCII format change, the ‘irradiance’ variable type was changed from float (R4) to double-precision (R8) in the IDL SAVE file.

TAV V02.0 differs from V01.1 in that V06 of TSIS1-SIM is used in creating the V02.0 of STICR. All TAV V01 versions used TSIS1-SIM data release V05.

Further details on TAV V02 and SORCE-SIM V27 can be found by locating the release notes on the LASP website at Further details, release notes, and STICR data can be found at is TSIS-1 data and release notes can be obtained from