DOI: 10.25810/22v9-9s08
title: SORCE-SIM TSIS1-SIM Irradiance Calibration Ratio (STICR) V2.0

description: TSIS1-SIM Recalibration of the SORCE-SIM Absolute Irradiance Scale: V02 

This is version 2.0 (V02.0) of the SORCE-SIM to TSIS-SIM Irradiance Calibration Ratio (STICR). This data product uses the temporal overlap of the Solar Radiation and Climate Experiment (SORCE) and the Total and Spectral Solar Irradiance Sensor (TSIS-1) Spectral Irradiance Monitor (SIM) instruments to create an alternate SORCE-SIM irradiance calibration.

The STICR is the mean TSIS-SIM/SORCE-SIM irradiance ratio during the temporal overlap between the two missions (on the L3 SORCE-SIM wavelength scale). The STICR, SORCE-SIM, and TSIS1-SIM mean spectra, plus all ancillary data needed to understand how this ratio was determined are contained in this data product. STICR (V02) is used to create V02 of the SORCE-SIM TSIS-1 Adjusted Values (TAV) irradiance data product (https://doi.org/10.5067/8E8EG9HHVDZS).

In simple terms:
SORCE-SIM V27 (irradiance) * STICR V02 = SORCE-SIM TAV V02 (irradiance).

STICR and TAV V02 use TSIS-SIM V06 and SORCE-SIM V27 publicly available data releases. The STICR data products are housed here, at CU Scholar — a collaborative service of the University of Colorado Libraries and are available in ASCII and IDL SAVfile format at https://doi.org/10.25810/22v9-9s08.

The TAV V02 data product appears in ASCII format in two locations:

LASP SORCE website: http://lasp.colorado.edu/home/sorce/data/, and 
NASA DAAC: https://disc.gsfc.nasa.gov/datasets/SOR3SIMD_TAV_002/summary/.
 
An IDL file reader (http://lasp.colorado.edu/data/sorce/file_readers/read_lasp_ascii_file.pro) is available which will read the TAV or attached STICR ASCII file (sorce_sim_L3_tav_cal_v02.0.txt) and return an array of structures whose field names and types are defined in the attached release notes. The STICR IDL SAVfile available on this website (sorce_sim_L3_tav_cal_v02.0.sav) contains all the information in the ASCII file, plus additional information such as the specific days during the SORCE-SIM and TSIS1-SIM temporal overlap which were used in the determination of the STICR.

The TAV V02 data product appears in NetCDF format in two locations:

LASP SORCE website:  http://lasp.colorado.edu/home/sorce/data/, and
LASP LISIRD website: http://lasp.colorado.edu/lisird/data/sorce_sim_tav_l3b/
 
The TAV V02.0 data product is also available as an IDL SAVfile from the LASP website: https://lasp.colorado.edu/home/sorce/data/.

STICR V01.1 differed from V1.0 in that the TSIS ground calibration error estimate was been removed from the TSIS_UNC column and placed into the TSIS_CAL_ERR column.

STICR V02.0 differs from V1.1 in that 

all irradiances and ratios are now double-precision values, 
the version of TSIS1-SIM used was updated from V05 to V06, 
the TAVR_VER (TAV_RATIO version number) column was changed from an I3 to an F5.1 to allow subversions, and 
the IDL SAVfile STICR.AUTOCORR structure now includes an array named NUSED_PER_ABIN to document the number of spectra used for each autocorrelation bin for each wavelength.
 
Complete details on the STICR creation and attached data sets are contained in the included release notes.