Level 3A

SEE Level 3A Solar Irradiance Data

Download multiple days from the TIMED MDC

SEE L3A Calendar Access: Useful for finding data for a specific day.

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023

Level 3A Data Directory – download any data file

SEE Level 3A Merged NetCDF file (single file) of the daily SEE Level 3A data products

Level 3A SSI LISIRD – interactive data access and plotting

Level 3A Lines LISIRD – interactive data access and plotting

Level 3A Diodes LISIRD – interactive data access and plotting

Detailed Level 3A Description

README_SEE_L3A_012.TXT – information for using SEE L3A data

SEE Level 3A data files contain each measurements averaged solar irradiance spectrum in 1 nm intervals extracted from the EGS Level 2A and XPS Level 2A data products. Shortward of 27 nm, a solar model is scaled to match the XPS broadband data. SEE Level 3A data files also contain 38 emission lines extracted from EGS Level 2A spectra, and the XPS Level 2A diode irradiances.

For normal operations, SEE observes the Sun for about 3 minutes every orbit (97 minutes), which usually gives 14-15 measurements per day. The SEE Level 3A data are time averaged over each measurement, after applying corrections for atmospheric absorption, degradation, flare removal, and to 1-AU.

Reading the Data with IDL

With read_netcdf.pro individual data files may be read using an IDL command such as:


The data will then reside in the returned structure “d”, with each tag in the structure defined in the attributes array “att”.

SEE Level 3A Software

SEE Level 3A Solar Irradiance Data Format

Each data file contains an array of structures with 8 elements

L3A_DATA        STRUCT    = ->  Array[8]

Each L3A_DATA structure has the following form:

** Structure <27b8d8>, 11 tags, length=4752, data length=4745, refs=1:
   DATE            LONG           2002039
   ODC_ID          BYTE        20
   START_TIME      FLOAT           3292.00
   STOP_TIME       FLOAT           3452.00
   COR_1AU         FLOAT           1.02768
   EGS_FLARE       FLOAT           1.00223
   XPS_FLARE       FLOAT           1.02361
   XPS_TIME        FLOAT           0.00000
   SP              STRUCT    ->  Array[1]
   LINE            STRUCT    ->  Array[1]
   XPS             STRUCT    ->  Array[1]
Nested structure SP
 ** Structure <2fed38>, 4 tags, length=3120, data length=3120, refs=2:
  WAVE FLOAT Array[195]
  FLUX FLOAT Array[195]
  ERR_TOT FLOAT Array[195]
  ERR_MEAS FLOAT Array[195]
Nested structure LINE
 ** Structure <2eaf88>, 6 tags, length=1368, data length=1368, refs=2:
  WAVE FLOAT Array[38]
  FLUX FLOAT Array[38]
  ERR_TOT FLOAT Array[38]
  ERR_MEAS FLOAT Array[38]
  NAME STRING Array[38]
  LOGT FLOAT Array[38]
Nested structure XPS_SF
 ** Structure <277428>, 3 tags, length=12, data length=12, refs=2:
  QS FLOAT 1.00000
  AR FLOAT 0.204324
  FLARE FLOAT 0.00418555
Nested structure XPS
 ** Structure <2fe7d8>, 7 tags, length=228, data length=228, refs=2:
  WAVE_XPS_1 FLOAT Array[9]
  WAVE_XPS_2 FLOAT Array[9]
  FLUX FLOAT Array[9]
  ERR_TOT FLOAT Array[9]
  XPS_SF STRUCT -> Array[1]

NetCDF file attributes for day 2002039


    Title = SEE Level 3A Observation Averaged Data Product - merged XPS and EGS

    Source = SEE POC at LASP / CU

    Mission = TIMED

    Data_product_type = SEE Level 3A

    Data_product_version = 011

    Data_product_revision = 01

    Product_format_version = 010

    Software_version = 11.01

    Software_name = write_netCDF.pro called from see_level3a_main.pro

    Calibration_version = 09.01

    Description = Calibrated SEE EGS and XPS science data averaged over each
      solar observation at 1nm intervals

    History = 9/10/03 Don Woodraska Original creation

    Filename =

    Date_generated = Wed Sep 12 05:01:12 2012


    Units = YYYY-DOY

    Description = Date of observation


    Units = none

    Description = byte for the observation identifier (1-254)


    Units = seconds of UT day

    Description = Observation start times


    Units = seconds of UT day

    Description = Observation stop times


    Units = 1 / (AU^2)

    Description = AU correction factor for date


    Units = Fraction

    Description = mean selected EGS lines ratio to daily median


    Units = Fraction

    Description = XPS diode #1 ratio to daily median


    Units = seconds of UT day

    Description = Time of nearest XPS measurement to the SEE EGS measurement


    Units = nm

    Description = 1nm bins at center of wavelength bin (half-integral)


    Units = W / m^2 / nm

    Description = Merged Solar irradiance for XPS and EGS flux at 1nm bins with
      gaps filled using Woods-Rottman 2002 VUV model. Below 26 nm, flux is result of
      solution of linear equations involving XPS diodes and scaled to the VUV model.
      EGS data is used above 26 nm except 114.5-120.5 and 122.5-128.5 nm where the VUV
      model is scaled to the EGS Lyman-alpha line.


    Units = Fractional

    Description = Accuracy of solar irradiance


    Units = Fractional

    Description = Measurement precision


    Units = nm

    Description = Reference wavelengths for spectral lines


    Units = W / m^2

    Description = Integrated spectral line irradiance


    Units = Fractional

    Description = Accuracy of spectral line irradiance


    Units = Fractional

    Description = Measurement precision of spectral line irradiance


    Units = None

    Description = Text indicating the largest contribution to spectral line


    Units = None

    Description = Logarithm of Temperature for spectral line


    Units = nm

    Description = Lower limit for XPS diode bandpass filter


    Units = nm

    Description = Upper limit for XPS diode bandpass filter


    Units = W / m^2

    Description = Observational median flux for the diode (Level 2)


    Units = Fractional

    Description = Accuracy of XPS level 2 irradiance


    Units = Fractional

    Description = Measured uncertainty in XPS level 2 irradiance


    Units = nanoAmps

    Description = Median of Total-Dark-Visible currents from level 1 with FOV
      and 1-AU corrections


    Units = None

    Description = Scalefactor from XPS Level 4 model for daily Quiet Sun


    Units = Nanometers

    Description = Scalefactor from XPS Level 4 model for daily Active Region


    Units = Fractional

    Description = Scalefactor from XPS Level 4 model for flare component
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