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Level 2 EGS

SEE Level 2 EGS Solar Irradiance Data

Download multiple days from the TIMED MDC

EGS 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

EGS Data Directory– download any data file

EGS L2 Merged NetCDF file (single file) of the daily EGS L2 data products

Routine Time Series Plots


Detailed Level 2 EGS Description

README_EGS_L2_011.TXT – information for using EGS_L2 data

The EUV Grating Spectrograph (EGS) aboard SEE performs measurements of the Sun for about 3 minutes every orbit (97 minutes) which usually gives 14-15 measurements per day. The Level 2 data is time averaged over the entire day, after being 1-AU corrected and removing flares. The 1-AU correction is provided.


Reading the Data with IDL

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

read_netcdf,'see__egs_L2_2002044_005_01.ncdf',d,att

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


SEE Level 2 EGS Software

  • TIMED-SEE NetCDF README – Described IDL source code and gives examples using read_netcdf.pro and write_netcdf.pro
  • read_netcdf.pro – IDL procedure for reading NetCDF files as a structure
  • write_netcdf.pro – IDL procedure for writing a data structure (or array of structures) to a NetCDF file
  • plotegs_ts.pro – IDL procedure for plotting a time series of EGS Level 2 data.
  • plotegs_sp.pro – IDL procedure for plotting a daily averaged spectrum from one EGS Level 2 data file.

SEE Level 2 EGS Solar Irradiance Data Format

Each data file contains a structure with 1 elements

EGS_DATA        STRUCT    = ->  Array[1]

The EGS_DATA structure has the following form:

** Structure <281ec8>, 14 tags, length=98032, data length=98032, refs=1:
   DATE            LONG           2002039
   WAVE            FLOAT     Array[1690]
   FLUX_MEDIAN     FLOAT     Array[1690]
   DIFF_MA         FLOAT     Array[1690]
   ERR_TOT         FLOAT     Array[1690]
   ERR_MEAS        FLOAT     Array[1690]
   STDEV_MEAS      FLOAT     Array[1690]
   NUMPT           INT       Array[1690]
   COR_1AU         FLOAT           1.02768
   COR_OS_MED      FLOAT     Array[1690]
   COR_OS_AVG      FLOAT     Array[1690]
   DEGRADE_MODEL   LONG                 0
   COR_ATMOS       STRUCT    ->  Array[1]
   COR_DEGRADE     STRUCT    ->  Array[1]

Nested structure COR_ATMOS
** Structure <27a2d8>, 3 tags, length=20280, data length=20280, refs=2:

AVG FLOAT Array[1690]

MIN FLOAT Array[1690]

MAX FLOAT Array[1690]

Nested structure COR_DEGRADE
** Structure <2f28f8>, 3 tags, length=20280, data length=20280, refs=2:

AVG FLOAT Array[1690]

MIN FLOAT Array[1690]

MAX FLOAT Array[1690]

NetCDF file attributes for day 2002039

GLOBAL:

    Title = SEE Level 2 EGS Data Product - calibrated 0.1nm EGS data averaged
      over a day

    Source = SEE POC at LASP / CU

    Mission = TIMED

    Data_product_type = SEE EGS Level 2

    Data_product_version = 011

    Data_product_revision = 02

    Product_format_version = 010

    Software_version = 11.01

    Software_name = write_netCDF.pro called from egs_level2_main.pro

    Calibration_version = 09.01

    Description = Calibrated SEE EGS science data averaged over a day $ at 0.1
      nm bins with degradation, atmospheric, and 1AU corrections

    History = 10/8/02 Don Woodraska Added product_format_version. $ 1/28/03 Don
      Woodraska Added order sorting corrections. $

    Filename =
      /titus/timed/testing/data/science_dp/level2_egs/egs_L2_2002039_011_02.ncdf

    Date_generated = Tue Sep 11 19:41:02 2012

DATE:

    Units = YYYY-DOY

    Description = Date of observation

WAVE:

    Units = nm

    Description = Array of wavelength intervals, half-Angstrom centers

FLUX_MEDIAN:

    Units = W / m^2 / nm

    Description = Array of median solar irradiances for each wavelength interval.
      This is the spectrum

DIFF_MA:

    Units = W / m^2 / nm

    Description = Array of differences between the median and weighted averaged
      solar irradiances for each wavelength interval

ERR_TOT:

    Units = Fractional

    Description = Accuracy of solar irradiance

ERR_MEAS:

    Units = Fractional

    Description = Measurement precision

STDEV_MEAS:

    Units = Fractional

    Description = Standard deviation of the median

NUMPT:

    Units = NONE

    Description = Array of the Number of points (1-Angstrom-gridded measurements)
      used in determining the daily average for each wavelength interval

COR_1AU:

    Units = 1 / (AU^2)

    Description = AU correction factor for date

COR_OS_MED:

    Units = W/m^2/nm

    Description = Order Sorting correction applied to flux_median

COR_OS_AVG:

    Units = W/m^2/nm

    Description = Order Sorting correction applied to weighted avg irradiance

DEGRADE_MODEL:

    Units = None

    Description = Long value = 1 if degradation function is linearly extrapolated,
      0 if linearly interpolated

COR_ATMOS.AVG:

    Units = Fractional

    Description = Array of Averaged atmospheric correction factors for each
      wavelength interval

COR_ATMOS.MIN:

    Units = Fractional

    Description = Array of Minimum atmospheric correction factors

COR_ATMOS.MAX:

    Units = Fractional

    Description = Array of Maximum atmospheric correction factors

COR_DEGRADE.AVG:

    Units = Fractional

    Description = Array of Average instrument degradation correction factors

COR_DEGRADE.MIN:

    Units = Fractional

    Description = Array of Minimum instrument degradation correction factors

COR_DEGRADE.MAX:

    Units = Fractional

    Description = Array of Maximum instrument degradation correction factors