SEE Level 2A 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 2018 2019 2020 2021 2022 2023
EGS Level 2A Data Directory– download any data file
EGS Level 2A LISIRD – interactive data access and plotting
Detailed Level 2A EGS Description
README_EGS_L2A_012.TXT – information for using EGS_L2A 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 2A data is time averaged over each measurement, 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_L2A_2002044_012_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 2A 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_sp.pro – IDL procedure for plotting the spectrum from one EGS Level 2A data file.
- plotegs_ts.pro – IDL procedure for plotting a time series of EGS Level 2A data.
SEE Level 2A EGS Solar Irradiance Data Format
Each data file contains a structure with 8 elements
L2A_EGS_DATA STRUCT = -> Array[8]
The L2A_EGS_DATA structure has the following form:
** Structure <2e41c8>, 15 tags, length=50728, data length=50722, 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_OS_MED FLOAT Array[1690] COR_1AU FLOAT 1.02768 SLIT BYTE 1 START_TIME FLOAT 3292.00 STOP_TIME FLOAT 3452.00 ODC_ID BYTE 20 FLARE FLOAT 1.00223
NetCDF file attributes for day 2002039
GLOBAL:
Title = SEE Level 2A EGS Observation Averaged Data Product - calibrated 0.1nm
EGS data averaged over ~ 3 minutes
Source = SEE POC at LASP / CU
Mission = TIMED
Data_product_type = SEE EGS Level 2A
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 each solar
observation $ at 0.1 nm bins with degradation, atmospheric, and 1AU corrections
History = 7/03/03 Don Woodraska Original creation
Filename =
/titus/timed/testing/data/science_dp/level2a_egs/egs_L2A_2002039_011_02.ncdf
Date_generated = Tue Sep 11 19:41:02 2012
DATE:
Units = YYYY-DOY
Description = Date of observations
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 observation average for each wavelength interval
COR_1AU:
Units = 1 / (AU^2)
Description = AU correction factor for date
SLIT:
Units = none
Description = 0 is calibration slit, 1 is normal slit
START_TIME:
Units = UT seconds of day
Description = Array of observation start times
STOP_TIME:
Units = UT seconds of day
Description = Array of observation stop times
ODC_ID:
Units = none
Description = Array of observation identifiers (1-254), A value of 0 means
the observation did not produce data used in routine products.
