TIMED SEE

SEE Level 2A EGS Solar Irradiance Data

top

Detailed Level 2A EGS Description

README_EGS_L2A_011.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.

top


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_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".

top


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_ts.pro - IDL procedure for plotting a time series of EGS Level 2A data.
  • plotegs_sp.pro - IDL procedure for plotting the spectrum from one EGS Level 2A data file.
top

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 <319cb8>, 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.
top

.
 
      NASA SEE TIMED LASP

Revised: November 2007
+ Questions or comments?