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.
EGS Data Directory– download any data file
EGS L2 Merged NetCDF file (single file) of the daily EGS L2 data products
EGS Level 2 LISIRD – interactive data access and plotting
Detailed Level 2 EGS Description
README_EGS_L2_012.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:
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
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 FLUX_MEDIAN FLOAT Array DIFF_MA FLOAT Array ERR_TOT FLOAT Array ERR_MEAS FLOAT Array STDEV_MEAS FLOAT Array NUMPT INT Array COR_1AU FLOAT 1.02768 COR_OS_MED FLOAT Array COR_OS_AVG FLOAT Array DEGRADE_MODEL LONG 0 COR_ATMOS STRUCT -> Array COR_DEGRADE STRUCT -> Array
Nested structure COR_ATMOS ** Structure <27a2d8>, 3 tags, length=20280, data length=20280, refs=2: AVG FLOAT Array MIN FLOAT Array MAX FLOAT Array
Nested structure COR_DEGRADE ** Structure <2f28f8>, 3 tags, length=20280, data length=20280, refs=2: AVG FLOAT Array MIN FLOAT Array MAX FLOAT Array
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