SEE Level 2A XPS Solar Irradiance Data
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Detailed Level 2A XPS Description
README_XPS_L2A_010.TXT - information for using XPS_L2A data
The 12 X-Ray Photometers (XP) aboard SEE perform full-disk irradiance measurements of the Sun for about 3 minutes every orbit (97 minutes) which usually gives 14-15 measurements per day. 8 of the XPs produce XUV signals (more info on XP coatings) and one other XP provides a hydrogen Lyman-alpha measurement (121.5 nm).
The XPS Level 2A data is time averaged over each measurement, after being 1-AU corrected and removing flares. The 1-AU correction is provided.
| Channel | Coating | Low Wavelength (nm) | High Wavelength (nm) |
|---|
| 1 | Ti/C-14 | 0.10 | 7.00 |
| 2 | Ti/C-10 | 0.10 | 7.00 |
| 3 | Al/Sc/C-24 | 17.00 | 23.00 |
| 5 | Ti/Pd-17 | 0.10 | 10.00 |
| 6 | Ti/Zr/Au-04 | 0.10 | 10.00 |
| 7 | Al/Nb/C-03 | 17.00 | 21.00 |
| 9 | Al/Mn-06 | 0.10 | 7.00 |
| 10 | Cr/Al-07 | 0.10 | 7.00 |
| 11 | Ly-alpha | 121.00 | 122.00 |
After day 205 of 2002 only the green highlighted channels ( 1, 5, & 10) continue to provide XUV signal due to a filter wheel anomaly.
XPS Sensitivity Data from the Bessy calibration
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Reading the Data with IDL
With read_netcdf.pro individual data files may be read using an IDL command such as:
read_netcdf,'see__xps_L2A_2002022_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". Each of the 9 coated diodes used to produce the X-Ray irradiances have a band pass range in the wave array tag.
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SEE Level 2A XPS 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
- plotxps_ts.pro - IDL procedure for plotting a time series of XPS Level 2A data.
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SEE Level 2A XPS Solar Irradiance Data Format
Each data file contains an array of structures with 53 elements
L2A_XPS_DATA STRUCT = -> Array[53]
Each L2A_XPS_DATA structure has the following form:
** Structure <35b928>, 16 tags, length=64, data length=59, refs=1:
DATE LONG 2002022
CHANNEL INT 1
WAVE FLOAT Array[2]
FLUX_MEDIAN FLOAT 0.000863028
DIFF_MA FLOAT 0.00000
ERR_TOT FLOAT 0.163683
ERR_MEAS FLOAT 0.0124845
STDEV_MEAS FLOAT 0.0124845
COR_1AU FLOAT 1.03233
CURRENT FLOAT 0.452283
NUMPT INT 1
QUALITY_FLAGS INT 1
ODC_ID BYTE 4
START_TIME FLOAT 18585.1
STOP_TIME FLOAT 18688.0
FLARE FLOAT 0.985123
NetCDF file attributes for day 2002022
GLOBAL:
Title = SEE Level 2A XPS Data Product - calibrated XPS data averaged over
each observation
Source = SEE POC at LASP / CU
Mission = TIMED
Data_product_type = SEE XPS Level 2A
Data_product_version = 010
Data_product_revision = 01
Product_format_version = 009
Software_version = 10.01
Software_name = write_netCDF.pro called from xps_level2_main.pro
Calibration_version = 08.01
Description = Calibrated SEE XPS science data averaged over an observation
$ at instrument resolution with degradation, atmospheric, and 1AU corrections
History = 10/8/02 DLW Added product_format_version $ 2/17/03 DLW Added
diff_ma.
Filename =
/titus/timed/testing/data/science_dp/level2a_xps/xps_L2A_2002022_010_01.ncdf
Date_generated = Mon Dec 17 17:28:18 2007
DATE:
Units = YYYY-DOY
Description = Date of observation
CHANNEL:
Units = none
Description = Channel index of the 12 XUV Photometers (1-12)
WAVE:
Units = nm
Description = Bandpass wavelength range
FLUX_MEDIAN:
Units = W / m^2
Description = Solar irradiance - median for the day
DIFF_MA:
Units = W / m^2
Description = Difference of median and weighted average solar irradiance over
the day
ERR_TOT:
Units = Fractional
Description = Accuracy of solar irradiance averaged over the day
ERR_MEAS:
Units = Fractional
Description = Measurement precision averaged over the day
STDEV_MEAS:
Units = Fractional
Description = Standard deviation of median for good measurements
COR_1AU:
Units = 1 / (AU^2)
Description = AU correction factor for date
CURRENT:
Units = nanoAmps
Description = Median of Total-Dark-Visible currents from level 1 with FOV
and 1-AU corrections applied
NUMPT:
Units = none
Description = Number of measurements used in daily average
QUALITY_FLAGS:
Units = none
Description = 0 means XPS measures flux greater than 3-sigma above the GOES
XRS long channel correlation, 1 means the XPS is within 3-sigma of the expected
value, 2 is indeterminate due to a lack of available GOES long channel correlation
data
ODC_ID:
Units = none
Description = Memory address of command, valid from 1-254
START_TIME:
Units = Seconds
Description = UT time in seconds of day for start integration used in
observation
STOP_TIME:
Units = Seconds
Description = UT time in seconds of day for the end integration used in
observation
FLARE:
Units = none
Description = Ratio of observation flux_median to daily flux_median
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