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Laboratory for Atmospheric and Space Physics

Level 2 XPS

SEE Level 2 XPS Solar Irradiance Data

Download multiple days from the TIMED MDC

XPS 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

XPS Data Directory– download any data file

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

Routine Time Series Plots


Detailed Level 2 XPS Description

README_XPS_L2_011.TXT – information for using XPS_L2 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 2 data is time averaged over the entire day, 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


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_L2_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.


SEE Level 2 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 2 data.

SEE XPS Solar Irradiance Data Format

Each data file contains an array of structures with 9 elements

XPS_DATA        STRUCT    = ->  Array[9]

Each XPS_DATA structure has the following form:

** Structure <377448>, 14 tags, length=68, data length=64, refs=1:
   DATE            LONG           2002022
   CHANNEL         INT              1
   WAVE            FLOAT     Array[2]
   FLUX_MEDIAN     FLOAT       0.000875983
   DIFF_MA         FLOAT      -4.73618e-06
   ERR_TOT         FLOAT          0.163672
   ERR_MEAS        FLOAT         0.0123417
   STDEV_MEAS      FLOAT         0.0218227
   COR_1AU         FLOAT           1.03242
   CURRENT         FLOAT          0.459073
   NUMPT           INT              5
   COR_DEGRADE     FLOAT           1.00000
   DEGRADE_MODEL   LONG                 0
   COR_ATMOS       STRUCT    ->  Array[1]

Nested structure COR_ATMOS
** Structure <27a048>, 3 tags, length=12, data length=12, refs=2:

AVG FLOAT 0.999966

MIN FLOAT 0.999965

MAX FLOAT 0.999966

NetCDF file attributes for day 2002022

GLOBAL:

    Title = SEE Level 2 XPS Data Product - calibrated XPS data averaged over a
      day

    Source = SEE POC at LASP / CU

    Mission = TIMED

    Data_product_type = SEE XPS Level 2

    Data_product_version = 011

    Data_product_revision = 01

    Product_format_version = 010

    Software_version = 11.01

    Software_name = write_netCDF.pro called from xps_level2_main.pro

    Calibration_version = 09.01

    Description = Calibrated SEE XPS science data averaged over a day $ 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/level2_xps/xps_L2_2002022_011_01.ncdf

    Date_generated = Tue Oct  4 16:36:43 2011

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

COR_DEGRADE:

    Units = Fractional

    Description = Instrument degradation correction factor

DEGRADE_MODEL:

    Units = None

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

COR_ATMOS.AVG:

    Units = Fractional

    Description = Average of atmospheric correction factors

COR_ATMOS.MIN:

    Units = Fractional

    Description = Minimum of atmospheric correction factors

COR_ATMOS.MAX:

    Units = Fractional

    Description = Maximum of atmospheric correction factors