XRT irradiance study --- returns!

(by Aki Takeda, 5, February 2019, resumed in response to the inquiry from Chris Moore at SAO.)
added 2008-2015 Ti_poly/Al_mesh irradiance plots (1-Mar-2019).

Our method to derive solar soft X-ray irradiance

IMPORTANT NOTE: To derive irradiance from XRT signals after May-2012(when the stray light started to appear), two types of corrections are required:

(1) Subtraction of stray light image from each X-ray images.
(2) Modify XRT response functions so that it reflects the appearance of the stray light.

This study only handles the correction (1), because we don't have the confident method yet for the correction (2).

More detailed procedure --- note for myself.

  1. [find_amap_pairs.pro]
    Find Al_mesh and Al_poly image pairs taken within 5 minutes for each month.
    Eliminate pairs with bad images (missing frames, SAA, cosmic rays, saturations, etc.).
    Save file names.
  2. [get_disksig_amap.pro]
    Read monthly pairs of Al_mesh & Al_poly images.
    Subtract stray light images from both filter images
    (cf: stray light images for the phase 2, Al_mesh and Al_poly).
    Mask outside 1.10 R_sol and get total intensities(signals).
    Save indexes and signals for each filter.
  3. [sig2teemirrad.pro]
    From the pair of Al_mesh & Al_poly sinals, calculate filter-ratio Te and EM.
    Calculate solar spectrum of the isothermal plasma (with Te, EM=10e44cm^-3) with CHIANTI for the wavelength range of 0.05 to 300A, assuming elemental abundances ('corona' or 'hybrid').
    Calculate total spectral intensities within a specified wavelength range and adjust geometrical factor and observed EM to get the irradiance at 1 AU.
    -- Contents Summary of Generic File: /disk/yla/takeda/xrt_irradiance/teemirrad_v4_hybrid_201606.genx--
    .....  Data Section .....
    ** Structure MS_290034151011, 9 tags, length=506224, data length=502396:
       INDEX_AM        STRUCT    -> MS_290034151010 Array[58]
       TE              DOUBLE    Array[58]
       EM              DOUBLE    Array[58]
       IRRAD1_8        DOUBLE    Array[58]
       IRRAD1_10       DOUBLE    Array[58]
       IRRAD1_12       DOUBLE    Array[58]
       IRRAD04_20      DOUBLE    Array[58]
       IRRAD5_60       DOUBLE    Array[58]
       IRRAD4_200      DOUBLE    Array[58]
    -----------------------------------------------------------
    
  4. [connect_monthly_irrad.pro]
    Connect monthly files to make a single time series for further processing.

XRT Synoptic Composite Images statistics.

SCIA statistics, 1-Nov-2008 through 31-Jan-2019

XRT response functions and filter-ratios.

Al_mesh Ti_poly Al_poly

Al_poly/Al_mesh Ti_poly/Al_mesh

The calcualtion of model solar spectra was done with CHIANTI atomic DB & SW ver. 8.0.7. The elemental abundance files used in the calculation are as follows:

Ionization equilbrium functions : chianti.ioneq was assumed for all cases.

XRT irradiance in 6 wavelength ranges.

Link to the data directory (XRT_outgoing).

Year1-8A1-10A1-12A0.4-20A 5-60A4-200A
2008 TP_AM TP_AM TP_AM TP_AM TP_AM TP_AM
2009 TP_AM TP_AM TP_AM TP_AM TP_AM TP_AM
2010 TP_AM TP_AM TP_AM TP_AM TP_AM TP_AM
2011 TP_AM TP_AM TP_AM TP_AM TP_AM TP_AM
2012 TP_AM TP_AM TP_AM TP_AM TP_AM TP_AM
2013 TP_AM TP_AM TP_AM TP_AM TP_AM TP_AM
2014 TP_AM
AP_AM
TP_AM
AP_AM
TP_AM
AP_AM
TP_AM
AP_AM
TP_AM
AP_AM
TP_AM
AP_AM
2015 TP_AM
AP_AM
TP_AM
AP_AM
TP_AM
AP_AM
TP_AM
AP_AM
TP_AM
AP_AM
TP_AM
AP_AM
2016 AP_AM AP_AM AP_AM AP_AM AP_AM AP_AM
2017 AP_AM AP_AM AP_AM AP_AM AP_AM AP_AM
2018 AP_AM AP_AM AP_AM AP_AM AP_AM AP_AM
2019 AP_AM AP_AM AP_AM AP_AM AP_AM AP_AM


GOES/XRS (1-8A) plot for 2016.6-2017.5

Solar X-ray irradiance measurements (by C. Moore at SAO).