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[McIDAS #CLT-967906]: update and some questions



Hi Ioan,

re:
> long time no hear...

Yes indeed!

re:
> how are you doing....? have you been on holiday? We had a weird summer in
> Europe this year,

I'm doing well, thanks.  I did have a holiday in England in July, but I've
been back for almost a month now.

re:
> the June and July were quite cold.....  but now the temps are as they
> should.

It has been very warm here, and WAY too dry!

re:
> As for me no real  holiday this year ...I was working:)))

I know the feeling :-(

re:
> I have managed to port pyadde and pyarea to python 3 (async) and built an
> integrated (multisource) data downloader which should ensure we do not
> miss any data in case some sources do not work.

This sounds very interesting and useful!

re:
> I'll send you the updated libs (pyadde pyarea) once I package them.

Thanks.

re:
> I want to discuss shortly two things:
> 
> A. GOES16
> I believe I have already asked you this question but I am going to do it
> again in case you got some update on the matter in the meantime.
> 
> Right now we have 3 sources of GOES16 data
> 
> 1. real time 
> https://www.googleapis.com/storage/v1/b/gcp-public-data-goes-16/o NetCDF
> 2. lead.unidata.ucar.edu McIDAS AREA
> 3. CLASS NetCDF

Excellent, I always like redundancy.

You can add to your list:

4. atm.ucar.edu - McIDAS AREA (via ADDE)
5. thredds-test.unidata.ucar.edu netCDF (via the TDS)

Coming up sometime reasonably soon will be:

6. adde.ucar.edu - McIDAS AREA (via ADDE)
7. thredds.ucar.edu - netCDF (via the TDS)

re:
> I was wondering if you got any updates/news from SSEC on the ABI McIDASX
> server because some calibration parameters are still missing from the AREA
> files.

I don't recall you asking this previously, so please forgive the questions:

- which calibration parameters are missing from the calibration block in a
  McIDAS AREA file?

I just looked at the SSEC-written server code for the GRB-delivered ABI imagery,
and I think that it reads and stores all of the calibration information that
is available in the netCDF-4 files that are created by the CSPP GEO software
that we are running on our GOES-16 downlink.

Here are what I deem to be calibration-related values in the GRB netCDF-4 files
(please correct me when I am wrong/missing something!):

        short Rad(y, x) ;
                Rad:_FillValue = 1023s ;
                Rad:long_name = "ABI L1b Radiances" ;
                Rad:standard_name = "toa_outgoing_radiance_per_unit_wavelength" 
;
                Rad:_Unsigned = "true" ;
                Rad:sensor_band_bit_depth = 10b ;
                Rad:valid_range = 0s, 1022s ;
                Rad:scale_factor = 0.8121064f ;
                Rad:add_offset = -25.93665f ;
                Rad:units = "W m-2 sr-1 um-1" ;
                Rad:resolution = "y: 0.000028 rad x: 0.000028 rad" ;
                Rad:coordinates = "band_id band_wavelength t y x" ;
                Rad:grid_mapping = "goes_imager_projection" ;
                Rad:cell_methods = "t: point area: point" ;
                Rad:ancillary_variables = "DQF" ;

The operative calibration values from this list should be: scale_factor and 
add_offset.

        float band_wavelength(band) ;
                band_wavelength:long_name = "ABI band central wavelength" ;
                band_wavelength:standard_name = 
"sensor_band_central_radiation_wavelength" ;
                band_wavelength:units = "um" ;

The operative calibration value here is the band_wavelength itself.

        float kappa0 ;
                kappa0:_FillValue = -999.f ;
                kappa0:long_name = "Inverse of the incoming top of atmosphere 
radiance at current earth-sun distance (PI d2 esun-1)-1, where d is the ratio 
of instantaneous Earth-Sun distance divided by the mean Earth-Sun distance, 
esun is the bandpass-weighted solar irradiance and PI is a standard constant 
used to convert ABI L1b radiance to reflectance" ;
                kappa0:units = "(W m-2 um-1)-1" ;
                kappa0:coordinates = "band_id band_wavelength t" ;
                kappa0:cell_methods = "t: mean" ;
        float planck_fk1 ;
                planck_fk1:_FillValue = -999.f ;
                planck_fk1:long_name = "wavenumber-dependent coefficient (2 h 
c2/ nu3) used in the ABI emissive band monochromatic brightness temperature 
computation, where nu =central wavenumber and h and c are standard constants" ;
                planck_fk1:units = "W m-1" ;
                planck_fk1:coordinates = "band_id band_wavelength" ;
        float planck_fk2 ;
                planck_fk2:_FillValue = -999.f ;
                planck_fk2:long_name = "wavenumber-dependent coefficient (h c 
nu/b) used in the ABI emissive band monochromatic brightness temperature 
computation, where nu = central wavenumber and h, c, and b are standard 
constants" ;
                planck_fk2:units = "K" ;
                planck_fk2:coordinates = "band_id band_wavelength" ;
        float planck_bc1 ;
                planck_bc1:_FillValue = -999.f ;
                planck_bc1:long_name = "spectral bandpass correction offset for 
brightness temperature (B(nu) - bc_1)/bc_2 where B()=planck_function() and 
nu=wavenumber" ;
                planck_bc1:units = "K" ;
                planck_bc1:coordinates = "band_id band_wavelength" ;
        float planck_bc2 ;
                planck_bc2:_FillValue = -999.f ;
                planck_bc2:long_name = "spectral bandpass correction scale 
factor for brightness temperature (B(nu) - bc_1)/bc_2 where 
B()=planck_function() and nu=wavenumber" ;
                planck_bc2:units = "1" ;
                planck_bc2:coordinates = "band_id band_wavelength" ;

All of these values are needed for calibration.

The McIDAS-X server code for GRB ABI imagery contains:

      memcpy( (void *)&cal_block[0], (void *)"ABIN",4); 
      cal_block[j]    = image_band;
      cal_block[j+1]  = (int)(WaveLength[image_band-1] *10000000.0);
      cal_block[j+2]  = (int)(VAR_scale[image_band-1]  *10000000.0); 
      cal_block[j+3]  = (int)(VAR_offset[image_band-1] *10000000.0);
      cal_block[j+4]  = 0;
      cal_block[j+5]  = 0;
      cal_block[j+6]  = 0;
      cal_block[j+7]  = 0;
      cal_block[j+8]  = 0;
      cal_block[j+9]  = 0; 
      cal_block[j+10] = 0;
      cal_block[j+11] = (int)(kappa[image_band-1]      *10000000.0);
      cal_block[j+12] = 0;
      cal_block[j+13] = (int)(planckFK1[image_band-1]  *10000.0);
      cal_block[j+14] = (int)(planckFK2[image_band-1]  *10000.0);
      cal_block[j+15] = (int)(planckBC1[image_band-1]  *10000000.0);
      cal_block[j+16] = (int)(planckBC2[image_band-1]  *10000000.0);
      cal_block[j+17] = VAR_FillValue[image_band-1];

The association between the values I listed from the netCDF-4 files
are:

netCDF-4          AREA calibration block
----------------+-----------------------
band_wavelength  Wavelength
scale_factor     VAR_scale
add_offset       VAR_offset
kappa0           kappa
planck_fk1       planckFK1
planck_fk2       planckFK2
planck_bc1       planckBC1
planck_bc2       planckBC2

re:
> I have ways to deal with it but It would be so nice if the AREA
> files that come from lead would be one to one  with the NetCDF files.

Which calibration value(s) are missing?

re:
> B: the rebuild of GOES archives using pygvar
> 
> I have made some nice progress with this task. However my boss, is not 100%
> happy because the GOES image are of course a little wobbly (+- 1 px) mostly
> the VIS channel.

I assume that you mean the GOES GVAR images.  I see that the animated GIFs
that you attached were all from GOES-8...

re:
> I am attaching 3 files so you can have a look.
> My question is:...do you know anybody /somebody who tried to correct these
> kind of issues with GOES satellites

I know that a LOT of work was done to correct the inter-band registration
for IR channels for GOES GVAR satellites.  There are more than one published
papers on what the problem was and how it can be corrected.

I feel certain that there has been a LOT of work done on correcting the
registration for older GOES satellites (e.g., GOES-8), but I can't give
you any references, sorry.

re:
> pygvar does a good enough job in my opinion but that one pixel gives my
> boss trouble.:))).

I have observed registration problems with GOES GVAR AND GRB images.  The
only good news is that I see far fewer in the GRB images than I saw in
GVAR images.

re:
> All the best

You too!

Cheers,

Tom
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Ticket Details
===================
Ticket ID: CLT-967906
Department: Support McIDAS
Priority: Normal
Status: Closed
===================
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