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

Hi Ioan,

re:
> Thanks for correcting me here.

No worries.

re:
> I reviewed the
> https://www.goes-r.gov/products/ATBDs/baseline/Imagery_v2.0_no_color.pdf
> and, the  kappa can be used for the same purpose.

The kappa value can be used to calculate albedo from radiances
(albedo = kappa * radiance)for the VIS channels.

re:
> I might be asking too much but could you provide me with some hints on how
> does McIDAS X do the calibration ???.

My day today was consumed by trying to find a bug in a script that files
GOES-16 L2 products using information it gets by cracking (parsing 'ncdump -h')
the netCDF4 files that contain the product.  I think the problem is a bug in how
BASH does regular expression matching in strings...

re:
> I use the scale factor and offset to create radiances 

A quick look at the McIDAS calibration module shows that it does also.

re:
> and the  esun and
> earth_sun_distance_anomaly_in_AU to compute reflectance.

The McIDAS calibration module does not calculate reflectance.  The calibrated
values (from IMGPROBE) for pixels from VIS images (bands 1-6) are:

RAW, RAD, ALB, BRIT

How are you using esun and earth_sun_distance_anomaly_in_AU to calculate
reflectance?

re:
> I am now unsure if I do it correctly. According to my understanding (from
> the above doc) if I multiply radiances with kappa I get reflectances.

McIDAS is calling that product albedo (appropriately scaled to 0 - 100%).

re:
> Perhaps McIDAS X converts scaled radiances or counts to reflectance
> directly.

McIDAS converts raw values to radiances using the scale and offset
and then radiance to albedo for VIS channels and equation 3-5
to convert radiances to temperatures.

re:
> All the best

Does the above help at all?

Cheers,

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