ACSPO EWA Resampling parameters should be set to 40:1 for all instruments.

[kathys]

After looking closely at the Version 2.3 versus 3.0 ACSPO SST images, I think the originals look very good. V3.0 is using 10:1 for MODIS, which results in holes at the edges of the scan, and we have already demonstrated the improved detail in the 40:1 for VIIRS, so I think the original V2.3 values will work best for MODIS, VIIRS and AVHRR.

[kathys]

There is still something different about how these ACSPO images are being created for MODIS when compare with P2G Version 2.3. When I look at the images created with V2.3, the EWA resampling options are set to 40:1 and the values look good and complete to the edge of the scan, but the V3.0 Oct. tarball images still show holes as you approach the edge of scan.

Example images from my Aqua test data set. V2.3 on top, V3.0 bottom

bumi:/data/users/kathys/test_data/acspo/aqua
bumi:/data/users/kathys/test_data/acspo/aqua_v3

[kathys]

I should also say that the other instrument products, AVHRR and VIIRS, look good now.

[djhoese]

I'll take a look. I remember during some of the AWIPS testing for v3.0 that I discovered that AVHRR was showing holes (L1b, not ACSPO) but it showed it in v2.3 too.

[djhoese]

This is very strange. I'm doing initial tests and even in the black and white image (no colormap added) the scaling looks very different even though both logs say they are doing the same scaling. This should be fun...

[djhoese]

Turns out it is an easy fix: pytroll/satpy#2239

Rows per scan weren't being set right in the reader in Satpy (I accidentally broke it) so the EWA resampling was treating the entire swath as one large scan. That is only expected for AVHRR, not VIIRS and MODIS. This can be closed once that Satpy PR is merged.

[kathys]

Very glad it turned out to be something simple.

[djhoese]

Hhhmm the enhancement is still way off. I'm not sure what is going on:

Version 2.3:

Fixed Version 3.0:

[djhoese]

Ah got it! The v2.3 isn't actually able to scale these files properly. It is missing the following rescale section:

[rescale:default_sst4]
data_kind=sea_surface_subskin_temperature
method=linear
min_in=267.317
max_in=309.816

Which was needed because ACSPO changed the standard_name of the product. It was being dynamically scaled which resulted in slightly different limits.

[kathys]

Nicely done Dave.