Waves in MSG image

[Fabio Mingione]

Hi again Pytroll community, 

We're experiencing another issue with the processing of MSG products.

We use the attached .py script to produce the 'MSGwaves.jpg' image through Satpy commands. As you can see, undesired "waves" appear on the top of the image. 

Below you can see an extract of the composite and area defined by us:

-------------------------------------------------------------------------------------

seviri.yaml extract:

palette_ir_ocinca:
compositor: !!python/name:satpy.composites.SingleBandCompositor
prerequisites:
- name: 'IR_108'
standard_name: palette_ir_ocinca

-------------------------------------------------------------------------------------

generic.yaml extract:

palette_ir_ocinca:
standard_name: palette_ir_ocinca
operations:
- name: colorize
method: !!python/name:satpy.enhancements.colorize
kwargs:
palettes:
- {colors: greys, min_value: 210.27, max_value: 336.91}

-------------------------------------------------------------------------------------

areas.yaml exrtact

EUROPAlaea1:
description: EUROPAlaea1
projection:
proj: laea
ellps: WGS84
lat_0: 55.0
lon_0: 10.0
x_0: 1950000.0
y_0: -2100000.0
units: m
shape:
height: 2200
width: 1900
area_extent:
lower_left_xy: [-0.1785495684016496, -4399999.421723187]
upper_right_xy: [3799999.6290370002, 0.1088811312802136]

Do you know what the possible cause might be?

Thanks!

Kind regards,

Fabio

[Panu Lahtinen]

On 9.5.2022 12.38, Fabio Mingione wrote:
> Hi again Pytroll community,
>
> We're experiencing another issue with the processing of MSG products.
>
> We use the attached .py script to produce the 'MSGwaves.jpg' image
> through Satpy commands. As you can see, undesired "waves" appear on the
> top of the image.
>
> Below you can see an extract of the composite and area defined by us:

This is due to the resampler search distance being too small by default
for the high latitudes. Try replacing

local_scene = IR_Eu_Rad.resample(area)

with

local_scene = IR_Eu_Rad.resample(area, radius_of_influence=50e3)


and you should get better results.


P

--
Finnish Meteorological Institute
Erik Palménin aukio 1, P.O.Box 503, FIN-00101 Helsinki, Finland
Room: 4B15a, Phone: +358 50 380 3261

[Fabio Mingione]

Thanks a lot!

This improved the image significantly indeed.