NOAA20 Sea Surface Temperature

[woo...@gmail.com]

Hi

 

I wonder if someone with more extensive python programming knowledge can help me

 

I am trying to process the NOAA20 sea surface temperature from this file distributed

over Eumetcast in SAF-1 on the Basic service

S-OSI_-FRA_-NOAA20_-NARSST_FIELD-202407231200Z.nc

 

I run  python .\process-NorthAtlanticSST.py NA20202407231200

 

I have two problems

 

Firstly I cant seem to get a polar stereographic projection to work properly

Secondly the sea surface temperature wont plot because the  variable is empty and I dont know why - I think it may be something to do with the lat/long

 

Any help would be much appreciated

 

Thanks

 

Graham

[David Hoese]

Hi Graham,

Please provide any error messages and their complete tracebacks (if available) for the two issues you identified. Thanks.

Dave

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[woo...@gmail.com]

Hi Dave

These are the errors I get with the attached script

(pytroll) PS I:\SPStools\GEOscripts> python .\process-NorthAtlanticSST.py NA20202407231000
[[13.592773  13.598633  13.606445  ... 16.370117  16.364258  16.357422 ]
 [13.603516  13.611328  13.6171875 ... 16.381836  16.375977  16.370117 ]
 [13.615234  13.62207   13.628906  ... 16.393555  16.387695  16.381836 ]
 ...
 [43.756836  43.774414  43.791016  ... 51.24121   51.222656  51.20508  ]
 [43.760742  43.77832   43.79492   ... 51.24707   51.228516  51.210938 ]
 [43.76465   43.782227  43.799805  ... 51.251953  51.234375  51.21582  ]]
[[-31.868164 -31.856445 -31.844727 ...  26.786133  26.798828  26.810547]
 [-31.875    -31.863281 -31.851562 ...  26.791992  26.804688  26.817383]
 [-31.881836 -31.870117 -31.859375 ...  26.798828  26.810547  26.824219]
 ...
 [-75.96973  -75.96484  -75.958984 ...  72.89746   72.90527   72.91406 ]
 [-75.99414  -75.98828  -75.98242  ...  72.924805  72.93359   72.94336 ]
 [-76.01758  -76.01172  -76.00586  ...  72.9541    72.96289   72.9707  ]]
0
11942065
9576463
12460018
[]
Traceback (most recent call last):
  File "I:\SPStools\GEOscripts\process-NorthAtlanticSST.py", line 124, in <module>
    img = ax.imshow(data, vmin=vmin, vmax=vmax, origin='upper', extent=img_extent, cmap=cmap)
  File "C:\Users\graha\miniconda3\envs\pytroll\lib\site-packages\cartopy\mpl\geoaxes.py", line 307, in wrapper
    return func(self, *args, **kwargs)
  File "C:\Users\graha\miniconda3\envs\pytroll\lib\site-packages\cartopy\mpl\geoaxes.py", line 1314, in imshow
    img, extent = warp_array(img,
  File "C:\Users\graha\miniconda3\envs\pytroll\lib\site-packages\cartopy\img_transform.py", line 192, in warp_array
    array = regrid(array, source_native_xy[0], source_native_xy[1],
  File "C:\Users\graha\miniconda3\envs\pytroll\lib\site-packages\cartopy\img_transform.py", line 293, in regrid
    temp_array = array.reshape((-1,) + array.shape[2:])
  File "C:\Users\graha\miniconda3\envs\pytroll\lib\site-packages\numpy\ma\core.py", line 4745, in reshape
    result = self._data.reshape(*s, **kwargs).view(type(self))
ValueError: cannot reshape array of size 0 into shape (0)

[woo...@gmail.com]

Hi Dave

I should add that I am not very erprienced with python

This is a scrpit I have copied from the internet and adapted

It works with MSG and Metop data but not with NOAA20 - I get a blank map in the wrong projection with no data

Regards

Graham

[Adam Dybbroe]

Graham,

Satpy can read these files! So, since you are here, why not use Pytroll libraries?

from satpy import Scene
from satpy.utils import debug_on
debug_on()
    

SST_FILES = ["/path/to/your/SST/file/S-OSI_-FRA_-MTOP-NARSST_FIELD-202204061000Z.nc"]

scn = Scene(filenames=SST_FILES, reader='ghrsst_l2')
scn.load(['sea_surface_temperature'])

# Here we resample to the area "euron1", but you can take any area already defined in the "areas.yaml" file

local_scn = scn.resample('euron1')

local_scn.show('sea_surface_temperature')

-Adam

To view this discussion on the web, visit https://groups.google.com/d/msgid/pytroll/18047abc-3ebc-43c8-b4f0-61ef53c92650n%40googlegroups.com.

-- 
Adam Dybbroe,
Satellite Remote Sensing Scientist
Research lead - Nowcasting and Remote Sensing
Meteorological Research unit, Research and Development
Swedish Meteorological and Hydrological Institute (SMHI)
www.pytroll.org
nwcsaf.smhi.se
www.smhi.se

[woo...@gmail.com]

Hi Adam

Thanks for the reply

I wasnt aware that you could do that with netcdf files - I will try it tomorrow

Can you do this with all SST netcdf  files from the various satellites and will it work for sea ice data too

Many thanks

Graham

[Adam Dybbroe]

The reader is supposed to handle the GHRSST netCDF format, and I know it reads the OSISAF NAR SSTs (Metop and JPSS) and also the SLSTR SSTs.

I haven't tried it myself on the Sea Ice parameters. But as you can see it at least reads the Sea Ice fraction which is part of the SST files:

In [3]: scn.available_dataset_names()
Out[3]:
['latitude_osisaf',
 'longitude_osisaf',
 'sea_ice_fraction',
 'sea_surface_temperature']

Good luck!

-Adam

To view this discussion on the web, visit https://groups.google.com/d/msgid/pytroll/3b436957-776f-4d2e-97ed-a6ffba9011afn%40googlegroups.com.

[woo...@gmail.com]

Hi Adam

I now have an image which I have attached

I dont know how to add colour,coastlines and the colour scale bar to my image - its all black and grey

 My python skills arent quite there yet

Warm Wishes

Graham