I have got some information from weather specialists and they confirm that:
the old GFS v 14 had already a native resolution of 13km same as the new GFS FV3 v 15. This is the computational resolution.
It is confirmed by NOAA :
« GFS Version 15.1 maintains a horizontal resolution of 13 km and has 64 levels in the vertical extending up to 0.2 hPa »
The old GFS was dispatched to users by GRIB files with a 0.25° resolution. And this is not changed with the new GFS FV3 v 15.
Note that 0.25° is close to 27 km, when 23 km is 0.2°
Alas, planting a trillion trees won't save the planet from climate change:
Planting trees is a wonderful idea, but it isn't enough and it isn't fast. We still have to cut our carbon emissions.
Could anyone explain why there is such a concentration of NO2 between the French coast and Corsica when selecting the CAMS 40km model compared to the CAMS EU 10km model? In the observed case the difference is about 10 times higher.
How can a model of low resolution (40km) show figures so high that a model of higher resolution (10km) does not detect. While the regional multi-models ensemble used by CAMS EU does not operate in the same way as the CAMS global model, these differences seems to be a bias.
We know there are many ferries and big cruise ships between the coast and Corsica, but what content of NO2 should be considered in this region?
(I have observed these big differences for several days now, and same issue in Algeria and Tunisia).