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Spin-up issues
Info

Description:
The largest spin-up issues occurs during the first 2 hours of the forecast. It is therefore recommended to primarily use the 6 hourly analysis fields whenever this is possible. Also, it seems that three hourly values can be used without larger restriction. The spin-up problems are most pronounced during turbulent conditions, for example connected to deep low pressure systems, and should therefore be limited in space and time.

These spin-up problems are in some situations causing too high wind speeds for the 1-2 hour forecasts. This is most pronounced in the wind gust but the problem also occurs for the mean wind at 10 meter altitude. Similar problems can be seen for maximum/minimum temperature. Then in general there is a spin-up problem for precipitation. Here, it is not recommended to use the first 6 hours of the forecasts. Therefore, if a user wants to use the 24 hour accumulated precipitation it is recommended to use the 30-6 hour forecasts.

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Info

Description:

The sensible heat flux and surface latent heat flux fields  appear to have missing values over the land and because of that should not be used.

Overestimation of global radiation and Underestimated cloud cover
Info

Description:
For global radiation, there is a general overestimation over Europe. The bias is largest over the ocean parts of the North Atlantic and decreases towards the south. It is suspected that the overestimation of global radiation can be a consequence of underestimated cloud cover and investigations are ongoing.

Overestimation of relative humidity affecting cloud cover
UERRA-HARMONIE produces too much moisture. This is a known problem for the ALADIN model. The excess of moisture does affect the cloud cover.

Geopotential height, some time steps errouneous
For geopotential height, it seems that some time steps are erroneous. The values seem wrong by a factor of 10.000. The reason for this sporadic error is unknown. Users reported errors for the following days: 1st and 2nd of January 1981, 1st – 4th of August 1981, and 11th of February 1982.

Land-sea mask to be used to downscale MESCAN-SURFEX fields

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