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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.

MO datasets (UM, UM/En)

The wind directions are wrong by exactly 180 degrees
Info

Description:
The wind directions are wrong by exactly 180 degrees (the direction is the wind is blowing to, rather than where it is blowing from) The U/V components  are not affected.

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

Description:
The UERRA-HARMONIE reanalyses need to be downscaled from 11km to 5.5km in order to drive the MESCAN-SURFEX system. For that a corresponding land-sea-mask field is needed, which is currently not archived in MARS. As a solution, please download that land-sea-mask field here. We recommend users to apply it for all the MESCAN-SURFEX fields and to focus their analysis on land points only. 

More information and an illustration of potential issues when not using the appropriate LSM can be found in the related C3S support ticket.

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Time-integrated surface solar radiation downwards
Info

Description:

The time-integrate surface solar radiation downwards which comprises of both the direct and diffuse short wave radiation reaching the Earth's surface, ought to be positive by definition. Whilst archiving, it was found that it also contains negative values that were traced back to being an artefact from the downscaling from 11 km to 5.5 km. As a work around, we would suggest setting any negative values to zero.

Météo-France datasets (MESCAN-SURFEX)

2m temperature and precipitation
Info

2m temperature:
Due to biased observational data and a too tolerant quality control, analyzed temperatures can differ severely from other most likely more realistic analysis, e.g. UERRA-HARMONIE or E-OBS. Users are requested to perform additional sanity checks when using this parameter or to switch to the T2m of the UERRA-HARMONIE system. Cold biases are particularly evident in 1965 in Poland and the UK along the coast, and also a warm bias located in 2010 in the Baltic countries. However, other regions and periods might be affected as well.


Precipitation:
Errors have been noticed in the precipitation fields for some areas and time periods. These errors are due to erroneous observations of precipitation equal to zero for long period, which did enter the assimilation procedure. Since the errors are restricted in time and space, the user has to evaluate if the studied time period or region is affected.

The wind directions are wrong by exactly 180 degrees
Info

Description:
The wind directions are wrong by exactly 180 degrees (the direction is the wind is blowing to, rather than where it is blowing from) The U/V components  are not affected.

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Soil level parameters are inverted with respect to their Y-axis

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