GRIB-API definition
name | 2 metre relative humidity | Abbreviation | 2r | Unit | % | paramId: | 260242 |
UERRA details
Definition | The ratio of the partial pressure of water vapour to the equilibrium vapour pressure of water at the same temperature near the surface. |
Validity | |
Comment | Please note that the specific height level above ground might vary from one Centre to another. |
WMO GRIB2 definition
Parameter | ||
---|---|---|
Discipline | 0 | meteorological products |
Parameter Category | 1 | moisture |
Parameter Number | 1 | relative humidity |
Level | ||
---|---|---|
Type of first fixed surface | 103 | specified height level above ground (m) |
Scale factor of first fixed surface | 0 or 1*** | (m) or (dm***) |
Scaled value of first fixed surface | 2 or 15*** | 2 / 1.5 m |
Type of second fixed surface | all bits to 1 | missing |
Scale factor of second fixed surface | all bits to 1 | missing |
Scaled value of second fixed surface | all bits to 1 | missing |
*** option valid for MetOffice
6 Comments
Richard Mladek
It would be consistent with up-to-now approach to call this parameter "2 metre relative humidity" (with abbreviation 2r) in GRIB-API. The more general name "Surface air relative humidity" would be beneficial sometimes as some centres measure at 1.5m height.
Sebastien Villaume
I don' t see how you could resolve having one paramId but 2 definitions, one for 2m and one for 1.5m ....it would work for getting a paramid out of the message but which one should be picked when you set the paramId?
The only solution I could think of is to add centre=74 explicitly in the concept and have this one appearing before the default one in paramId.def.
what do you think Shahram Najm?
Shahram Najm
We can adopt the same approach as we did for params 121,167,168 and the override for the UKMO (their TWO metre XX is actually 1.5 metres!)
Sebastien Villaume
lets do it then
Sebastien Villaume
Shahram Najm: should I create a specific issue for this? (since you create a specific one for cloud cover in %)
Shahram Najm
Yes please. Raise a JIRA issue