-28163-01--10 20:59, [email protected] skrev: > Dear Jakob, > > To try to answer your specific query first: the correct spelling of the > standard name is lwe_thickness_of_atmosphere_water_vapor_content. You are > correct that standard names should always use the American spelling. The > units associated with this standard name are m and the explanation is as > follows: " "lwe" means liquid water equivalent. The construction > lwe_thickness_of_X_amount or _content means the vertical extent of a layer of > liquid water having the same mass per unit area. "Content" indicates a > quantity per unit area. The "atmosphere content" of a quantity refers to the > vertical integral from the surface to the top of the atmosphere. For the > content between specified levels in the atmosphere, standard names including > content_of_atmosphere_layer are used. Atmosphere water vapor content is > sometimes referred to as "precipitable water", although this term does not > imply the water could all be precipitated." Yes, I read this, and didn't quite understand why the tcwv GRIB message has cfName=lwe_thickness_of_atmosphere_water_vapor_content (using GRIB API 1.9.0)... > If you are looking for a quantity with units of kg m-2 then the standard name > to use is "atmosphere_water_vapor_content" which has the following > explanation: " "Content" indicates a quantity per unit area. The "atmosphere > content" of a quantity refers to the vertical integral from the surface to > the top of the atmosphere. For the content between specified levels in the > atmosphere, standard names including content_of_atmosphere_layer are used. > Atmosphere water vapor content is sometimes referred to as "precipitable > water", although this term does not imply the water could all be > precipitated." Excellent, I will use this name (atmosphere_water_vapor_content) instead. > Hence, the correct standard name equivalent to GRIB code 137 depends on the > units that are normally associated with that parameter, which is something I > need to check. > > Regarding your broader point, you are correct that there are differences > between the two documents - the one on the CF website was originally created > by Jonathan Gregory to demonstrate that equivalences can be made between CF > standard names and other ways of identifying parameters. I don't think it > was ever really intended as a reference document and in fact some of the > mappings are incorrect. Also, it pre-dates the use of GRIB2 as a data format. > We should probably remove it from the CF website and instead include a link > to the ECMWF table which is more up to date and which, I believe, is being > actively maintained. However, I think that some of the equivalences shown in > the ECMWF table are also not entirely correct, as demonstrated by your query. > I will pass this on to ECMWF and try to get a definitive answer to your > question. If you notice anything else in the ECMWF table that looks strange, > please let me know and I'll feed it back to them. Looking forward to hearing more...
Thanks, Jakob _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
