Martin Rowley wrote in message ...
:Can anyone tell me how the field which I interpret to be boundary layer
:cloud fraction (Grenzschichtbewolkung)
:differs from the low cloud fraction he-
:Boundary layer:-
:http://www2.wetter3.de/GFS_00_UTC/gfs_6-12_37.gif
:Low cloud:-
:http://www2.wetter3.de/GFS_00_UTC/gfs_6-12_14.gif
:What I'm trying to work out is what vertical 'cut-off' is used - is it
:an arbitrary altitude (say 900m) or is it based upon something else? My
:very limited German is not up to the job I'm afraid.

Under the charts it simply says:
"Boundary layer cloud fraction [%] Isopleths for 5, 10, 30, 60 and 95%"
"Low cloud [%] Isopleths ... "

Is there an explanation in German somewhere else that you can't read ?

Colin Youngs
Brussels