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derive 100m winds out of ECHAM files

Added by Kristina Froehlich about 1 year ago

Hi,
is there a way, to get 100 m winds out of ECHAM data? My frist attempt was just to use "ml2hl" with a couple of lower levels, but the method did not recognise the ground height. So my next attempt would be to use somehow the lowest geopotential height level, divide by 9.81 and add this to the all vertical levels. But I don't know, how I can change manipulate the level. And apart from this, is this the best possible approach?
May be this question has been raised before but I was not successfull in digging it out ...

thank you very much in advance, Kristina


Replies (1)

RE: derive 100m winds out of ECHAM files - Added by Uwe Schulzweida 9 months ago

Hi Kristina,

Sorry for the late response!
In CDO version 2.4.0, the intlevel function has been extended so that any 3D coordinates can be interpolated vertically.
The geopotential height can be used to interpolate 3D fields to user defined height levels. Here is an example with ECHAM data:

ECHAMDATA=ECHAM5_T42L19.nc
cdo after $ECHAMDATA wind.nc <<EOF
code=131,132
type=20
EOF
cdo gheight -sp2gp $ECHAMDATA gheight.nc
cdo intlevel,level=100,zvarname=zh -merge wind.nc gheight.nc wind100.nc
zvarname=zh is the variable name of the geopotential height in gheight.nc.
Here, all 3D variables are on model full-levels. Target levels outside the range of the model levels can't be calculated and will be set to missing.

Cheers,
Uwe

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