NDdiag ("New Dynamics" diagnostics) generates a wide range of diagnostics from Unified Model ouput (in PP format), assuming an "new dynamics" Unified Model (i.e. UM versions vn5.3 and onwards).

NDdiag takes as input the following basic set of UM fields, at each timestep:

Field                     STASH Code
-----------------------   ----------
surface orography         33
u component of wind       2
v component of wind       3
specific humidity         10
w-wind                    150
rho pressure levels       407
theta pressure levels     408
cloud liquid water        4205
cloud liquid ice          4206
temperature               16004

Instructions for running NDdiag

The command to run the code is:

NDdiag {Input PP file} {control file} {Output PP file}

If the latitude and longitude on both the true and rotated grids is requested, then this will be written to a file called latlon.txt. If an orography file is supplied, it will override the orography in the PP input file, if any. The control file is obtained by editing a copy of the control file that comes with the source code and deleting the diagnostics you don't want.

It should be noted that the size of the output file, and the time taken to compute it, increases with the number of diagnostics requested. If you forget how to run the command, type the command name with no arguments and hit return.

When retrieving PP files from HECToR, it is sometimes necessary to swap the bytes of the retrieved file on the local computer. This is due to differences in the architectures of the two computers.

Source Code

The NDdiag development trunk and branches are held under configuration control (Subversion) by NCAS-CMS. The NDdiag project can be found here.

Last modified 7 years ago Last modified on 30/04/13 10:27:25