New parameters for netCDF files

[Dave Offiler]

DMI (and others) have requested additional parameters to be saved in the netCDF files (we have previously decided to freeze the text format from any futher dveelopments). These being:

• BA_smooth
• T_dry
• BG_profile

The last is agreed not to be implemented, as the functionality exists in using the Level 2b part of the structure flagged as type BG instead of the default OC profile type.

T_dry is derived directly from N and is naturally on N-levels. It would be more appropriate to include this as an extra profile in Level 2a (N) than in Level 2b (T,q,P). Agreed with Kent.

BA_smooth could be added as a 4th BA profile in the Level 1b section, on the assumption that it is smoothed onto exactly the same levels as the BA_corrected (unsmoothed) profile. Any reason why this shouldn't be implemented?

For consistency with other parameters, a 'thin_method' parameter should also be added to note the method used to thin the data (if applied), e.g. 'SG-247', 'SAMPLE-250', 'NONE' etc. This could just follow the templates for existing *_method parameters.

Recommendation: implement new parameters 'thin_method', 'BA_mooth' and 'T_dry' in appropriate sections of ROtype structure and include in I/O to netCDF (but not to text) files. Must not break reading old files not having these parameters in them.

Nice to have for ROPP-1, but not essential - perhaps as part of a 1.1 upgrade.

[Dave Offiler]

After further discussion at CPT2 (Nov 2007), it was agreed that T_dry can be considered to be an alternative retrieval product, and as such should be output to a separate (netCDF) file in the Level 2b section, with an appropriate annotation in meteo_method. Therefore, T_dry will not be implemented as a new parameter.

BA_smooth has been implemented as bangle_opt (optimised BA) together with associated impact_opt, bangle_sigma and bangle_qual as new parameters in the Level 1b structure and netCDF file (but not text file). For backwards compatibility, all of these new variables are explicitly checked as existing in the netCDF before attempting to read them (and their range/units attributes). These variables are also fully supported in all ropp_ip code which processes Level 1b data (I/O, range checking, thinning...).

A new global attribute thin_method (80-chr string) has been added to the ROPP structure and netCDF file (but not text file). For backwards compatibility, this new attribute is explicitly check as existing before attempting to read from a netCDF file. The attribute is filled in by the top-level thinner routine, and contains the method ID, method title and thinner s/w version ID.

Tested using rebuilt test2ropp and ropp2ropp tools under script tests/t_ropp2ropp (part of 'make test') using ifort compiler. All new parameters being processed as expected.

[Dave Offiler]

Typos: above new Optimised BA parameter list should be: impact_opt, bangle_opt, bangle_opt_sigma and bangle_opt_qual and supported in ropp_io code

[(none)]

Milestone 1.1 deleted