As you know, sometime we need some more output variables to study the issues. But i'm not good at the Netcdf I/O system.  I want  adding more variables in the output file (such as RAD files), so i just read the code and add my own output variables which follow the original variables in the RAD file. but after running some days, it go wrong with the message: NetCDF: Index exceeds dimension bound.  And i check the output files, it shock me that all the files (original files and the adding variables files) were wrong, it's just a mess!!! I'm so depressed and work hard to find out the reasons, but a week has been past, i make little  progress. 

     Did someone has done this before? In this situation, what need to pay special attention. Otherwise, is there a specification or guidance steps for this condition.