atmqty Manual: AtmQty qty Quantities Data Structure

All atmospheric quantitites are stored in the attribute qty. (Note that boundary condition attributes, like p0 and T_surf, are not considered an "atmospheric quantity" and are thus not stored in qty.) By using only the methods defined in the AtmQty object to manipulate object attributes, it's easier to write more robust and portable code. Thus, by manipulating the quantities data structure qty with methods designed for that purpose (e.g. add_qty), you'll write better code. I've tried to do this in all the components I've written for this package.

That being said, currently the qty data structure is a plain-old Python dictionary. Thus, the lines:

>>> T_pot = x.qty['theta']

and

>>> T_pot = x.get_qty('theta')

are identical.

Each atmospheric quantity is input, stored, and accessed as a rank 3 Numeric array where the first index cycles through latitude, the second index through longitude, and the third index through level. This is similar to how MATLAB would index such a rank 3 data structure. Note that in Python, however, commonly you'll find rank 3 latitude-longitude-level data structures (for instance as directly read in from a netCDF dataset) will index first through level, second through latitude, and finally through longitude.