Nodes of different colours represent the following:
Solid arrows point from a submodule to the (sub)module which it is
descended from. Dashed arrows point from a module or program unit to
modules which it uses.
collision efficiency for snow collecting cloud water from Wang and Ji (2000)
https://doi.org/10.1175/1520-0469(2000)057<1001:CEOICA>2.0.CO;2
equating melted snow diameter to effective collision cross-section
Nodes of different colours represent the following:
Solid arrows point from a procedure to one which it calls. Dashed
arrows point from an interface to procedures which implement that interface.
This could include the module procedures in a generic interface or the
implementation in a submodule of an interface in a parent module.