Standardising notation

[jagoosw]

As discussed on Slack, it would be helpful if we wrote a notation page like NumericalEarth and Breeze have to standardise notation.

I'll start a draft in a comment below and people are welcome to contribute.

[jagoosw]

Notation	Code	Location	Long name
$P$	P	model.tracers	Phytoplankton (when there is only one phytoplankton)
$DIC$	DIC	model.tracers	Dissolved Inorganic Carbon
$Alk$	Alk	model.tracers	Total alkalinity
$Chl$	Chl		Chlorophyll

[jagoosw]

Maybe we should sort by parameterisation and/or figure out a way to standardise. For example we call particulate organic matter either POM if there is one with one element, PON/POC/... for one when we are explicitly representing different elements, or sPOM/bPOM for small and big, etc. but this doesn't scale or standardise