text: Jacob (1999) classifies CTMs as [http://acmg.seas.harvard.edu/people/faculty/djj/book/bookchap3.html#pgfId=108713 Eulerian/"box"] or [http://acmg.seas.harvard.edu/people/faculty/djj/book/bookchap3.html#pgfId=107525 Lagrangian/"puff"] models, depending on whether the CTM in question focuses on
  * (Eulerian) "boxes" through which fluxes, and in which chemical production/loss and deposition occur over time
  * (Lagrangian) the production and motion of parcels of air ("puffs") over time
  An Eulerian CTM solves its continuity equations using a global/fixed frame of reference, while a Lagrangian CTM uses a local/moving frame of reference.