Figure 8.

Flowchart of the traditional approach for developing microphysics schemes. Advances in cloud physics knowledge are rooted in a combination of laboratory experimentation, observations of natural clouds and precipitation, and theory. This cloud physics knowledge directly informs physically based parameterizations for microphysics scheme development. Because fundamental knowledge for many individual process rates is limited, particularly those for ice particles, heuristics play an important part in formulating many process rates. Scheme parameters are adjusted or “tuned” through comparisons of model output with cloud and precipitation observations, often in an ad hoc way.