In a numerical weather prediction model with a horizontal grid resolution of 50 km, convective cloud processes are parameterized, because
GATE XE - 2018,
Answer: D
Convection is parameterized because cloud size is much smaller than the grid size.
Individual convective clouds and their updrafts are a few hundred metres to a few kilometres across. A model with a 50 km grid cannot resolve them, so their collective effect on heating, moistening and rainfall within each grid box must be represented in terms of the resolved variables: a parameterization.
Cloud physics is well understood, and models do handle phase change; the problem is scale, not knowledge. If clouds were larger than the grid they would be resolved explicitly and need no parameterization.
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