Deducing the general circulation from basic concepts and a few empirical facts

The general circulation of the Earth's atmosphere is complex, linking a wide range of scales and physical processes. This special issue samples current research on a wide range of properties of the general circulation. This introductory article provides a context in which to place these articles by listing some principal balances such as: conservation of mass and momentum. Some implications and constraints are briefly described. The general circulation may be broadly deduced from those primary physical balances, dynamical constraints, and a few empirical facts (primarily the distribution of precipitation).