Why Aqua-Planet GCM? We want fo find a "dynamical" structure of global climate (= How it rains)? Strategy construct a hypothetical earth gather and classify atmospheric circulation patterns with various "external" parameters orbital parameters, size of planet, rotation rate etc. hopefully distinguish Cause and Result if set-up is simple enough. Simplest earth with "climate" = Aqua-Planet covered with a global ocean (no land) atmospheric water cycle included