What causes global atmospheric patterns to exist

One way is that the sun is heating up the world causing droughts and causing the water level to rise to cause floods

Answerhave flowing water either episodically or during only a portion of the year;

Magma forms by partial melting of upper mantle and crust. partial melt means that only a fraction of the available material forms a melt, and that the remainder stays solid. the partial melt rises because of its lower density and ascends through he crust. this is so conclusive mean the answer would be magma igneous rocks or balistic magma.