We investigate 3D atmosphere dynamics for tidally locked terrestrial planets with an Earth-like atmosphere and irradiation for different rotation periods ( P _ { rot } = 1 - 100 days ) and planet sizes ( R _ { P } = 1 - 2 R _ { Earth } ) with unprecedented fine detail .
We could precisely identify three climate state transition regions that are associated with phase transitions in standing tropical and extra tropical Rossby waves .

We confirm that the climate on fast rotating planets may assume multiple states ( P _ { rot } \leq 12 days for R _ { P } = 2 R _ { Earth } ) .
Our study is , however , the first to identify the type of planetary wave associated with different climate states : The first state is dominated by standing tropical Rossby waves with fast equatorial superrotation .
The second state is dominated by standing extra tropical Rossby waves with high latitude westerly jets with slower wind speeds .
For very fast rotations ( P _ { rot } \leq 5 days for R _ { P } = 2 R _ { Earth } ) , we find another climate state transition , where the standing tropical and extra tropical Rossby wave can both fit on the planet .
Thus , a third state with a mixture of the two planetary waves becomes possible that exhibits three jets .

Different climate states may be observable , because the upper atmosphere ’ s hot spot is eastward shifted with respect to the substellar point in the first state , westward shifted in the second state and the third state shows a longitudinal ’ smearing ’ of the spot across the substellar point .

We show , furthermore , that the largest fast rotating planet in our study exhibits atmosphere features known from hot Jupiters like fast equatorial superrotation and a temperature chevron in the upper atmosphere .