What's the difference between extratropical and ultratropical?

Extratropical

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Definition:

• (a.) Beyond or outside of the tropics.

Example Sentences:

• (1) The structure and processes of the urban atmosphere in extratropical regions are briefly described.

Ultratropical

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Definition:

• (a.) Situated beyond, or outside of, the tropics; extratropical; also, having an excessively tropical temperature; warmer than the tropics.

Example Sentences: