Thermal layer
A thermal layer was a region found within the atmosphere of a gas giant.

In 2154, Arik Soong had a Denobulan medical ship Barzai and its pilot jettisoned into the atmosphere of a gas giant, where it became trapped between two thermal layers, forcing the starship  to break off their pursuit of Soong and mount a rescue. ()

In 2372, the  slipped between two thermal layers were speeds were easier to mange. The Defiant later passed into another thermal layer, where it encountered the Karemma and the Jem'Hadar. ()

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Meteorology