upper atmosphere

Second, the upper atmosphere of Eisberg was pretty much pure hydrogen, which is somewhat easier to ionize than oxygen or nitrogen.

Clear and dry though the air is, the blue of the skies is pale owing to a light dust haze in the upper atmosphere.

Or had the Throgs tried to blast the Terran ship in the upper atmosphere, crippling it, making this a forced landing?

As the cooling progressed, however, the steam that was in the upper atmosphere began to condense and to fall in rain.

The mists had rolled away from the ground, and only the upper atmosphere remained fog-charged.