The phrase "upper atmosphere" refers to the higher region of the Earth's atmosphere, which is located above the lower atmosphere closer to the ground. Full definition
Overall, significant improvements over previous models are seen, particularly in upper atmosphere temperatures and winds, cloud heights, precipitation, and sea level pressure. (pubs.giss.nasa.gov)
However, in cooler temperatures, the water vapor in the planet's upper atmosphere blocks the light of specific wavelengths which come from deeper layers towards space. (hngn.com)
The predicted upper atmosphere hot spots have not been found. (newscientist.com)