Definition of «surface air»

"Surface air" refers to the air found in the lowest layer of the earth's atmosphere, which is closest to the ground or surface.

However, over the past decade, the warming of surface air temperatures has slowed. (skepticalscience.com)
The study puts a widely reported «hiatus» in global surface air temperatures since 1998 into context. (dotearth.blogs.nytimes.com)
Firstly, what is the best estimate of the global mean surface air temperature anomaly? (realclimate.org)
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