The main atmospheric layer near the surface of the earth is

Concept

Earth's atmosphere is layered by height and how temperature changes with altitude. The troposphere is the lowest layer, sitting in direct contact with Earth's surface. It extends from the ground up to roughly 8 to 18 kilometres (lower over the poles, higher over the equator), and within it temperature falls as altitude increases while nearly all weather activity occurs.

Application

The question asks for the atmospheric layer nearest the surface. Because the troposphere begins exactly at ground level and holds about 75 to 80 percent of the atmosphere's total mass along with almost all of its water vapour, it is the layer that lies immediately against Earth's surface, confirming troposphere as the correct choice.

Cross-check

• The stratosphere sits directly above the troposphere, from the tropopause up to about 50 kilometres, and houses the ozone layer; it is not in contact with the surface.

• The mesosphere lies above the stratosphere, roughly 50 to 85 kilometres up, and is the coldest atmospheric layer, far from the surface.

• The ionosphere is defined by ionised particles spanning roughly 60 to 1000 kilometres, overlapping the upper mesosphere and the thermosphere; it sits well above, not near, the surface.