The mesosphere lies above the stratosphere and extends to an altitude of about 85 km. This is layer is often referred to as the cold layer, as the lowest readings in the atmosphere are found here. Temperature decreases with height, reaching a minimum average value of -90 ºC at the top of the layer. Temperature decreases with altitude in two of Earth's atmospheric regions: the troposphere and the mesosphere. The troposphere is the region closest to the ground, and the mesosphere is just above the ozone layer. Mesosphere, altitude and temperature characteristics like tropospheric temperature, mesospheric temperature characteristically decreases with increasing height. The top of the mesosphere is the coldest area of the Earth's atmosphere because temperature may locally decrease to as low as 100 K (-173°C).

Mesosphere, altitude and temperature characteristics like tropospheric temperature, mesospheric temperature characteristically decreases with increasing height. The top of the mesosphere is the coldest area of the Earth's atmosphere because temperature may locally decrease to as low as 100 K (-173°C). The mesosphere lies above the stratosphere and extends to an altitude of about 85 km (Ahrens 13). This is layer is often referred to as the cold layer, as the lowest readings in the atmosphere are found here. Temperature decreases with height, reaching a minimum average value of -90 ºC at the top of the layer. As the density of the gases in this layer decrease with height, the air becomes thinner. Therefore, the temperature in the troposphere also decreases with height in response. As one climbs higher, the temperature drops from an average around 62°F (17°C) to -60°F (-51°C) at the tropopause.As air rises, air pressure drops and the gas expands. To expand, the gas needs energy which it robs from the surrounding matter. This cools off the surrounding air. Hence it becomes cold at higher altitude. Within the mesosphere, temperature decreases with increasing height, due to decreasing absorption of solar radiation by the rarefied atmosphere and increasing cooling by CO2 radiative emission. The top of the mesosphere, called the mesopause, is the coldest part of Earth's atmosphere. The layers from closest to the Earth's surface to further away are the troposphere, stratosphere, mesosphere, thermosphere (with the ionosphere), and exosphere. The temperature increases at first then decreases, and then begins to increase again through the different layers. Temperature decreases with altitude because the troposphere is warmed from below, through absorption and re-emission of incoming solar radiation by the Earth's surface, rather than being warmed from above by incoming solar radiation. Temperature decreases with altitude because the troposphere is warmed from below, through absorption and re-emission of incoming solar radiation by the Earth's surface, rather than being warmed from above by incoming solar radiation.