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The density of the Earth's atmosphere decreases nearly exponentially with altitude. The total mass of the atmosphere is M = ρ A H ≃ 1 kg/cm 2 within a column of one square centimeter above the ground (with ρ A = 1.29 kg/m 3 the atmospheric density on the ground at z = 0 m altitude, and H ≃ 8 km the average atmospheric scale height).
The thermosphere is the second-highest layer of Earth's atmosphere. It extends from the mesopause (which separates it from the mesosphere) at an altitude of about 80 km (50 mi; 260,000 ft) up to the thermopause at an altitude range of 500–1000 km (310–620 mi
These layers are the troposphere, stratosphere, mesosphere, and thermosphere. The troposphere is the lowest of the four layers and extends from the surface of the Earth to about 11 km (6.8 mi) into the atmosphere, where the tropopause (the boundary between the troposphere stratosphere) is located. The width of the troposphere can vary depending ...
where R is the ideal gas constant, T is temperature, M is average molecular weight, and g 0 is the gravitational acceleration at the planet's surface. Using the values T=273 K and M=29 g/mol as characteristic of the Earth's atmosphere, H = RT/Mg = (8.315*273)/(29*9.8) = 7.99, or about 8 km, which coincidentally is approximate height of Mt. Everest.
T = 210 K, H = 6000 m. These figures should be compared with the temperature and density of Earth's atmosphere plotted at NRLMSISE-00, which shows the air density dropping from 1200 g/m 3 at sea level to 0.125 g/m 3 at 70 km, a factor of 9600, indicating an average scale height of 70 / ln(9600) = 7.64 km, consistent with the indicated average ...
The troposphere contains the boundary layer, and ranges in height from an average of 9 km (5.6 mi; 30,000 ft) at the poles, to 17 km (11 mi; 56,000 ft) at the Equator. [ 3 ] [ 4 ] In the absence of inversions and not considering moisture , the temperature lapse rate for this layer is 6.5 °C per kilometer, on average, according to the U.S ...
Presently "CIRA 1986" or CIRA-86 covers the height range up to 120 km as a set of tables. In the thermosphere, above about 100 km, CIRA-86 is identical to the more complicated NASA MSIS-86 model. All models are now available on the Web. The task group takes account of more recent data at bi-annual meetings in connection to COSPAR meeting.
Due to the lack of solar heating and very strong radiative cooling from carbon dioxide, the mesosphere is the coldest region on Earth with temperatures as low as -100 °C (-148 °F or 173 K). [1] The altitude of the mesopause for many years was assumed to be at around 85 km (53 mi), but observations to higher altitudes and modeling studies in ...