Earth's Atmosphere: The mesosphere and stratosphere

Earth’s Atmosphere: The mesosphere and stratosphere

Below the mesopause at an altitude from 95 km (60 miles) to 55 km (35 miles) is the “mesosphere” layer of the Earth’s atmosphere. At the top of the mesosphere, the temperature is around -80 ° C (-112°F).

Earth's Atmosphere

In this zone millions of meteors melt and vaporize while entering the atmosphere and collide with gas particles, so even here there can be found suspended particles of heavy metals such as iron, potassium, silicon and other refractory materials.

MeteorShower

The mesosphere absorbs the electromagnetic radiation of X-rays and ultraviolet rays between 121 and 1 nm during the day, which makes this zone a a point of recombination and release of ions and electrons generating electric currents mainly thunders which cause chemical reactions as combination and separation of molecules.

Noctilucent cloud

Due to the high rate of chemical reactions the mesosphere is an unstable and active region where  carbon dioxide, oxides of nitrates, and water crystals are formed emitting radiation which tries to escape from the “mesosphere” to the “thermosphere” thus maintaining low temperatures that are affected by the convection of the troposphere and the stratosphere.

In the bottom of the “mesosphere” temperature is around -20 ° C (-4°F). This area es where the ionosphere ends.

Ionósfera

Between 50 km (30 miles) and 55 km (35 miles) of altitude is the “stratopause” where the pressure begins to be noticeable with about 1/1000 atmospheres (0.015 psi) and a temperature that reaches -15 ° C (5°F).

Estratósfera

The “stratosphere” starts at an altitude of 50 km (30 miles). This is a dynamically stable layer without convection or regular  turbulence, a temperature at the top of around -3 ° C (27°F), predominantly composed of nitrogen oxide molecules (nitrogen dioxide) and carbon oxides (carbon monoxide) forming stable layers.

The “stratosphere” contains the ozone layer.

Stratosphere and Ozone Layer

From an altitude of  35 km (20 miles) to 45 km (30 miles) during the day a certain amount of ultraviolet rays interact with nitrogen oxides (mainly nitrogen dioxide NO2), by composing and decomposing to allow quick formation of 1-Oxygen ion, O2 , and O3. This is the start of 10% of the “ozone layer” which blocks about 99% of ultraviolet radiation from the sun to lengths less than 300 nanometers.

Capa de Ozono

The presence of methane (CH4) in this layer may lead to the formation of compounds which can destroy ozone.

methane_strip

 

At an altitude from 35 km (20 miles) to 20 km (12 miles) the temperature rises to nearly -40 ° C (-40°F). In this area starts the bottom of the ozone layer which is a cold region where 90% of the ozone (O3) layer is with concentrations of 0.6 ppm.

In this area there is a little amount of UV rays, ozone is not formed, and there is no atomic oxygen found.

Ozone__simp_modified

Overnight, the ozone O3 reacts with nitrogen dioxide to form the NO3 or even N2O5 in the presence of water. Sunlight will form nitric acid and hydroxyl radicals OH HNO3 that descend to the troposphere.

The presence of nitrogen proliferates in a diatomic form of N2  which is hardly reactive, but which is combined with oxygen (forming  nitrogen dioxide NO2) and hydrogen in the presence of electrical currents, forming nitric acid, ammonia (with available hydrogen ions) and oxides (with oxygen ions in the night, for example amounting to NO3 forming the stratosphere) which in turn are easily decomposed into N2 by electric currents allowing the formation of ozone and nitric acid HNO3 to return to the Earth’s surface by condensation or by means of precipitation.

Aurora Boreal en Capa de Ozono

At this altitude, temperatures are around -55 ° C and kept constant to the tropopause.

Tropopausa