Thermosphere gas and the ionospheric plasma. The International Space Station orbits the Earth within the middle of the thermosphere, between . It is convenient to separate the atmospheric regions according to the two temperature minima at about 12 km altitude (the tropopause) and at about 85 km (the mesopause) (Figure 1). The thermosphere (or the upper atmosphere) is the height region above 85 km, while the region between the tropopause and the mesopause is the middle atmosphere (stratosphere and mesosphere) where absorption of solar UV radiation generates the temperature maximum near 45 km altitude and causes the ozone layer. The density
Polar ecology the snow making the polar regions cold. When the radiation is reflected, the heat is also reflected. The polar regions reflect 89-90% of the sun radiation that the earth receives. And because Antarctica is closer to the sun at perihelion, it receives 7% more radiation than the Arctic. Also in the polar region, the atmosphere is thin. Because of this the UV radiation that gets to the atmosphere can cause fast sun tanning and snow blindness. Polar regions are dry areas; there is very little precipitation due to the cold air. There are some times when the humidity may be