The Earth’s Atmosphere

Atmospheric Layers 8 layers are defined by constant trends in average air temperature (which changes with pressure and radiation), where the outer exosphere is not shown. Troposphere (down to -60 ) Tropopause Stratosphere (-60 to 0) Stratopause Mesosphere (0 to -90) Mesopause Ionosphere (-90 to over 100) Exosphere So far, we have seen that both air pressure and air density decrease with height above the earth Air temperature has a more complicated vertical profile. Look at this diagram, notice that air temp normally decreases from the surface up to about 11 km (36,000 ft) or 7 mi. This decrease in air temp with increasing height is due mainly to the fact that the sunlight warms the earth’s surface and the surface then warms the air above it. The rate at which air temp decreases with height is called Lapse Rate. The standard lapse rate is about 3.6F per 1000 ft of rise. Note this is only an average and is not always the case. There are times when air temperature actually increases with height. This condition is known as a temperature inversion. We use radiosondes to measure the day to day changes in the lapse rate.

Atmospheric Layers Tropopause separates Troposphere from Stratosphere. Generally higher in summer Lower in winter. So far, we have seen that both air pressure and air density decrease with height above the earth Air temperature has a more complicated vertical profile. Look at this diagram, notice that air temp normally decreases from the surface up to about 11 km (36,000 ft) or 7 mi. This decrease in air temp with increasing height is due mainly to the fact that the sunlight warms the earth’s surface and the surface then warms the air above it. The rate at which air temp decreases with height is called Lapse Rate. The standard lapse rate is about 3.6F per 1000 ft of rise. Note this is only an average and is not always the case. There are times when air temperature actually increases with height. This condition is known as a temperature inversion. We use radiosondes to measure the day to day changes in the lapse rate. Troposphere – Temp decrease w/ height Most of our weather occurs in this layer Varies in height around the globe, but Averages about 11 km in height. Figure 1.7

Troposphere temperature -60 deg C The troposphere is the lowest major atmospheric layer (8 km to 19 km) located from the Earth's surface up to the bottom of the stratosphere. It has decreasing temperature with height (at an average rate of 3.5° F per thousand feet (6.5 ° C per kilometer) The troposphere is where all of Earth's weather occurs

The Tropopause The boundary that divides the troposphere from the stratosphere is called the "tropopause", located at an altitude of around 8 km in the winter, to around 9 km high in the summer, and as high as 18 km- 19 km in the deep tropics. When you see the top of a thunderstorm flatten out into an anvil cloud, like in the illustration above, it is usually because the updrafts in the storm are "bumping up against" the bottom of the stratosphere

Atmospheric Layers Stratosphere (temp 0 deg C) Temperature inversion in stratosphere Ozone Layer plays a major part in heating the air at this altitude So far, we have seen that both air pressure and air density decrease with height above the earth Air temperature has a more complicated vertical profile. Look at this diagram, notice that air temp normally decreases from the surface up to about 11 km (36,000 ft) or 7 mi. This decrease in air temp with increasing height is due mainly to the fact that the sunlight warms the earth’s surface and the surface then warms the air above it. The rate at which air temp decreases with height is called Lapse Rate. The standard lapse rate is about 3.6F per 1000 ft of rise. Note this is only an average and is not always the case. There are times when air temperature actually increases with height. This condition is known as a temperature inversion. We use radiosondes to measure the day to day changes in the lapse rate. Figure 1.7

Ozone Layer Only when oxygen is produced in the atmosphere can an ozone layer form and prevent an intense flux of ultraviolet radiation from reaching the surface. There is considerable recent concern that manmade fluorocarbon compounds may be depleting the ozone layer, with dire future consequences for life on the Earth.

Stratopause is the level of the atmosphere which is the boundary between two layers: the stratosphere and the mesosphere (50 km) In the stratosphere the temperature increases with altitude, and the stratopause is the region where a maximum in the temperature occurs.

Atmospheric Layers Mesosphere (meteors burn up here) Middle atmosphere – Air thin, pressure low, Need oxygen to live in this region. Air quite Cold -90°C (-130°F) near the top of mesosphere So far, we have seen that both air pressure and air density decrease with height above the earth Air temperature has a more complicated vertical profile. Look at this diagram, notice that air temp normally decreases from the surface up to about 11 km (36,000 ft) or 7 mi. This decrease in air temp with increasing height is due mainly to the fact that the sunlight warms the earth’s surface and the surface then warms the air above it. The rate at which air temp decreases with height is called Lapse Rate. The standard lapse rate is about 3.6F per 1000 ft of rise. Note this is only an average and is not always the case. There are times when air temperature actually increases with height. This condition is known as a temperature inversion. We use radiosondes to measure the day to day changes in the lapse rate. Figure 1.7

Located 80 km above Earth’s Surface Mesopause the boundary in the earth's atmosphere between the mesosphere and the thermosphere, at which the temperature stops decreasing with increasing height and begins to increase. Located 80 km above Earth’s Surface

Atmospheric Layers Thermosphere- made up of the Ionosphere and below the Exosphere “Hot layer” – oxygen molecules absorb energy from solar Rays warming the air. Very few atoms and molecules in this Region. So far, we have seen that both air pressure and air density decrease with height above the earth Air temperature has a more complicated vertical profile. Look at this diagram, notice that air temp normally decreases from the surface up to about 11 km (36,000 ft) or 7 mi. This decrease in air temp with increasing height is due mainly to the fact that the sunlight warms the earth’s surface and the surface then warms the air above it. The rate at which air temp decreases with height is called Lapse Rate. The standard lapse rate is about 3.6F per 1000 ft of rise. Note this is only an average and is not always the case. There are times when air temperature actually increases with height. This condition is known as a temperature inversion. We use radiosondes to measure the day to day changes in the lapse rate. Figure 1.7

Thermosphere The layer directly above the mesosphere The International Space Station orbits the Earth within the middle of the thermosphere, between 330 and 435 kilometers (205 and 270 mi).

Ionosphere (Temperature is increasing) Above the mesosphere is the ionosphere (part of the thermosphere) where many atoms are ionized (have gained or lost electrons so they have a net electrical charge). The ionosphere is very thin, It lies 75-600 km (46-373 miles) above the Earth. where aurora take place, and is also responsible for absorbing the most energetic photons from the Sun, and for reflecting radio waves, thereby making long-distance radio communication possible.

Exosphere (temperature is over 100 deg C) the exosphere is the uppermost layer, where the atmosphere thins out and merges with interplanetary space. ~ 10,000 km above Earth’s surface It is located directly above the thermosphere.

Atmosphere Foldable 1 tab for each layer of the atmosphere Label the altitude Include what happens, or what is located in each layer The temperature change through out the layer The pressure Draw a picture of what is found in each layer Draw the “pauses” (tropopause, stratopause, mesopause)