How does temperature change as altitude increases in Earth's atmosphere?
As altitude increases in Earth's atmosphere, the temperature generally decreases. This pattern can be explained by the concept known as the lapse rate.
The lapse rate represents the rate at which the temperature changes with respect to altitude. On average, the lapse rate in the Earth's troposphere (the layer closest to the surface) is about 6.5 degrees Celsius per kilometer or 3.6 degrees Fahrenheit per 1,000 feet.
There are a few key factors that contribute to this temperature change:
1. Decreased pressure: As you ascend in altitude, the atmospheric pressure decreases. Lower pressure means that there are fewer air molecules to absorb and retain heat energy. Consequently, the temperature decreases.
2. Adiabatic cooling: As air rises in the atmosphere, it expands due to the lower pressure. This expansion leads to adiabatic cooling, which is the cooling of air as a result of reduced pressure. The expansion causes the air molecules to spread out, which lowers their average kinetic energy and, subsequently, the temperature.
3. Absorption of solar radiation: Near the Earth's surface, the atmosphere is heated by the absorption of solar radiation. However, as you move higher, there are fewer molecules to absorb this radiation, causing less warming and contributing to the decrease in temperature.
4. Heat transfer: Another factor that affects the temperature change with altitude is heat transfer. In the lower levels of the atmosphere, heat is transferred through conduction and convection. As altitude increases, the air becomes thinner, and these heat transfer mechanisms become less efficient. Consequently, the temperature decreases.
To summarize, as you go higher in the Earth's atmosphere, the decrease in atmospheric pressure, adiabatic cooling, decreased absorption of solar radiation, and reduced effectiveness of heat transfer mechanisms result in a decrease in temperature.
As we move upwards in Earth's atmosphere, temperature changes in the following manner:
1. Troposphere: The troposphere is the lowest layer of the atmosphere closest to the Earth's surface. In this layer, temperature generally decreases with increasing altitude at an average rate of 6.5 degrees Celsius per kilometer (3.6 degrees Fahrenheit per mile). This decrease is known as the environmental lapse rate.
2. Tropopause: The tropopause is the boundary between the troposphere and the layer above it, called the stratosphere. In the tropopause, the temperature remains relatively constant or slightly increases with increasing altitude.
3. Stratosphere: Once we enter the stratosphere, the temperature starts to increase with increasing altitude. This increase is due to the presence of ozone molecules that absorb and re-emit solar radiation, resulting in a warming effect. The specific rate of temperature increase varies but is generally around 1-2 degrees Celsius per kilometer (0.5-1.2 degrees Fahrenheit per mile).
4. Stratopause and Above: Beyond the stratosphere, in the stratopause layer and higher into the mesosphere and thermosphere, temperature tends to become more complex and depends on various factors such as solar activity, composition, and energy transfer within the atmosphere. In general, the temperature remains relatively constant or increases with increasing altitude due to the absorption of high-energy solar radiation.
It's important to note that the atmosphere is a dynamic system, and temperature profiles can vary due to factors like weather patterns, geographical location, and time of year. The given information provides a general understanding of how temperature changes with altitude in Earth's atmosphere.