7: Earth's Atmosphere
- Page ID
- 55007
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- 7.1: Overview of Earth’s Atmosphere
- This page explains the importance of solar radiation in driving Earth's processes and weather patterns while detailing the composition and structure of the atmosphere, primarily nitrogen and oxygen. It describes how air pressure decreases with altitude and how temperature, a measure of kinetic energy, typically decreases as well. It also provides information on temperature scales and conversions, highlighting the significance of Kelvin in scientific measures.
- 7.2: Layers of the Atmosphere
- This page explains the vertical structure of Earth's atmosphere, detailing how pressure, density, and temperature vary with altitude across different layers: troposphere, stratosphere, mesosphere, and thermosphere. It highlights the troposphere's role in weather, the stratosphere's temperature inversions due to ozone, the coldness of the mesosphere, and the hot, low-density thermosphere.
- 7.3: Weather and Climate: What’s the Difference?
- This page explains the difference between weather and climate, highlighting that weather pertains to short-term atmospheric conditions, while climate refers to long-term weather patterns. It uses clothing choices as an example to illustrate the impact of each concept, noting that weather affects daily attire and climate influences broader purchasing decisions. Recognizing these distinctions is essential for discussions about climate change.
- 7.4: Radiation
- This page explains radiation as electromagnetic waves generated by electric and magnetic fields, categorized by wavelength into types like radio waves and x-rays. It highlights the inverse relationship between wavelength, frequency, and temperature: colder objects emit lower frequencies and longer wavelengths, while warmer objects emit higher frequencies and shorter wavelengths. This principle is consistent across various temperature scales, from near absolute zero to millions of Kelvins.
- 7.5: Earth-Sun Energy Balance
- This page explains the energy balance between the Earth and the Sun, focusing on how temperature differences affect radiation. The Sun emits shortwave ultraviolet radiation due to its high temperature, while Earth emits longwave infrared radiation. This process is linked to the electromagnetic spectrum and Planck’s law, indicating that hotter bodies emit shorter wavelengths.
- 7.6: Air Pollution
- Ozone is ozone no matter where it is in the atmosphere. Good ozone is good only because it is in the stratosphere where we cannot breathe it. Bad ozone also absorbs solar ultraviolet light, but it is down near Earth's surface where we can breathe it. For UV protection, we are interested in the total number of ozone molecules between us and the Sun. 90% of ozone molecules are in the stratosphere and 10% are in the troposphere - some down near Earth's surface where we can breathe them.
Chapter 7: Earth's Atmosphere — Introduction
In the astronomy portion of this course, we examined Earth as one world in a much larger universe. We now turn our attention toward Earth itself, beginning with the atmosphere that surrounds our planet. Although this marks the beginning of our study of meteorology, it also builds directly on ideas we have already encountered. Energy from the Sun drives many of the processes that occur in Earth's atmosphere, while the interaction of radiation with Earth's surface and atmosphere helps determine the planet's temperature.
In this chapter, we will examine the composition and structure of the atmosphere, distinguish between weather and climate, and explore how radiation moves through the Earth-Sun system. These ideas will provide the foundation for understanding the atmospheric processes and weather systems developed in the chapters that follow. We will also consider air pollution as an example of how changes in atmospheric composition can affect both the environment and human health.