ThinkRankComposition and Structure of Atmosphere
Overview
The atmosphere is a dynamic gaseous envelope held by gravity. This chapter explores its chemical composition and its vertical structure, characterized by varying temperature and pressure gradients.
Learning Objectives
- Recall the proportions of major atmospheric gases
- Distinguish between layers based on thermal characteristics
- Explain the importance of the Ozone layer and Ionosphere
- Discuss the role of trace elements like water vapor and aerosols
Key Concepts
Thermal Layering
The atmosphere is divided into the Troposphere (where weather occurs), Stratosphere (contains Ozone), Mesosphere, and Thermosphere (contains Ionosphere).
Greenhouse Gases
Trace gases like CO2 and Methane play a critical role in Earth's thermal balance by trapping outgoing longwave radiation.
Key Terms
Lapse RateIonosphereAerosolAlbedoStratopause
Examples
Normal Lapse Rate
The average decrease in temperature (6.5°C per km) with height in the Troposphere.
Quick Check
- Which layer contains the Ozone layer?
- What gas is most abundant in the atmosphere?