AP®︎ Environmental Science: Topic 4.4 Flashcards
Master key terms and definitions for Topic 4.4 of AP Environmental Science – Earth’s Atmosphere to help you prep for quizzes and the AP exam.
Earth’s Atmosphere
The gravitationally bound envelope of gases surrounding Earth
The gravitationally bound envelope of gases surrounding Earth
Atmospheric air with variable water vapor excluded; its standard composition is about 78% N₂, 21% O₂, 0.93% Ar, and 0.04% CO₂ by volume
The most abundant atmospheric gas, making up about 78% of dry air
The second-most abundant atmospheric gas, making up about 21% of dry air
An unreactive noble gas that makes up about 0.93% of dry air, making it the third-most abundant atmospheric gas
A trace atmospheric gas making up about 0.04% of dry air, or approximately 400 ppm
A variable atmospheric gas ranging from nearly 0% to about 4%, concentrated mainly near the surface in warm, humid air
Gases present in very small atmospheric concentrations that can still have major environmental effects
Solid particles or liquid droplets suspended in the atmosphere, such as dust, smoke, sea salt, pollen, and soot
The lowest layer, extending to about 10–12 km, where temperature decreases with altitude and nearly all weather occurs
The average decrease in tropospheric temperature with altitude, approximately 6.5°C per kilometer
The transition between the troposphere and stratosphere, near the altitude where temperature stops decreasing and begins increasing
The layer from about 10–12 km to 50 km where temperature increases with altitude because ozone absorbs ultraviolet radiation
The ozone-rich region of the stratosphere, mainly about 15–35 km high, that absorbs most UV-C and much UV-B radiation
The transition between the stratosphere and mesosphere, near 50 km where temperature stops increasing and begins decreasing
The layer from about 50 km to 80–85 km where temperature decreases with altitude and many small meteoroids burn up
The transition between the mesosphere and thermosphere and generally the coldest region of the atmospheric temperature profile
The extremely thin layer above about 80–85 km where temperature increases as particles absorb high-energy ultraviolet radiation and X-rays
A region overlapping the upper mesosphere and thermosphere that contains ions and free electrons produced by high-energy solar radiation
The transition from the thermosphere to the exosphere, placed roughly 500–1,000 km high depending on the classification used
The outermost, extremely low-density layer, where particles are far apart and the atmosphere gradually merges with space
