GEOG 1112- Midterm Exam Guide - Comprehensive Notes for the exam ( 40 pages long!)
13 Oct 2017
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Document Summary
Early atmospheric composition: our early atmosphere consisted mainly of hydrogen and helium, these very light gases are believed to have escaped to space or been lost as the earth collided with other large bodies. Water vapor: the most abundant of the variable gases but can vary between 0 and 4% by volume. Important in the hydrologic cycle: clouds, precipitation (rain & snow, affects the energy balance. It accounts for a very small part of the atmosphere (~0. 040%: we sometimes refer to it in parts per million (ppm) or 440 ppm. Methane (ch4: only constitutes a small proportion of the atmosphere (0. 01 ppm or 1. 7 ppb) but is very important. It is emitted by: domesticated cattle, as a by-product of rice cultivation, from gas pipelines. In the upper atmosphere (stratosphere: essential for life because it absorbs lethal uv radiation from the sun, this is why the ozone hole is of concern, at the surface, however, ozone is a pollutant.
