Chapter 1 - Understanding Weather and Climate

The gases, droplets, and particles surrounding Earth's surface

The science that studies the atmosphere

Day-to-Day conditions of the atmosphere

The statistical properties of the atmosphere, including measures of average conditions, variability, etc

The study of long term atmospheric conditions

Those gases whose relative abundance is constant within the homosphere

Gases present in amounts that vary greatly in abundance, either vertically, horizontally, or seasonally. Water vapor is the most important variable gas.

The lowest 80 km (50 mi) of the atmosphere, in which the relative abundance of the permanent gases is constant.

The highest atmosphere (above 80 km or so), where gases are not well mixed but rather are stratified according to molecular weight. Vertical motions are too weak to overcome gravitational settling, so heavier gases are found beneath lighter gases.

Nitrogen is a stable gas that accounts for 78 percent of the volume of all permanent gases, or 75.5 percent of their mass.

Oxygen constitutes 21 percent of the volume of the atmosphere and 23 percent of its mass.

Argon makes up most of the remainder of the atmosphere (about 1 percent).

Water in its gaseous phase, not to be mistaken for small water droplets. Colorless and orderless, it seldom (rarely) amounts to more than a few percent of the total atmospheric mass.

The perennial (perpetual) movement of water in its 3 phases between the atmosphere, Earth's surface, and ground water.

An important variable gas in the atmosphere, made up of one atom of carbon bound to two atoms of oxygen. An important greenhouse gas.