Weather, Climate, and the Atmosphere
Core concepts
The atmosphere is layered: troposphere (weather), stratosphere (ozone), mesosphere, thermosphere. Weather is short-term atmospheric conditions; climate is long-term averages and patterns. Key variables include temperature, pressure, humidity, wind, and precipitation. Air pressure decreases with altitude; warm air rises and cools, forming clouds by condensation. Wind flows from high to low pressure. The Coriolis effect deflects winds. Fronts (cold, warm, stationary, occluded) bring characteristic weather. The greenhouse effect traps outgoing infrared radiation, warming the surface; human emissions intensify it. Climate change is driven by greenhouse gases, with feedbacks such as ice-albedo loss.
Traps to watch
- Using a single cold day to argue against climate change.
- Confusing the greenhouse effect (natural and necessary) with ozone depletion.
- Assuming warm air holds less moisture; warm air holds more.
- Mixing up high and low pressure and their associated weather.
- Forgetting that weather is local and short-term while climate is broad and long-term.
Worked example
A warm front approaches: warm air rides over cooler air, producing widespread clouds and steady rain, with a gradual temperature rise. A cold front produces brief, intense storms and a sharp temperature drop.
Rule of thumb
Warm air rises and cools; cooling condenses water vapor. High pressure generally means fair weather; low pressure means unsettled weather.