Atmosphere and Climate
Structure and energy
The atmosphere is layered: troposphere (weather), stratosphere (ozone layer), mesosphere, thermosphere. Insolation varies with latitude and season because of Earth's axial tilt (about 23.5°). The greenhouse effect keeps the surface warm; albedo and cloud cover affect energy balance.
Circulation and pressure
Global circulation features the Hadley, Ferrel and Polar cells, trade winds, westerlies and polar easterlies, the ITCZ, subtropical highs and the polar front. Pressure belts shift with the seasons. Local winds (breezes, föhn, bora) and cyclones versus anticyclones are frequent exam topics: cyclones bring unsettled rising air, anticyclones bring settled sinking air.
Moisture and climate types
Warm air holds more moisture; rising air cools and condenses. Relief (orographic) rainfall, convectional rainfall and frontal rainfall are distinct. Climate classification (Köppen-style) rests on temperature and precipitation patterns, giving tropical, arid, temperate, continental and polar types.
Traps
Do not confuse weather (short-term) with climate (long-term averages); remember that the troposphere cools with height while the stratosphere warms; and note that the ITCZ follows the sun, shifting north in July and south in January.
Worked example
Why is a mountain's windward slope wet and its leeward slope dry? Air is forced up, cools, condenses and rains on the windward side; descending air warms and dries on the leeward side (rain shadow).