Global wind patterns are large-scale air movements caused by unequal solar heating, Earth’s rotation (the Coriolis effect), and pressure gradients. Intense equatorial heating creates rising air at the ITCZ; that air moves poleward aloft and sinks around 30° latitude (the subtropical high), forming the Hadley cell. Between 30° and ~60° the Ferrel cell and between 60° and the poles the Polar cell complete the three-cell circulation. As air moves horizontally, the Coriolis effect deflects winds: surface trade winds blow from the NE/SE toward the equator, westerlies blow poleward in mid-latitudes, and polar easterlies blow from the poles. Convection, pressure-gradient force, and these deflections produce features like doldrums and the subtropical jet stream. For APES, you should be able to explain this chain (equatorial heating → density/pressure differences → convection + Coriolis) as in ERT-4.E. Review the Topic 4.5 study guide (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI) and try practice questions (https://library.fiveable.me/practice/ap-environmental-science).

The equator gets the most intense solar radiation because sunlight strikes that region more directly (near 90°) year-round, so incoming energy is concentrated on a smaller surface area and travels through less atmosphere. That stronger equatorial heating warms air, lowering its density and pressure so it rises at the Intertropical Convergence Zone (ITCZ). Rising warm air drives atmospheric convection and creates the Hadley cell circulation: air rises at the equator, moves poleward aloft, sinks in the subtropics, and returns as trade winds. Those density and pressure differences plus Earth’s rotation (the Coriolis effect) shape global wind patterns like trade winds and westerlies. This chain—equatorial heating → density/pressure differences → convection and Coriolis—is exactly what the CED emphasizes for Topic 4.5 (ERT-4.E). For a quick review, check the Topic 4.5 study guide (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI) and more practice questions (https://library.fiveable.me/practice/ap-environmental-science).

Sunlight is strongest at the equator, so air there heats, becomes less dense, and rises. That rising air creates a low-pressure zone (the Intertropical Convergence Zone/doldrums). As it rises it cools and spreads toward the poles, then sinks around 30° latitude forming subtropical highs (this loop is the Hadley cell). Similar loops at mid- and high-latitudes are the Ferrel and Polar cells. Air moves from high to low pressure (pressure-gradient force), but because Earth rotates the Coriolis effect deflects those moving air masses to the right in the Northern Hemisphere and left in the Southern. Combined, these processes make the trade winds (easterly), the westerlies, and the polar easterlies, and set up features like the subtropical jet stream. This is exactly what EK ERT-4.E.1 asks you to explain. For a quick review, see the Topic 4.5 study guide (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI) and try practice questions (https://library.fiveable.me/practice/ap-environmental-science).

The Coriolis effect is the apparent deflection of moving air (and other moving objects) caused by Earth’s rotation. Because Earth spins eastward, air traveling north or south keeps the original east–west speed of its latitude, so in the Northern Hemisphere winds are deflected to the right and in the Southern Hemisphere to the left. That deflection doesn’t create wind—the pressure gradient (from hot equatorial air rising to cooler poles) and convection do—but Coriolis changes the wind’s direction. On a global scale this helps form the trade winds (east-to-west in the tropics), the westerlies (west-to-east in mid-latitudes), and the polar easterlies, and it shapes the Hadley, Ferrel, and Polar cells described in EK ERT-4.E.1. For APES, you should be able to link equatorial heating → pressure/density differences → atmospheric convection → Coriolis-induced deflection → the major wind belts (use the Topic 4.5 study guide for a clear diagram: https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI). For extra practice, try problems at https://library.fiveable.me/practice/ap-environmental-science.

Air moves because warm air is less dense than cold air. At the equator intense solar radiation heats surface air, lowering its density and pressure so that air rises (ITCZ/intertropical convergence zone). That rising air creates a pressure gradient: surrounding higher-pressure air moves toward the low-pressure zone. This pressure-gradient force drives horizontal wind. As the rising equatorial air cools aloft it flows toward higher latitudes, sinks around 30° (forming the subtropical high), and returns at the surface as trade winds—creating Hadley, Ferrel, and Polar cells (atmospheric convection cells). The Coriolis effect deflects these poleward and equatorward winds, producing trade winds, westerlies, and polar easterlies instead of straight north–south flow. These are the processes listed in EK ERT-4.E.1 on the CED and are commonly tested on the APES exam. For a compact review, see the Topic 4.5 study guide (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI) and try practice problems (https://library.fiveable.me/practice/ap-environmental-science).

Trade winds and westerlies are different wind belts tied to different convection cells and latitudes. Trade winds form between the equator and ~30° (Hadley cell). Air rises at the ITCZ/doldrums, moves poleward aloft, sinks at the subtropical high, then flows back toward the equator. Because of the Coriolis effect, that surface flow is deflected east-to-west: northeast trades in the Northern Hemisphere and southeast trades in the Southern. Westerlies form roughly between 30° and 60° (Ferrel cell). Air at the surface moves poleward from the subtropical high toward the subpolar low and is deflected west-to-east by the Coriolis effect, producing prevailing winds from the southwest in the Northern Hemisphere and from the northwest in the Southern. For APES, know the cell names (Hadley, Ferrel), the role of equatorial heating, pressure gradients, and Coriolis (CED EK ERT-4.E.1). Review this topic guide (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI) and try practice questions (https://library.fiveable.me/practice/ap-environmental-science).

Air wants to move from high pressure to low pressure because of the pressure gradient force, but two things make that flow curve instead of going straight. 1) Coriolis effect: Earth’s rotation deflects moving air to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. That deflection increases with wind speed and with distance from the equator, so air moving toward a low gets turned into the trade winds, westerlies, or polar easterlies (Hadley, Ferrel, Polar cell patterns). 2) Friction: Near Earth’s surface, friction with land/ocean slows winds and reduces the Coriolis deflection, so surface winds cross isobars at an angle toward lower pressure instead of perfectly along them. On the AP exam you should tie pressure-gradient force, Coriolis effect, and friction together when explaining atmospheric circulation (Topic 4.5). For a clear study guide on these ideas, check the Topic 4.5 study guide (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI).

Global wind patterns start because the Sun heats the equator more than the poles. Warm equatorial air rises (low pressure near 0°), flows poleward aloft, cools and sinks around ~30° (creating subtropical highs). That rising–sinking loop is the Hadley cell; similar Ferrel (30°–60°) and Polar (60°–90°) cells complete the picture. Air moves from high to low pressure (pressure gradient), but Earth’s rotation bends those flows—the Coriolis effect—deflecting winds right in the Northern Hemisphere and left in the Southern. Combined, these produce trade winds near the equator, westerlies in mid-latitudes, and polar easterlies. Zones like the ITCZ (doldrums) and subtropical highs explain persistent calm or strong winds and affect rainfall and the subtropical jet. This is exactly what the CED describes (EK ERT-4.E.1); study the cell latitudes, wind names, and Coriolis direction for the exam. More review: Fiveable’s Topic 4.5 study guide (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI) and Unit 4 overview (https://library.fiveable.me/ap-environmental-science/unit-4). For practice, try their question bank (https://library.fiveable.me/practice/ap-environmental-science).

Earth’s rotation causes the Coriolis effect, which deflects moving air to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. Combined with strong equatorial heating (strongest solar radiation at the equator), this deflection shapes the large convection cells (Hadley, Ferrel, Polar). Air rises at the Intertropical Convergence Zone (ITCZ), moves poleward aloft, sinks at the subtropical high, and returns at the surface—but the Coriolis effect turns those returning surface winds into the northeast and southeast trade winds, the mid-latitude westerlies, and the polar easterlies. Pressure-gradient force still drives air from high to low pressure, but rotation changes the wind’s direction, not its existence. For APES, you should be able to explain that density differences from equatorial heating plus the Coriolis effect produce global wind patterns (ERT-4.E.1). Review the Topic 4.5 study guide on Fiveable for diagrams and practice (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI) and try practice questions (https://library.fiveable.me/practice/ap-environmental-science).

Major global wind belts form from three convection cells per hemisphere (Hadley, Ferrel, Polar) plus the Coriolis effect. Near the equator, strong solar heating creates the Intertropical Convergence Zone (ITCZ)/doldrums and the Hadley cell: air rises at the equator, moves poleward aloft, cools, sinks at the subtropical high (~30° N/S). Surface winds from the subtropical highs toward the equator become the trade winds (NE trades in Northern Hemisphere, SE trades in Southern) because of the Coriolis deflection. Between ~30° and ~60° are the Ferrel cell and the westerlies (midlatitude surface winds from the west). Poleward of ~60° the Polar cell produces sinking cold air and the polar easterlies. These patterns set pressure gradients, drive atmospheric convection, influence the subtropical jet stream, and matter for AP questions about circulation and the Coriolis effect. For a focused study guide and practice, see Fiveable’s Topic 4.5 study guide (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI) and unit resources (https://library.fiveable.me/ap-environmental-science/unit-4).

Think of air like a fluid: when the equator gets the most intense solar heating, that air warms, expands, and becomes less dense, so it rises. Rising air creates a low-pressure zone at the surface (the ITCZ/doldrums). Cooler, denser air from higher latitudes moves in to replace it—that horizontal movement is wind (driven by the pressure-gradient force). The rising air cools aloft, spreads toward the poles, sinks around 30° (forming subtropical highs), and flows back toward the equator at the surface—that loop is the Hadley cell. Similar cells (Ferrel, Polar) form farther poleward. The Coriolis effect turns those north–south flows into the trade winds, westerlies, and polar easterlies, so global wind patterns result from density-driven convection + pressure gradients + Earth’s rotation. For AP phrasing, this ties to ERT-4.E (equatorial heating → density differences → Coriolis). Review the Topic 4.5 study guide (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI) and try practice questions (https://library.fiveable.me/practice/ap-environmental-science).

Because the Sun heats the equator more than the poles, air at the equator warms, becomes less dense, and rises. That rising air creates low pressure at the surface and sets up large convection loops—the Hadley, Ferrel, and Polar cells—which transport air poleward and back. The pressure-gradient force drives air from high to low pressure, so surface winds flow in predictable belts (trade winds, westerlies, polar easterlies). The Coriolis effect (Earth’s rotation) then deflects those flows to the right in the Northern Hemisphere and left in the Southern, turning straight north–south motions into the familiar east–west wind belts. Features like the subtropical high and the ITCZ make some regions persistently calm (doldrums) or windy. These organized drivers—equatorial heating, pressure gradients, convection cells, and Coriolis—produce consistent global wind patterns instead of random directions. For AP review, see the Topic 4.5 study guide (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI) and practice questions (https://library.fiveable.me/practice/ap-environmental-science).

Global wind patterns shape weather and climate by moving heat and moisture around Earth. Intense equatorial heating drives atmospheric convection and creates three circulation cells in each hemisphere (Hadley, Ferrel, Polar). Rising air at the ITCZ produces heavy tropical rainfall; descending air in the subtropical highs makes many deserts (30° latitude). Surface winds (trade winds, westerlies, polar easterlies) plus the Coriolis effect turn air right in the Northern Hemisphere/left in the Southern, steering storm tracks and the subtropical jet stream. Pressure-gradient forces set wind speed; regions like the doldrums (ITCZ) have weak winds and lots of rain. Long-term climate patterns (e.g., persistent westerlies) determine where storms and coastal upwelling occur, which affects marine productivity and regional climates. For AP review, link these ideas to EK ERT-4.E.1 and the Topic 4.5 study guide (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI). For more context, see the Unit 4 overview (https://library.fiveable.me/ap-environmental-science/unit-4) and practice Qs (https://library.fiveable.me/practice/ap-environmental-science).

At the equator, strong solar heating warms air, lowering its density and pressure so it rises (convection) at the Intertropical Convergence Zone (ITCZ). That rising air cools aloft, moves toward higher latitudes, and helps form the Hadley cell; some air sinks near ~30° latitude creating the subtropical high. Rising equatorial air and the Coriolis effect drive trade winds (CED EK ERT-4.E.1). At the poles, air is cooled, becomes denser and higher pressure, and sinks. That sinking polar air flows equatorward at the surface, producing the polar easterlies; between polar and mid-latitudes the Ferrel cell and westerlies form where air rises and falls differently. These pressure and density differences plus the Coriolis effect set global wind patterns. For more review on Hadley/Ferrel/Polar cells, trade winds, and subtropical highs, check the Topic 4.5 study guide (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI) and extra practice (https://library.fiveable.me/practice/ap-environmental-science).

Memorize wind belts with a layered, visual routine—think cells from Equator to Poles and the surface winds they produce. Steps: (1) Draw three cells per hemisphere: Hadley (0–30°), Ferrel (30–60°), Polar (60–90°). (2) Label pressures: equatorial heating → low at ITCZ/doldrums; 30° → subtropical high (horse latitudes); polar high at poles. (3) Add Coriolis: winds deflect right in NH, left in SH. That gives trade winds (NE trades in NH, SE trades in SH) blowing from 30° toward equator, westerlies (30°→60°) in mid-latitudes, and polar easterlies (from poles to 60°). Say it aloud while sketching—repetition locks it in. On the exam, they expect you to connect equatorial heating, pressure gradients, convection (Hadley cell), and the Coriolis effect (EK ERT-4.E.1). Practice with diagrams and question sets in the Topic 4.5 study guide (https://library.fiveable.me/ap-environmental-science/unit-4/global-wind-patterns/study-guide/eVG86e42B0MvmzUs3FYI) and more practice problems (https://library.fiveable.me/practice/ap-environmental-science).