--- title: "Polar Cell | Intro to Climate Science" description: "Polar cell is the atmospheric circulation cell at high latitudes where cold air sinks, creating polar highs, dry conditions, and polar easterlies." canonical: "https://fiveable.me/introduction-climate-science/key-terms/polar-cell" type: "key-term" subject: "Intro to Climate Science" unit: "Unit 4" --- # Polar Cell | Intro to Climate Science ## Definition A polar cell is the high-latitude circulation cell where very cold air sinks over the poles, creating high pressure and dry conditions. In Intro to Climate Science, it helps explain polar easterlies and global wind belts. ## What It Is A polar cell is the circulation cell that sits at each pole in Earth's three-cell atmosphere model. In Intro to Climate Science, you can think of it as the cold end of the planet's wind engine: air sinks over the poles, spreads outward near the surface, and then returns aloft after it meets warmer air at lower latitudes. The basic setup starts with extreme cooling at the poles. Because sunlight is weaker there and snow and ice reflect a lot of incoming energy, polar air stays dense and cold. Dense air sinks, which builds a surface high-pressure area called a polar high. From there, the air flows outward toward about 60 degrees latitude. That surface flow does not move in a straight line. Earth's rotation deflects moving air to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, so the outflow becomes the polar easterlies. They are called easterlies because they blow from east to west, opposite the direction of the mid-latitude westerlies students often notice on weather maps. The cell closes when air rises again near the boundary between cold polar air and warmer mid-latitude air, often near subpolar lows. That rising branch is weaker than the rising air in the Hadley cell because the poles receive less solar energy, so the temperature contrast is smaller and the overall circulation is less energetic. This is why the polar cell is the weakest of the three major circulation cells. The dry conditions in polar regions come from the sinking branch. Sinking air warms slightly as it compresses, which lowers relative humidity and discourages cloud formation and precipitation. That is why Antarctica is often described as a desert, even though it is covered in ice. If you are tracing the bigger climate pattern, the polar cell is not isolated. It interacts with the Ferrel cell along the polar front, where sharp temperature differences can trigger storm development and shifting weather systems. So when a climate model or class diagram shows winds, pressure belts, and latitude bands, the polar cell is the piece that explains why the poles tend to have high pressure, dry air, and persistent east-to-west surface winds. ## Why It Matters Polar cell is one of the main building blocks of global atmospheric circulation, so it gives you the high-latitude half of the story when you are explaining why Earth has different climate zones. If you only memorize that the poles are cold, you miss the mechanism. The polar cell shows how cold air, sinking motion, pressure, and wind direction fit together. This term also connects several other climate ideas you will see again and again. Polar highs, polar easterlies, and the boundary with the Ferrel cell all come from the same circulation pattern. That means one concept can explain a weather map label, a climate diagram, and a short-answer question about why polar regions are so dry. It matters for climate change discussions too. As the Arctic and Antarctic atmosphere shift, the position and strength of the polar circulation can change, which can affect storm tracks, the polar front, and the way cold air spills into lower latitudes. In class discussions, that often shows up as a cause-and-effect chain, not just a definition. ## Connections ### [Polar Easterlies](/introduction-climate-science/key-terms/polar-easterlies) Polar easterlies are the surface winds produced by air moving out of the polar cell and getting deflected by Earth's rotation. If you know the polar cell, the wind direction makes sense: cold air sinks at the pole, flows outward, and becomes an east-to-west wind near the surface. ### [Polar Highs](/introduction-climate-science/key-terms/polar-highs) Polar highs are the high-pressure zones created where cold, dense air sinks over the poles. The polar cell is the circulation pattern behind those highs, so this term is the pressure-map version of the same idea. On weather diagrams, you often identify the polar cell by its high-pressure center. ### [Ferrel Cell](/introduction-climate-science/key-terms/ferrel-cell) The Ferrel cell sits next to the polar cell in the mid-latitudes. Their boundary is where warmer air meets colder polar air, which is a setup for strong weather changes. When you compare the two cells, you can see why the polar cell is colder, drier, and weaker. ### Jet Stream The jet stream is tied to strong temperature contrasts near the border between the polar cell and the Ferrel cell. Even though it flows higher in the atmosphere than the surface winds of the polar cell, both features reflect the same large-scale energy imbalance between cold polar air and warmer air farther south. ## On the AP Exam A quiz or short-answer question might show a latitude-and-pressure diagram and ask you to label the polar cell, describe why the air sinks there, or match it to polar easterlies. In a lab or data analysis task, you might use temperature and pressure patterns to explain why polar regions stay dry even though they are cold. In a climate essay, you could trace how the polar cell interacts with the Ferrel cell and the polar front to shape stormy weather near 60 degrees latitude. The main move is to connect circulation, pressure, wind direction, and climate outcome in one chain, not treat them as separate facts. ## polar cell vs Ferrel Cell The polar cell is the circulation cell nearest the poles, with sinking cold air and surface flow outward from the poles. The Ferrel cell is the mid-latitude cell between about 30 and 60 degrees, and it is driven more indirectly by the cells on either side. If you mix them up, check the latitude band and whether the air is sinking over cold poles or circulating in the middle latitudes. ## Key Takeaways - The polar cell is the high-latitude atmospheric circulation cell that starts with sinking cold air over the poles. - Its sinking branch creates polar highs, while the surface branch helps produce polar easterlies. - The polar cell is weaker than the Hadley and Ferrel cells because the poles receive less solar energy. - Dry polar climate conditions come from descending air, which reduces cloud formation and precipitation. - The polar cell matters because it connects wind belts, pressure patterns, and polar climate into one system. ## FAQs ### What is polar cell in Intro to Climate Science? The polar cell is the atmospheric circulation cell at each pole. Cold, dense air sinks there, creating high pressure and dry conditions, then flows outward at the surface before rising again near the boundary with warmer air. ### Why is the polar cell weaker than the Hadley cell? The polar cell is weaker because the poles get less incoming solar energy, so the temperature differences driving circulation are smaller. That means less rising motion, less convection, and a less energetic circulation pattern overall. ### How does the polar cell create polar easterlies? Air moves outward from the polar highs toward lower latitudes. Earth’s rotation deflects that air, so the winds end up blowing from east to west at high latitudes, which is why they are called polar easterlies. ### Why are polar regions dry if they are so cold? Cold air can hold less moisture, and the sinking air in the polar cell warms slightly as it compresses, which lowers relative humidity. That combination makes cloud formation and precipitation less likely, so polar regions can be very dry. ## Related Study Guides - [4.1 Global atmospheric circulation patterns](/introduction-climate-science/unit-4/global-atmospheric-circulation-patterns/study-guide/ZnR5iw1b4GEDjKXL) ## About This Document Canonical Fiveable pages are available as Markdown at the same path plus `.md`. - [llms.txt](https://fiveable.me/llms.txt): index of Fiveable's sections and URL patterns - [llms-full.txt](https://fiveable.me/llms-full.txt): complete subject and unit listing - [MCP server](https://fiveable.me/mcp): call Fiveable as tools instead of fetching pages (`https://fiveable.me/api/mcp`) - [MCP server for AP teachers](https://fiveable.me/mcp/teachers): a teacher's classes, assignments and AP-rubric grading (`https://fiveable.me/api/mcp/teacher`) ## Structured Data ```json {"@context":"https://schema.org","@graph":[{"@type":"LearningResource","@id":"https://fiveable.me/introduction-climate-science/key-terms/polar-cell#resource","name":"Polar Cell | Intro to Climate Science","url":"https://fiveable.me/introduction-climate-science/key-terms/polar-cell","learningResourceType":"Concept explainer","educationalLevel":"AP® / High School","about":{"@id":"https://fiveable.me/introduction-climate-science/key-terms/polar-cell#term"},"audience":{"@type":"EducationalAudience","educationalRole":"student"},"dateModified":"2026-07-03T02:22:54.414Z","isPartOf":{"@type":"Collection","name":"Intro to Climate Science Key Terms","url":"https://fiveable.me/introduction-climate-science/key-terms"},"author":{"@type":"Organization","@id":"https://fiveable.me/editorial#content-team","name":"Fiveable Content Team","url":"https://fiveable.me/editorial","parentOrganization":{"@id":"https://fiveable.me/#organization"},"member":[{"@type":"Person","name":"Amanda DoAmaral","sameAs":["https://www.linkedin.com/in/adoamaral"]},{"@type":"Person","name":"Becky Bahr","sameAs":["https://www.linkedin.com/in/becky-bahr-b52743132"]}]},"publisher":{"@type":"Organization","name":"Fiveable","url":"https://fiveable.me"}},{"@type":"DefinedTerm","@id":"https://fiveable.me/introduction-climate-science/key-terms/polar-cell#term","name":"polar cell","description":"A polar cell is the high-latitude circulation cell where very cold air sinks over the poles, creating high pressure and dry conditions. 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