About This Chapter
Atmospheric Pressure and Wind - Chapter Summary and Learning Objectives
In this chapter, you'll learn all about atmospheric pressure: what it is, how it's measured, which variables affect it and how to calculate it. You'll also explore the three levels of atmospheric circulation and find out how driving and surface winds are created. By the end of this chapter, you should be able to:
- Explain horizontal and vertical changes in air pressure.
- Convert between atmospheres and mm Hg.
- Use a barometer, anemometer and wind vane.
- Differentiate between super geostrophic and subgeostrophic wind flow.
|Weather Variables: Air Pressure, Temperature & Density||Describe high and low pressure centers.|
|The General Circulation of the Atmosphere||Describe the general circulation of the atmosphere.|
|Pressure: Definition, Units and Conversions||Define pressure and learn to convert among units of pressure.|
|Dalton's Law of Partial Pressures: Calculating Partial & Total Pressures||Use Dalton's law of partial pressure to calculate partial and total pressures. Use it to explain how to find the partial pressure of a gas collected over water.|
|Defining & Describing Atmospheric Pressure||Define and describe atmospheric pressure.|
|How Altitude Affects Air Pressure||Discuss how air pressure varies with altitude.|
|The Ideal Gas Law and the Gas Constant||Use the kinetic molecular theory to explain relationships among gas, volume, temperature and pressure. Use the ideal gas law to calculate the pressure, volume, temperature or amount of gas when the other three are known.|
|Using the Ideal Gas Law: Calculate Pressure, Volume, Temperature or Quantity of a Gas||Rearrange the ideal gas law to calculate the temperature, pressure, volume or quantity of gas given the other three variables.|
|How Pressure is Measured & How it Affects the Atmosphere||Describe how pressure is measured, and determine how the atmosphere is affected by pressure. Introduce the concept of barometric pressure and pressure as a force.|
|Identifying & Describing the Levels of Atmospheric Circulation||Identify and describe the three levels of atmospheric circulation: primary, secondary and tertiary.|
|Driving Wind: Horizontal & Vertical Pressure Gradients||Explain the concepts of horizontal and vertical pressure gradients and hydrostatic equilibrium. Describe how pressure gradients drive wind.|
|Factors that Affect Wind: Pressure Gradient Forces, Coriolis Effect & Friction||Describe factors that affect wind pressure, including pressure gradient forces, Coriolis effect and friction with the surface of Earth.|
|The Flows of Geostrophic Wind||Discuss geostrophic wind. Learn about geostrophic flow, gradient flow, and super geostrophic and subgeostrophic flow.|
|Understanding How Surface Winds are Created||Discuss surface winds and factors that create them.|
|Weather Patterns Associated with Cyclones & Anticyclones||Describe how cyclones and anticyclones develop. Discuss weather patterns associated with cyclones and anticyclones. Discuss ridges and troughs.|
|Measuring Wind Using Anemometers & Wind Vanes||Explain how to measure wind via anemometers and wind vanes. Discuss units of measurement and conversion, weather map symbols and observations.|
1. Weather Variables: Air Pressure, Temperature & Density
Weather is influenced by a number of factors. In this lesson, you will learn about three key variables that control weather and how they work together to do so.
2. The General Circulation of the Atmosphere
The Sahara Desert, tropical rainforests, and cold polar winds are all due to Earth's rotation. In this video lesson, you will learn how this rotation has created global air circulation patterns on Earth and how it is responsible for such diverse climate patterns across the globe.
3. Pressure: Definition, Units, and Conversions
Have you ever wondered what pressure is and how it gets measured? In this lesson, we are going to define pressure and explain some of the units that are used to express measurements of pressure.
4. Dalton's Law of Partial Pressures: Calculating Partial & Total Pressures
In this lesson, you will learn how gases behave when they are mixed together and how to use Dalton's law of partial pressures to calculate partial and total pressures of gases. You will also learn how to use this information to explain how to find the partial pressure of a gas collected over water.
5. Atmospheric Pressure: Definition & Effects
Atmospheric pressure is around us all of the time. The air you are breathing has weight, and although it doesn't weigh a lot, there is a lot of it around. This lesson will cover atmospheric pressure and its effects.
6. The Effect of Altitude on Air Pressure
If you've ever had a headache when heading to high altitude or flying on an airplane, you were suffering from the effects of lowered air pressure with altitude. Learn why air pressure decreases with altitude and the equations that govern these effects.
7. The Ideal Gas Law and the Gas Constant
Have you ever wondered why the pressure in your car's tires is higher after you have been driving a while? In this lesson, we are going to discuss the law that governs ideal gases and is used to predict the behavior of real gases: the ideal gas law.
8. Using the Ideal Gas Law: Calculate Pressure, Volume, Temperature, or Quantity of a Gas
In another lesson, you learned that the ideal gas law is expressed as PV = nRT. In this video lesson, we'll go one step further, examining how to rearrange the equation to solve for a missing variable when the others are known.
9. Barometric Pressure, Measuring Atmospheric Pressure & Barometers
This lesson examines the causes of varying barometric pressure and how we measure them. After this lesson, you should better understand where barometric pressure values come from and why we care.
10. The Three Levels of Atmospheric Circulation
Air in the atmosphere circulates in three convection cells from north to south. This lesson looks at the formation of these different air cells and what they mean for global weather and atmospheric circulation.
11. Factors That Affect Wind: Pressure Gradient Forces, Coriolis Effect & Friction
In this video lesson, you will learn about wind and some factors that affect it, such as air temperature and pressure, the Coriolis effect, and friction. By the end of this lesson, you will also understand how Earth's rotation plays a role in how winds travel.
12. Development of Geostrophic Winds
The dominant forces of pressure gradient force and Coriolis force combine to form geostrophic wind flows. In this lesson, we'll examine why many of the winds in the atmosphere actually blow parallel to the prevailing isobars.
13. How Surface Winds Are Created
Surface winds are the winds that you feel outside near the surface of the Earth. This lesson looks into why winds exist in some locations and not others and also at the driving forces for these winds.
14. Cyclones & Anticyclones: Ridges & Troughs
Rotating air in the atmosphere can create some of the most destructive weather patterns on earth. This lesson will examine how some of these cyclonic patterns form and what they mean for our weather forecasts.
15. Measuring Wind Using Anemometers & Wind Vanes
You've likely seen anemometers and wind vanes many times around where you live but haven't associated them with the wind speeds you hear reported on the news. This lesson looks into how we determine wind speed and direction with modern technology.
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