The Solar Connection The Coriolis Effect The Winds Choose to view chapter section with a click on the section heading. The Solar Connection The Coriolis Effect The Winds Chapter Topic Menu

The Solar Connection The Solar Connection Chapter 10 Pages 10-3 to 10-14

Air and Sun Life gets almost all its energy from the sun. It turns out that solar energy does more than provide energy for life on Earth. It drives the wind, and it drives currents in the ocean. The Earth’s surface is heated by sunlight. The sun not only powers life, but also provides the temperature conditions necessary for life. The Solar Connection Chapter 10 Pages 10-3 to 10-8

Air and Sun What is air? It’s the mixture of gases that surrounds us. Air consists of approximately 78% nitrogen. The breakdown, on average, of clean dry air is approximately: Nitrogen 78.08% Oxygen 20.95% Argon 0.93% Carbon dioxide 0.03% All other gases 0.01% The Solar Connection Chapter 10 Pages 10-3 to 10-8

This is the composition of the Troposphere Air and Sun This is the composition of the Troposphere The Solar Connection Chapter 10 Pages 10-3 to 10-8

Air and Sun Air is a mixture of gases that surround us. The four layers of the atmosphere include: Troposphere – the lowest layer. This one concerns us most; 15,000 meters (49,200 feet) Stratosphere - continues to about 50,000 meters (164,200 feet). Mesosphere - extends to about 90,000 meters (295,200 feet). Thermosphere – the top layer which goes out into space; beyond 110,000 meters (360,800 feet) The Solar Connection Chapter 10 Pages 10-3 to 10-8

Air and Sun The Solar Connection Chapter 10 Pages 10-3 to 10-8

Air and Sun Air compresses under its own weight. So, while the atmosphere extends more than 100 kilometers (approximately 70 miles) above sea level, most of the mass of the atmosphere exists close to Earth in the troposphere and the stratosphere. The effects that concern our study (air quality, weather, and air-sea interactions) take place in these layers. The Solar Connection Chapter 10 Pages 10-3 to 10-8

Air and Sun Besides its gaseous components, the atmosphere has two other components that account for about 4% of its total volume. These are water vapor and aerosols. Aerosols are liquid and solid particles suspended in the air, such as dust, pollen, or ash. The Solar Connection Chapter 10 Pages 10-3 to 10-8

Air and Sun The amount of water vapor in the air relates to air temperature, density,and pressure. As temperature rises, air pressure increases, and density decreases. Adding water vapor decreases the density even more. Warm air is less dense than cool air. Two air masses of the same temperature can have different densities depending on the amount of water vapor. These differences cause precipitation. The Solar Connection Chapter 10 Pages 10-3 to 10-8

Air and Sun Weather Fronts The Solar Connection Chapter 10 Pages 10-3 to 10-8 Weather Fronts

Air and Sun When saturated or nearly saturated air cools, its molecules vibrate more slowly. When water vapor molecules slow down enough, they condense into liquid water droplets, or into ice crystals when the temperature is sufficiently cold. Initially these droplets or crystals are very small and tend to remain suspended. However, they can collide and form bigger drops or clusters of crystals that fall as rain or snow, and you get out your umbrella or boots. The Solar Connection Chapter 10 Pages 10-3 to 10-8

Air and Sun A lot of air cooling occurs where a warm, moisture-laden air mass collides with a cooler air mass. Rain or snow falls where the two masses meet because that’s where the cold air chills the warm air, causing rain or snow to form. When you hear meteorologists talk about a weather front, they’re referring to the place where two air masses meet. Rain and snow can also occur when warm moist ocean air travels over comparatively cool land. The Solar Connection Chapter 10 Pages 10-3 to 10-8

Air and Sun From a marine science perspective, this is an important process for two reasons: One is that these movements redistribute heat around the Earth. A second is that precipitation is our primary source of fresh water. Ultimately, all aquifers (underground water), rivers, and lakes get their fresh water from rain or snow. This is the part of the hydrologic cycle that returns water from the sea back to land, giving it the potential to carry essential nutrients (including organic nitrogen) into the ocean. The Solar Connection Chapter 10 Pages 10-3 to 10-8

The Earth’s Heat Balance About 50% of all the sunlight that reaches the atmosphere makes it to Earth’s surface. To maintain balance with the heat from the sun, all the energy absorbed reradiates through various paths back into space as infrared radiation. If this process were imbalanced with more heat coming in than leaving, the Earth would grow hotter and hotter until life perished. The Solar Connection Chapter 10 Pages 10-8 to 10-9

The Earth’s Heat Balance The Solar Connection Chapter 10 Pages 10-8 to 10-9

Uneven Heating Factors that cause the Earth to heat unevenly: The Earth is round, the Earth’s axis is tilted, and the Earth’s orbit is elliptical hence the distance between the Earth and sun varies with time of year. The Solar Connection Chapter 10 Pages 10-10 to 10-14

Uneven Heating Angle of Incidence The Solar Connection Chapter 10 Pages 10-10 to 10-14 Angle of Incidence

Uneven Heating Seasonal Changes The Solar Connection Chapter 10 Pages 10-10 to 10-14

Elliptical Orbit and Heating Uneven Heating The Solar Connection Chapter 10 Pages 10-10 to 10-14 Elliptical Orbit and Heating

Uneven Heating Uneven heating causes weather – in part due to convection. Convection is vertical circular currents caused by temperature differences in a fluid such as air. Warm air becomes less dense and rises. Cool dense air comes in to replace it, which in turn warms and rises. This creates a circular airflow pattern. The Solar Connection Chapter 10 Pages 10-10 to 10-14

Uneven Heating Convection The Solar Connection Chapter 10 Pages 10-10 to 10-14 Convection

Idealized Convection Flow Uneven Heating Idealized Convection Flow The Solar Connection Chapter 10 Pages 10-10 to 10-14

The Coriolis Effect The Coriolis Effect Chapter 10 Pages 10-15 to 10-19

Deflection to the Right or Left The Coriolis effect is the tendency for the path of a moving object to deflect to the right in the Northern Hemisphere and to deflect to the left in the Southern Hemisphere. The Coriolis Effect Chapter 10 Page 10-15

The Earth’s Rotation The Coriolis effect is caused by the Earth’s rotation relative to an object in motion over its surface. Motion or lack of motion is relative to the place from which you observe it. Standing on the equator relative to anyone on the Earth, you’re motionless. Someone at a fixed point in space would say you’re moving. To that person, you are moving because the Earth is rotating. The Coriolis Effect Chapter 10 Pages 10-16 to 10-18

The Earth’s Rotation Relative Motion The Coriolis Effect Chapter 10 Pages 10-16 to 10-18

The Earth’s Rotation Apparent Deflection The Coriolis Effect Chapter 10 Pages 10-16 to 10-18

The Earth’s Rotation Major Ocean Gyres: The Coriolis effect creates circular airflow and current patterns such as the major ocean gyres – in the Northern Hemisphere to the right and in the Southern Hemisphere to the left. The Coriolis Effect Chapter 10 Pages 10-16 to 10-18

The Winds The Winds Chapter 10 Pages 10-19 to 10-25

The Coriolis Effect and the Wind The Coriolis effect deflects the air to the right in the Northern Hemisphere. This gives the air a circular flow pattern rather than a straight north-south pattern. The Winds Chapter 10 Pages 10-19 to 10-21 Global circulation.

The Coriolis Effect and the Wind Atmospheric circulation cells are six distinct air masses (three in each hemisphere) with individual air flow patterns. Of the six cells, the most important are the Hadley cells. These lie between the equator and approximately 30° north or south latitude. The Winds Chapter 10 Pages 10-19 to 10-21

The Coriolis Effect and the Wind Trade winds are caused by air rising at the equator and moving northward. The air becomes dense enough from cooling and moisture loss to sink. Most of the air descends and flows back toward the equator, deflecting westward as it flows. The Winds Chapter 10 Pages 10-19 to 10-21

The Coriolis Effect and the Wind Between 30° and 60° latitude are the Ferrel cells. They exist because some of the wind that descends from the Hadley cells doesn’t turn toward the equator. Instead it continues on toward the poles shifting to the right (Northern Hemisphere) as it moves. This is what causes the “Westerlies,” getting this name because they’re from the west. The Winds Chapter 10 Pages 10-19 to 10-21

Intertropical Convergence Zones and Atmospheric Heat Engine The geographic equator is 0° latitude. The meteorological (ITCZ) equator is an imaginary line marking the temperature equilibrium between the hemispheres that shifts north and south of the geographic equator with seasonal changes. The Winds Chapter 10 Pages 10-21 to 10-22

Intertropical Convergence Zones and Atmospheric Heat Engine The ITCZ equator is important because atmospheric and ocean circulation are approximately symmetrical on either side of it – not at the geographic equator. The Winds Chapter 10 Pages 10-21 to 10-22

Intertropical Convergence Zones and Atmospheric Heat Engine The Earth’s major deserts are found at 30° latitude. Here the downward vertical airflow brings dry air to the Earth’s surface. This leads to areas with little rainfall and significant evaporation. Where the ocean is alongside deserts, the combination of high evaporation and low rainfall makes the salinity of these waters higher than average. The Winds Chapter 10 Pages 10-21 to 10-22

Intertropical Convergence Zones and Atmospheric Heat Engine The Winds Chapter 10 Pages 10-21 to 10-22 The World’s Major Deserts

Monsoons and Cyclones Monsoons are seasonal wind pattern changes caused by heating or cooling on the continents. Monsoons cause summers with significant rainfall and winters with very little. Cyclones are large rotating storm systems of low pressure air with converging winds at the center. There are two main types: extratropical and tropical. Extratropical cyclones occur where the Polar and Ferrel cells meet. Tropical cyclones form within a single atmospheric cell. The Winds Chapter 10 Pages 10-22 to 10-24

Monsoons and Cyclones In both cases, cyclones form when moist wind gets drawn into a low-pressure area, causing it to twist around on itself. Cyclones appear to rotate the “wrong” way with respect to the Coriolis effect. When a cyclone forms, the low pressure pulling the wind into the pattern is stronger than the Coriolis effect. The winds that get drawn in and provide the cyclone energy are pulled away from the Coriolis effect. This imparts the “backwards” spin. Cyclones help with the redistribution of heat that is important to all life on Earth. The Winds Chapter 10 Pages 10-22 to 10-24

Monsoons and Cyclones A Tropical Cyclone Hurricane Katrina The Winds Chapter 10 Pages 10-22 to 10-24

Extratropical Cyclone Formation Monsoons and Cyclones Extratropical Cyclone Formation The Winds Chapter 10 Pages 10-22 to 10-24