Unit 4 - The Atmoshpere

Albedo

Percentage of light reflected by a surface

Scattering

The process by which light is redirected in multiple directions as it passes through particles in the atmosphere.

Greenhouse effect

The warming of Earth's surface due to the trapping of heat by greenhouse gases in the atmosphere.

Layers of the atmosphere from the ground up

Troposphere, stratosphere, mesosphere, thermosphere

Surfaces that reflect sunlight

Ice

water

clouds

Surfaces that absorb sunlight

Land

Forests

Oceans

How is ozone formed?

Ozone is formed when ultraviolet (UV) light from the sun splits oxygen molecules (O2) into individual oxygen atoms (O). These free oxygen atoms then react with other oxygen molecules to form ozone (O3).

Atmospheric pressure

The force exerted by the weight of air above a particular point, usually measured in millibars (mb) or inches of mercury (inHg). It decreases with increasing altitude.

Ocean breezes

Ocean breezes, also known as sea breezes, are cool winds that blow from the ocean to the land during the day, caused by the temperature difference between the land and water.

Land breezes

Land breezes are cool winds that blow from the land to the ocean during the night, caused by the temperature difference between the land and water.

Composition of the atmosphere

The atmosphere is composed predominantly of nitrogen (78%), oxygen (21%), and trace amounts of other gases, including argon, carbon dioxide, and water vapor.

Earth's primordial composition (4.5 billion years ago)

Initially, Earth was composed largely of molten rock with minimal atmospheric gases. Over time, heavier elements sank to form the core, while lighter elements formed the mantle and crust.

Earth's early atmosphere (4.5 to 3 billion years ago)

The atmosphere was primarily made up of hydrogen, helium, and volcanic gases such as water vapor, carbon dioxide, and ammonia. This period lacked free oxygen.

Formation of oceans (around 3 billion years ago)

As Earth cooled, water vapor in the atmosphere condensed to form oceans, which contributed to changes in the chemical composition of the atmosphere.

The Great Oxidation Event (around 2.4 billion years ago)

Photosynthetic organisms began producing oxygen, which significantly increased the levels of oxygen in the atmosphere, altering its composition.

Modern atmosphere (present day)

Today, the atmosphere is composed predominantly of nitrogen (78%), oxygen (21%), with trace amounts of other gases, including argon, carbon dioxide, and water vapor.

Mountain breezes

Mountain breezes occur at night when cooler air from the mountain slopes descends into the valleys, creating a temperature difference that generates wind.

Valley breezes

Valley breezes occur during the day as warmer air rises from the valley floors, creating a gentle breeze flowing up the mountain slopes.

Coriolis effect

The apparent deflection of moving objects, such as air and water, due to the rotation of the Earth, causing them to curve to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Impact of Coriolis effect on weather patterns

The Coriolis effect influences wind patterns and ocean currents, contributing to the formation of cyclones and anticyclones.

Coriolis effect in the Northern Hemisphere

In the Northern Hemisphere, moving air and water are deflected to the right, resulting in clockwise rotation of weather systems.

Coriolis effect in the Southern Hemisphere

In the Southern Hemisphere, moving air and water are deflected to the left, resulting in counterclockwise rotation of weather systems.

Doldrums

The Doldrums, also known as the Intertropical Convergence Zone (ITCZ), are located near the equator, approximately between 5° North and 5° South latitude, where the trade winds from the northern and southern hemispheres converge.

Horse Latitudes

Horse Latitudes are located around 30° North and 30° South latitudes, where the subtropical high-pressure systems create calm winds and often dry conditions.

Subpolar Lows

Subpolar Lows are found around 60° North and 60° South latitudes, where warm and cold air masses meet, leading to low-pressure systems characterized by stormy weather.