The Atmosphere and Climate Atmosphere Atmosphere The mixture

The Atmosphere and Climate

Atmosphere

Atmosphere • The mixture of gases that surrounds Earth • Nitrogen, oxygen, carbon dioxide, and other gases are all parts of this mixture • These gases are constantly added and removed

Composition of the Atmosphere • 78% Nitrogen • 21% Oxygen

Not just gases • The atmosphere also contains atmospheric dust (many types of tiny, solid particles) in addition to gases. • Atmospheric dust can include: – Soil – Salt – Ash – Pollen – Bacteria and viruses – Aerosols – tiny liquid droplets

Layers of the Atmosphere • Four layers: – Troposphere – Stratosphere – Mesosphere – Thermosphere

Troposphere • The atmospheric layer nearest the surface of the Earth • It extends to 18 km above Earth’s surface

Stratosphere • The layer above the troposphere • Where the ozone layer is located

Mesosphere • The layer above the stratosphere • Extends to an altitude of about 80 km

Thermosphere • Layer of the atmosphere furthest from Earth’s surface

Temperature in the Atmosphere

Energy and Heating • Three mechanisms transfer energy from the sun: – Radiation – Convection – Conduction • Radiation - the transfer of energy across space and in the atmosphere • Convection - the transfer of heat by air currents. Hot air rises and cold air sinks. • Conduction - the flow of heat from a warmer object to a colder object when the objects are placed in direct physical contact

Heating Earth • Our planet only receives about two-billionths of the sun’s energy • About half the energy that reaches the atmosphere will pass though to Earth’s surface

Weather and Climate

The Earth Has Many Different Climates (1) • Weather • Climate • Air circulation in lower atmosphere due to:

The Earth Has Many Different Climates (2) • Currents – Prevailing winds – Earth’s rotation – Redistribution of heat from the sun

Natural Capital: Generalized Map of the Earth’s Current Climate Zones

Global Air Circulation

Coriolis Effect

Energy Transfer by Convection in the Atmosphere

Connected Deep and Shallow Ocean Currents

Thermohaline Circulation

Global Air Circulation, Ocean Currents, and Biomes

Greenhouse Gases Warm the Lower Atmosphere • Greenhouse gases – H 2 O – CO 2 – CH 4 – N 2 O • Greenhouse effect • Human-enhanced global warming

Flow of Energy to and from the Earth

The Earth’s Surface Features Affect Local Climates • Heat absorption by land water • Effect of – Mountains • Rain shadow effect – Cities • Microclimates

Rain Shadow Effect