Unit 3: Atmosphere & Climate: Notes - 9th Grade

Atmosphere

The layer of gases surrounding Earth, primarily composed of nitrogen (78%) and oxygen (21%).

Volcanic Outgassing

The process by which gases trapped in the Earth's interior are released into the atmosphere through volcanic activity.

Troposphere

The lowest layer of the atmosphere where weather occurs, containing most of Earth's air and water vapor.

Coriolis Effect

The effect of Earth's rotation on the direction of winds and currents, causing them to curve.

Albedo

The measure of reflectivity of the Earth’s surface, ranging from 0 (no reflection) to 1 (total reflection).

Greenhouse Gases

Gases in the atmosphere, such as carbon dioxide and methane, that trap heat and contribute to the greenhouse effect.

Oxygen Catastrophe

The event when the oxygen produced by photosynthetic organisms became abundant, drastically changing Earth's atmosphere and killing many anaerobic organisms.

Thermohaline Circulation

Ocean circulation driven by temperature and salinity differences, crucial for regulating the Earth's climate.

Carbon Cycle

The process through which carbon is exchanged between the Earth's biosphere, geosphere, hydrosphere, and atmosphere.

Climate Proxies

Preserved physical characteristics of the past, such as ice cores or tree rings, used to infer historical climate conditions.

Banded Iron Formations (BIFs)

Layers of sedimentary rock indicating periods when oxygen levels rose in Earth's atmosphere and reacted with iron.

Photosynthesis

The process by which green plants and cyanobacteria convert sunlight, carbon dioxide, and water into glucose and oxygen.

Biomes

Large ecological areas on the Earth's surface, with flora and fauna adapting to their environment, such as forests, deserts, and tundras.

Thermal Energy

The total internal energy of an object due to the kinetic energy of its molecules.

Heat Transfer

The process by which thermal energy moves from one place to another, including conduction, convection, and radiation.

Endosymbiosis

A symbiotic relationship where one organism lives inside another, which is thought to be a process in the evolution of eukaryotic cells.

Heat Budget

The balance between the amount of heat energy entering and leaving the Earth’s atmosphere.

Ice Ages

Periods of long-term reduction in Earth's temperature during which continental ice sheets and glaciers expand.

Eccentricity

The measure of how much an orbit deviates from being circular, affecting Earth's climate over a cycle of approximately 100,000 years.