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Glossary

air current

A moving stream of air.

air pressure

See: Atmospheric pressure.

algae

A simple photosynthetic plant that lives in aquatic environments.

algal bloom

Occurs when algae grow very fast to accumulate into dense patches near the wateràs surface. ìHarmful algal bloomsî contain toxins or cause negative impacts.

atmospheric pressure

Pressure exerted by the mass of the atmosphere above a point on, or above, a planet as a result of gravitational attraction between the planet and its atmosphere. Low pressure indicates pressure that is below average, while high pressure indicates pressure that is above average.

barometer

An instrument for measuring atmospheric pressure.

climate

Average weather conditions of a region, including temperature, precipitation, and winds.

data

Information, often in the form of measurements or observations, which can be analyzed.datasetA collection of data over time.

decadal

On the time scale of decades, or tens of years.

dendroclimatology

The study of past climates by analyzing the annual rings of trees.

ecosystem

A community of interacting organisms and their physical environment.

El NiÃ’o

A large-scale ocean-atmosphere climate phenomenon linked to a periodic warming in sea surface temperatures across the central and east-central equatorial Pacific. El NiÃ’o represents the warm phase of the El NiÃ’o/Southern Oscillation (ENSO) cycle.

global warming

An increase in Earthàs average temperature.

greenhouse gases

Gases, primarily water vapor, carbon dioxide, ozone, nitrous oxide, and methane, which increase global temperatures by absorbing outgoing radiation emitted by the Earthàs surface. Also called GHGs.

Gulf Stream

A warm ocean current of the northern Atlantic Ocean off eastern North America. It originates in the Gulf of Mexico, then flows northward along the southeast coast of the US. North of Cape Hatteras, NC, the Gulf Stream veers northeastward into the Atlantic Ocean.

Jet Stream

A high-speed air current in the upper atmosphere.

midlatitudes

The areas between about 30∞ and 55∞ latitude, in either the Northern or Southern hemisphere.

North Atlantic Oscillation

A seesaw of atmospheric mass between the Icelandic low pressure system and the Azores high pressure system.North Atlantic Oscillation indexThe difference of normalized sea level pressure between the Azores high and the Icelandic low for a four-month winter season (December-March).

ozone

A chemically active gas, the molecule of which consists of three oxygen atoms (O 3). In the stratosphere, ozone acts as a protective barrier for Earthàs surface by absorbing much of the potentially damaging ultraviolet radiation that comes from the Sun. In the troposphere, ozone acts as a harmful pollutant and is one of the primary greenhouse gases.

salinity

The amount of dissolved salts in water.

stratosphere

The layer of the atmosphere above the troposphere. The stratosphere extends from approximately ten to fifty kilometers above Earthàs surface.

troposphere

The lowest layer of Earthàs atmosphere in contact with Earthàs surface. Most weather occurs within the troposphere. The troposphere extends from Earthàs surface to elevations of approximately 10-15 kilometers.

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