Rangi: weather and climate glossary

Were there any terms you didn't know in any of these lessons? We explain some of them here - alphabetically from anemometer to wind speed.

Anemometer: A tool that meteorologists use to measure wind speed.

Barometer: An instrument that records air pressure.

Buoys: A weather station that floats in the ocean. Some buoys are locked in one place, while others are free to float around the oceans on their own. Buoys can provide weather information like air temperature, wind speed and the temperature of the ocean water. 

Climate: Trends in the atmosphere over long time frames such as months or years. 

Climate drivers: Atmospheric influencers of general weather patterns that occur over longer timescales like weeks or months.

Cloud: A visible mass of condensed water vapour floating in the atmosphere.

Condense: The process by which water vapour turns back into a liquid.

Continental ice sheet: glacial ice that covers land masses. Greenland, East Antarctica and West Antarctica.

Cold front: A weather feature that divides warm air and cool air, moving so that the cooler air replaces the warmer air.

Doppler radar: This instrument looks a bit like a giant satellite dish and sends out pulses of energy that bounce off rain droplets and return to the radar site. This lets us see where rain is falling, even if it’s hundreds of kilometres away.

Drought: a prolonged period with little or no rainfall that causes dry soils, low river flows and limitations on available water for use.

El Niño: During an El Niño event, ocean water from off the west coast of South America (near Ecuador and Peru) to the central tropical Pacific warm above average. The warming takes place as trade winds (the permanent east-to-west prevailing winds that flow around the equator) weaken or even reverse, blowing warm water from the western Pacific toward the east.

El Niño Southern Oscillation: ENSO for short. A naturally occurring climate cycle that includes three phases: El Niño, La Niña, and neutral that occurs every few years. 

Firn: crushed, condensed and compressed snow that is on the way to becoming ice.

Glacier: a perennial formation of snow, firn, ice, air and debris that forms in a cold, alpine or polar environment.

High pressure: Areas in the atmosphere where the air sinks toward the ground, leading to dry, pleasant weather.

La Niña: During a La Niña event, ocean water from off the coast of South America to the central tropical Pacific cools to below average temperatures. This cooling occurs because of stronger than normal easterly trade winds, which churns cooler, deeper sea water up to the ocean’s surface.

Low pressure: Areas in the atmosphere where the air rises into the sky, usually leading to rainy or stormy weather.

Madden-Julian Oscillation: an eastward moving pulse of cloud and rainfall in the tropics that typically has a life cycle of 30 to 60 days. It is the largest element of changeability of the weather in the tropics.

Meteorologist: A scientist who studies and predicts the weather.

Molecules: A molecule is the smallest unit of a substance (for example water) that can exist. If a molecule were split into smaller pieces, it would be a different substance.

Moraine: a ridge of sediment made of mud, sand, gravel, and boulders that is plowed into place at the edge of an advancing glacier. Moraines are left behind when the ice retreats.

Precipitation: rain or any other solid form of atmospheric water that condenses and falls from the sky on to the ground.

Pressure melting: the overlying weight of thick ice causes an increase in pressure at the base of the ice, which concentrates heat and raises temperatures that cause melt.

Rain gauge: An instrument that records how much rain has fallen.

Snow line: a seasonally varying line on a glacier that separates a higher zone where snow from the previous winter and spring is retained and a lower zone in which snow and ice formed in the past are being melted.

Southern Annular Mode: SAM for short. Involves alternating windiness and storm activity between the mid-latitudes, where New Zealand is located, and higher latitudes, such as over the Southern Ocean and Antarctica.

Supercomputer: Huge computers that are as big as an entire room, and more powerful than 10,000 desktop computers. 

Temperature: the measure of how hot or how cold an object is.

Thermal image: a picture that shows the surface temperature of an object.

Thermometer: This instrument records air temperature.

Tornadoes: A type of storm with powerful rotating winds in a column that touches the ground. The winds in tornadoes are very strong and may exceed 400 km/h. Tornadoes can cause a lot of damage such as destroy buildings and whip cars into the air.

Tropics: The part of the world that is most directly exposed to the sun’s rays, found between 23.5˚N and 23.5˚S latitude at the geographical centre of the Earth.

Tropical cyclones: A storm with swirling clouds, strong winds and heavy rain that form in warm oceans. 

Warm front: A weather feature that divides warm air and cool air, moving so that the warmer air replaces the cooler air.

Water vapour: Water in its gaseous form (usually it’s invisible)!

Weather: The state of the atmosphere at a particular place and time.

Weather balloon: A very large balloon with instruments attached that record things like temperature, wind speed, and wind direction high in the atmosphere.

Weather observations: Observations of the state of the atmosphere at a specific time and place, including things such as temperature, wind speed, humidity, rain, snow, visibility, etc.

Weather satellite: Located in outer space, weather satellites are used to see things like cloud formations and even tropical cyclones that might be located far from land. Some satellites are so high up that they can see almost half of the earth all at once.

Weather station: a facility, either on land or sea, with instruments and equipment for measuring atmospheric conditions to provide information for weather forecasts and to study the weather and climate.

Wind: Air in motion

Wind direction: Describing where the wind is coming from.

Wind gust: A sudden increase in the wind’s speed that lasts no more than a few seconds.

Wind speed: Average speed of the wind over a set period of time, often several minutes.