Weather Terminology Flashcards
Atmospheric air pressure
The force exerted on the Earth’s surface by the weight of the air, measured in millibars.
Climate change
Changes in the long-term temperature and precipitation patterns that can either be natural or linked to human activities.
Climate zone
Divisions of the Earth’s climates into belts, or zones, according to average temperatures and average rainfall. The three major zones are polar, temperate and tropical.
Condensation
The process whereby rising water vapour becomes a liquid.
Coriolis effect
The result of Earth’s rotation on weather patterns and ocean currents, making storms swirl clockwise in the southern hemisphere and anticlockwise in the northern hemisphere
Drought
a prolonged period of time with unusually low rainfall: droughts occur when there is not enough rainfall to support people or crops.
El Nino
Climatic changes affecting the Pacific region and beyond every few years, characterised by the appearance of unusually warm water around northern Peru and Ecuador, typically in late December; the effets of El Nino include the reversal of wind patterns across the Pacific, causing drought in Australasia, and unseasonal heavy rain in South America.
Enhanced greenhouse effect
The exaggerated warming of the atmosphere caused by the emission of gases from human activities resulting in the natural greenhouse effect becoming more effective.
Front
A boundary separating two masses of air with different densities, usually heavier cold air and lighter warm air.
Glacial periods
Historic cold periods associated with the build-up of snow and ice and the growth of ice sheets and glaciers.
Global warming
A trend associated with climate change involving a warming trend (0.85 degrees C since 1880)
Greenhouse effect
Natural warming of the atmosphere as heat given-off from the Earth is absorbed by liquids and gases, such as carbon dioxide.
Hemisphere
A half of the earth, usually as divided into northern and southern halves by the Equator
High pressure
When there is more air pressing down on the ground, caused by air sinking; air descends as it cools, leading to high pressure at the surface.
Inter-glacial periods
Historic warm periods in-between glacial periods where conditions were much the same as they are today.
Intertropical convergence zone
A low-pressure belt that encircles the globe around the Equator; it is where the trade winds from the northeast and southeast meet; the Earth is tilted on its orbit around the Sun, causing the ITCZ to migrate between the Tropics of Cancer and Capricorn with the seasons.
Katabatic winds
Movements of cold dense air that flow downhill and along valley floors; in Antartica, most winds blow towards the coast from the centre.
Latitude
the imaginary lines that surround the Earth ranging from 0 degree at the Equator to 90 degree at the poles.
Low Pressure
Caused when the air is rising, so less air is pressing down on the ground; air rises as it warms, leading to low pressure at the surface.
Monsoon
Heavy rainfall that arrives as a result of a seasonal wind, notably in southern Asia and India between May and September
Precipitation
The collective term for moisture that falls from the atmosphere; this could be in the form of rain, sleet, snow or hail.
Prevailing wind
The most frequent, or common wind direction.
Quaternary geological period
The most recent geological period covering the last 2.6million years, during which time there were several cold and warm periods.
Rain shadow
An area or region behind a hill that has little rainfall because it is sheltered from rain-bearing winds
