Glossary Terms for Weather and Climate

The next topic we have to cover for A2 geography AQA course is the Weather and Climate topic. We are going to start with the key terms and definitions you will need to read, understand and learn!
If there are other words you read in any of our posts that you don't understand fully try visiting http://www.geography-dictionary.org/ and get a definition!

Another useful website to learn and revise from is:
http://www.s-cool.co.uk/a-level/geography/weather-conditions

Obviously they are not to everyones taste but if you haven't tried it before why not give it a go, try something new today!

Adiabatic heating/cooling – The heating/cooling if a gas as a result of pressure and volume changes alone

Air mass – an air mass is an extensive body of air in which there is only gradual horizontal change in temperature and humidity at a given height

Albedo – the reflectivity of a surface

Anthropogenic – effects that are derived from human activities, as opposed to those occurring in biophysical environments without human influence

Anticyclone – an area of high atmospheric pressure. Anticyclones tend to have a very low pressure gradient and light, variable winds.

Atmosphere – the mixture of gases surrounding the earth

Atmospheric pressure – this is the force per unit area exerted against a surface by the weight of air above that surface

Carbon sink – this is a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compounds for an indefinite period

Channelling – occurs when there are urban ‘canyons’ which concentrate all airflow in one direction

Climate – the average annual patter of weather experienced by a place. It is based on records from the last 30 years and describes the seasonal pattern of temperatures and precipitation

Cold front – a boundary between warm and cold air where cold air is advancing on warm air, undercutting it and causing the warm air to rise. Fronts are associated with rainfall. 

Convectional rainfall – rainfall resulting from the uplift and subsequent cooling of air that has been heated by contact with a warm land surface

Coriolis force – the effect of the earth’s rotation on air flow

Dendrochronology – the use of the annual growth rings of trees to infer past climatic conditions. Counting the rings can also give us a date

Depression – an area of low atmospheric pressure with a roughly circular pattern of isobars that occurs in temperature latitudes

Ferrel cell – the atmospheric convection cell between the subtropical high pressure zone and the temperate low pressure zone

Geographical model – a model constructed to explain overall patterns rather than localized variations, e.g. the tri-cellular model

Global warming – a term used to describe the recent, rapid rise in global temperatures  

Greenhouse gas – an atmospheric gas that acts as a filter, allowing incoming shortwave ultraviolet and light radiation through the atmosphere but stopping long wave infrared radiation from leaving, e.g. CO₂

Hadley cell – the atmospheric convection cell between the equatorial low pressure zone and the subtropical high pressure zone

Heat budget – this is the balance between the incoming solar radiation (insolation) and outgoing radiation from the planet

Insolation – a measure of solar radiation energy received on a given surface area in a given time

Inter tropical convergence zone (ITCZ) – the low pressure equatorial region where there is rising air. It is located where the NE trade winds meet (converge with) the SE trade winds

Jet stream – a narrow belt of fast-moving air near the top of the tropopause

Lapse rate – the rate at which temperature decreases with height

Latent heat – the amount of energy released or absorbed by a substance during a change of physical state that occurs without changing its temperature

Latitude – the angular distance of a place north or south of the equator

Maritime – the influence exerted by seas and oceans. It tends to have a moderating effect on climate.

North Atlantic Drift – the northwest extension of the Gulf Stream. It brings slow-moving warm water to NW European shores

Orographic rainfall – rainfall resulting from the uplift and subsequent cooling of air over high ground

Particulate pollution – a term used to describe particles of 10 micrometres or less that are the result of human activity, particularly industrial processes and vehicle exhausts. They can include cement dust, tobacco smoke, ash and coal dust

Photochemical smog – a form of air pollution caused by a photochemical radiation between the exhaust gases of cars and sunshine

Polar cell – the atmospheric convection cell between the polar high pressure zone and the temperate low pressure zone

Prevailing wind – the most common wind direction for a location

Rossby waves – a series of waves that occur in the upper westerly winds which blow in the higher parts of the atmosphere. They occur in both hemispheres.

Sahel – this is the area between the Sahara desert in the north and the savannah in the south. It stretches across the north of the African continent between the Atlantic Ocean and the Red Sea 

Savanna – the name given to a climate which can be found in tropical sub Saharan Africa, the Brazilian Plateau and northern Australia

Subtropical high pressure – the area of high pressure found between 25^o and 35⁰ N and S of the equator

Temperate – this describes temperatures or climates with few extremes. It can also describe the latitudes between the tropics and the polar cells

Trade winds – this is a reference to the pattern of prevailing easterly surface winds found in the tropics

Tri-cellular model – A model that explains some of the main aspects of atmospheric circulation. It divides each hemisphere into three large convection cells

Tropical revolving storm – a generic term that refers to intense low pressure weather systems that originate over warm tropical oceans and migrate westward and poleward. They have a variety of names, e.g. hurricanes

Tropopause – the boundary between the troposphere and the stratosphere

Troposphere – the lowest layer of the atmosphere. It varies in thickness between 8km and 12km. it contains 75% of the atmospheric gases.

Urban heat island – the zone around and above an urban area which has higher temperatures than the surrounding rural area

Venturi effect – the squeezing of moving air through a narrow gap (between buildings) that increases the velocity of the winds

Warm front – a boundary between warm and cold air where warm air is advancing on cold air. The less dense warm air rises over the denser cold air. Fronts are associated with rainfall.

Weather – the hour-by-hour state of the atmosphere in any one place