Climate Flashcards
(37 cards)
What factors affect temperature?
Latitude - countries nearer the equator are warmer as the sun is concentrated here.
Distance from the sea - the sea takes longer to heat up than the land. In summer, the land heats quickly while the sea heats slowly. This means that places near the sea are kept slightly cooler than inland. The opposite happens in the winter as the sea takes longer to cool down.
Ocean currents - the gulf stream is a current of warm water that crosses the Atlantic Ocean from the Gulf of Mexico, and warms the west coast of the UK.
Prevailing winds - in the N hemisphere, wind from the north will bring cooler temperatures as they have come from the north pole. If winds blow over dry lands they will dry out, but if they blow over the sea they will bring rain.
Altitude - the temperature falls by one degrees for every 100m incline.
What is convectional rainfall?
When the sun heats an area of water on the ground. This leads to evaporation, then condensation. This leads to cloud formation and rainfall.
What is relief rainfall?
When air approaches a mountain it is forced to rise, it then condenses forming clouds. You often get a rain shadow on the other side of the mountains (leeward side) where little rain falls.
What is frontal rainfall?
Occurs when warm air collides with cold air. The two air masses have different densities and do not mix. This means that the light warm air rises up and over the denser cold air. The warm air rises, cools, condenses and forms rain.
What is an air mass?
A large body of air with similar temperature or humidity throughout its layers.
What is the artic maritime air mass?
Brings very cold conditions in winter. Snow is common.
What is the polar continental air mass?
Brings very cold and dry conditions in winter and settled hot conditions in the summer.
What is the tropical continental air mass?
Brings hot and dry conditions. It can bring sand and dust from Africa on the southerly winds.
What is the tropical maritime air mass?
Brings mild conditions in winter and warm conditions in the summer with frequent periods of rain. This is a very common air mass affecting the UK throughout the year.
What is the polar maritime air mass?
Brings cool conditions in summer and cold conditions in the winter with longer periods of rain or snow. This mostly affects the UK in the winter.
What conditions do high pressure anticyclones bring?
Clear skies
Very cold in winter or very hot in summer
No clouds
Light winds.
What is a low pressure depression?
They happen when a wedge of warm air forces itself into cold air, creating two fronts. The warm front is followed by the cold front. Depressions are low pressure systems associated with wind and two bands of rain. They spin in an anti-clockwise direction and are associated with rising air or low pressure.
What is the Hadley cell?
Global air circulation.
Air on the equator is heated which causes it to rise. Rising air cools and condenses to form rain clouds. This is called convectional rainfall and creates an area of low pressure. This is why you get tropical rainforests on the equator.
Air that has risen above the Equator, cools and sinks back down over the Tropics of Cancer and Capricorn. Sinking air means high pressure and dry weather. This is why deserts are found over the Tropics of Cancer and Capricorn.
This circulation of air between the Equator and the Tropics is called the Hadley Cell.
What is the Ferrel Cell?
It marks the point on the planet where warm and cold air meet. The UK sits on this cell. Where warm and cold air meet you get depressions forming (low pressure and wet weather).
What is the Polar Cell?
The polar cell sits over the north and south pole. Air is cold and for this reason heavy and sinking. Sinking air creates high pressure and dry and very, very cold weather.
Define weather
Describes the day to day conditions of the atmosphere. Weather can change quickly. One day it can be dry and sunny the next day it may rain.
Define climate.
Describes average weather conditions over longer periods and over large areas.
What does temperate mean?
No temperature extremes like the intense heat in the tropics or the intense cold near the poles.
What does maritime mean?
The UK is surrounded by the ocean so the sea has a a large influence on the temperature and rainfall.
How does latitude effect weather?
Places at lower latitudes near the equator are much warmer than places at higher latitudes nearer to the poles. This is because the suns rays are more concentrated nearer to the equator making it warmer. The rays are more spread out over the curved surface of the Earth making it cooler. The S is a lower latitude than the N of the UK.
How does distance from the sea effect the weather?
The sea takes longer to heat up than the land. In summer, land heats quickly while the sea heats up slowly. Places next to the sea are therefore kept slightly cooler than places further in land.
In winter, the sea takes longer to cool down than the land, meaning places near the sea are kept a bit warmer in winter whilst places in land get very cold.
How do prevailing winds effect weather?
The direction the wind blows most often. In the N hemisphere, winds from the North will bring cooler temperatures as they have come from near the N pole. Winds from the S originate from near the equator and bring warm temperatures. If winds blow over land they will be dry, but if they blow over land they will pick up lots of moisture and bring rain.
Britain’s prevailing wind blows from the SW over the warm Atlantic Ocean.
How do Ocean Currents effect weather?
The Gulf Stream is a current of warm water which crosses the Atlantic Ocean from the Gulf of Mexico and warms the W coast of the UK. Ths is why it is warmer in the UK in Winter than many places which are on the same latitude.
How does altitude effect the weather?
The higher you go above sea level, the cooler it gets. The temperature usually falls by 1 degree Celsius for every 100m gained. This is because the air is less dense in higher altitudes, so it isn’t as good at holding heat.
