Level 5 What are the reasons for British Weather and Climate? • We will learn about:- • Low Pressure (Depression) weather • High pressure (Anticyclone) weather Low Pressure over Britain High Pressure over North Africa
What weather do we get when air pressure is high (Anticyclone)? Cut and paste these answers into the spaces.. Blanket fog sinks anticyclones We get ____________ (high air pressure) when air ___ down from above, giving clear skies. • In a British summer anticyclones cause fine, sunny days. At night the earth does not have a ______ _ of cloud, so the air gets colder, causing mists which last till morning. • British winter nights get very cold in anticyclones, causing frost and sometimes ____ which can last all day. North Atlantic Ocean Europe High Pressure over North Africa
High Pressure (Anticyclones)Study this diagram. Then pencil it into your book from memory. Then check and correct it. Jet streams of air move together 10 000 metres above the earth so air is forced to sink downwards. Sinking air creates clear skies. Clear skies mean sunny days but cold nights as there is no blanket of cloud to keep the earth’s heat in. High Pressure gives sinking air. Sinking air gives clear skies. Anticyclone air spirals out clockwise at the surface
What weather do you think North Africa is having? • Over North Africa there are no ______ so it is likely that there is High Pressure. • High Pressure gives ______, calm days. • High pressure gives ____ nights as there are no clouds to keep in the earth’s ____. • Sunny Cold Heat Clouds There is no cloud over North Africa because it has High air pressure on this day.
Review • Now write a paragraph here to describe and explain the weather associated with an anticyclone in winter.
What are Depressions (Low Pressure) like? They are windy, cloudy and rainy. Along the line of the fronts there is rain. At the blue triangles there is heavy rain and maybe hail. At the red semi-circles the rain is lighter. Depressions bring wind, cloud and rain to UK.. CENTRE OF LOW PRESSURE Warm Front (COLD AIR) Cold Front (WARM AIR) Heavy rain Warm Air Light rain
What sort of Weather is the depression bringing to Great Britain? • As you see the UK is covered with ______. • There is heavy _______in western England and Scotland. • There is ______ rain in Eastern England and Scotland. • Now cut and paste your answers • Rain Light Cloud Great Britain
Review • Look at web site http://ww2010.atmos.uiuc.edu/(Gh)/wwhlpr/warm_front • It shows good animations for warm and cold fronts. • Now write a paragraph to describe what happens to warm air when it meets cold air at a warm front.