150 likes | 276 Views
Weather systems in mid-latitudes and their interaction with human environments. Frontal depressions and associated weather. Polar Front : occurs when Tm meets Pm, it is along this front that depressions form. Stage 1 : Embryo Depression Waves form due to friction between 2 air masses
E N D
Weather systems in mid-latitudes and their interaction with human environments Frontal depressions and associated weather
Polar Front: occurs when Tm meets Pm, it is along this front that depressions form
Stage 1 : Embryo Depression Waves form due to friction between 2 air masses Warm air bulges into cold air As air rises it spirals anticlockwise The greater the diff bet the warm & cold air masses, the stronger a depression develops Move NE due to upper westerlies (PFJS) Life Cycle of a Depression Pm Tm
Stage 2 : Mature Depression • increased amplitude of wave • -pressure continues to fall as warms • sector is forced to rise • -pressure gradient steepens • wind strength increases • rising air cools to dew point, large amount • of latent heat released • -clouds form, precipitation falls • Warm front – band of rain up to 150km wide • Cold front – greater intensity & shorter • duration of rain (band only 10-50km wide) – • Max wind strength due to greater temp • difference
Stage 3 : Decay Depression • -Cold front catches up the warm front to • form an occlusion or occluded front • No warm sector left at ground level • Less uplift – less condensation – less • latent heat – less ppt – less cloud – • pressure rises – winds decrease • -Colder air replaces the uplifted air and • ‘infills’ the depression
High clouds : Ci – cirrus, Cc – cirrocumulus, Cs – Cirrostratus, Cb – Cumulo-nimbusMiddle clouds : Ac – altocumulus, As – altostratus, Cu – cumulusLow cloud : St – stratus, Ns – nimbostratus, Sc - stratocumulus CLOUD ASSOCIATED WITH A DEPRESSION
Explain how and why weather conditions have changed. Why is O now 5 degrees warmer? How would weather conditions have affected activities on the ground over these tow days? Describe weather conditions at O & S.Explain why the weather is like this, think about - time, air pressure.
‘The Great Storm’ 16 Oct 1987, read page 232-233 of text book plus handout materials. Make a list of the causes of the storm and the effects of the storm. Complete the noting activities on the second page of handout.
Complete Q,15, 16, 17, 18 on page 258 of your text book. Make sure you have enough detail to cover the marks allocated.
Tasks on depressions: • 1. Complete Q,15, 16, 17, 18 on page 258 of your text book. Make sure you have enough detail to cover the marks allocated. • 2. This task is very important, it looks at the effect that depressions have on peoples lives: • ‘The Great Storm’ 16 Oct 1987, read page 232-233 of text book plus handout materials. Make a list of the causes of the storm and the effects of the storm. Complete the noting activities on the second page of handout. • 3. Make a list of all the ways that a typical depression could affect people’s lives