Weather Hazards and tropical storms

what is global atmospheric circulation?

The transfer of heat from the equator to the poles by the movement of air

why does are move and where does it move to?

-due to differences in pressure

- from areas of high pressure to low pressure

what type of pressure is formed when air rises?

low

what type of pressure is formed when air sinks?

high

global atmospheric circulation system: ALL STEPS

- sun warms earth at the equator

- this causes air to rise

- creating a low pressure belt

- as the air rises it cools and moves away from the equator

- at 30 N and S, the cool air sinks forming a high pressure belt

- once it reaches the ground, the cool air either travels back to the equator as trade winds or to the poles as westerlies

- these winds are curved due to the coriolis effect

- at 60 N and S, the warm winds meet colder air from the poles

- the warmer air rises creating low pressure

- some travels back to the equator and the rest travels to the poles

- once it reaches the poles, cool air sinks, forming an area of high pressure

- it then travels back to the equator

how is the UK's climate influenced by the global atmospheric circulation system

- it lies close to the low pressure zone at 60 N

- here, warm air rises which brings lots of cloud cover and rainfall as it condenses

- this often is in the form of low pressure systems carried from the Atlantic by westerly winds

how are desert climates created by the global atmospheric circulation system?

- by the time the air reaches 30 N and S, it has released most of its moisture as rain

- dry air means there are few clouds and little rainfall so deserts are often found at this latitude

how does the global atmospheric ciruclation system affect the climate of rainforests?

- at the equator the suns rays are the most concentraded so the earth's surface receives the most solar radiation and is hot

- warm moist air rises to form clouds, so it rains a lot

explain how a tropical storm forms

- they form over oceans or seas with temperatures over 27 degrees

- seawater evaporates and the warm moist air rises creating a low pressure area below

- the air cools and condenses, releasing latent heat which forms storm clouds and precipitation

- a low wind shear means that the storm develops vertically with no disruption from varying wind speeds at different altitudes

- the earth's rotation causes the coriolis effect, so the rising air rotates, forming a spiral shape.

- 70m deep water supplies heat and moisture, maintaining its energy

- as the storm intensifies, air spirals upwards and outwards forming bands of clouds

- at the centre, an eye forms which is a calm, clear area

- it is surrounded by the eye wall- the most intense part with the highest wind speeds and heaviest rainfall

- winds are drawn into the centre and influenced by trade winds which sustains the rotation and intenstiy.

Key features of a tropical storm

eye

eyewall

Eye of a tropical storm

- centre of a tropical storm which is 50km across and caused by descending air

- calm air, high temperature, light winds, no rain, no cloud

eye wall of a tropical storm

- most intense part- strongest winds, heaviest/torrential rain, low temperature, lost of clouds, spiralling rising air

outer parts of a tropical storm

- decrease in wind speed, higher temperature, clouds smaller and more scattered, less intense rain

which way do tropical storms spin in each hemisphere?

northern= anti clockwise

southern= clockwise

how will climate change make tropical storms more severe?

- frequency

- distribution

- intensity

how does climate change affect frequency of tropical storms?

- increased temps

- so oceans will be at temperature > 27 degrees for longer periods of time per year

- meaning more storms will form each year

how does climate change affect the distribution of tropical storms?

- average ocean temperature rises

- more of the world's oceans will have temperatures greater than 27 degrees

- so they will happen in a greater range of places and areas that haven't yet experienced tropical storms, e.g higher latitudes

how does climate change affect the intensity of tropical storms?

- higher sea surface temperature

- more evaporation

- more cloud formation

- more energy released

- more powerful storms

how to reduce the effects of tropical storms

- planning

- prediction

- protection

how can planning reduce the effects of tropical storms?

- emergency services training

- future developments should avoid high risk areas

- government can plan evacuation routes

how can prediction reduce the effects of tropical storms?

- satellites, radars and aircrafts can monitor storms

- computer models can be used to calculate the predicted path of a storm

- gives people time to evacuate

how can protection reduce the effects of tropical storms?

- designing buildings to withstand storms

- building a house on stilts to defend against floodwater

- build defences like levees or sea walls

how is the UK's weather becoming more extreme?

- temperature

- rainfall

evidence that temperature in the UK is becoming more extreme

- 10 warmest years have all occured since 2002

- 2018 was the joint hottest summer on record

- 11 coldest recorded temperatures were since 1980

- december 2010- coldest month for >100 years

evidence that the UK's rainfall is becoming more extreme

- more rainfall records broken between 2010-2014 than in any decade on record

- more frequent flooding events in the past 10 years

- december 2015- wettest month ever