Geography Topic 2 - Weather Hazards and Climate Change (Summer Y9/ Autumn Y10)

flashcards done up to Tropical Cyclones

What are the 3 circulation cells

Hadley, Polar, Ferrel

Hadley Cell

• 0-30 degrees latitude

• warm ascending air near the equator and descending air around 30 degrees latitude.

Ferrel Cell

• 30- 60 degrees latitude

• Rising air causing low pressure

Polar Cell

• 60-90 degrees latitude

• Sinking Air creates high pressure at the poles

Low pressure means…

• hot air rises

• unstable

• stormy, cloudy weather

High pressure means…

• cold air sinks

• stable

• clear, calm weather

Coriolis effect

Winds blow from high to low pressure, and Earth's rotation deflects them right (Northern Hemisphere) and left (Southern Hemisphere).

Ocean Currents

They transfer tropical heat energy from the equator toward the polar regions, helping to regulate global climates

Quarternary Period

last 2.6 million years

Climate Change in the Quarternary Period

• Glacial Epochs> cold periods, 100,000 years long, ice sheets advance over large parts of the globe

• Interglacial Epoch> warm periods in between glacial epochs, 10,000-15,000 years, we are currently in one

Natural Causes of Climate Change

• Milankovitch Cycles

• Solar Output

• Volcanic Activity

Milankovitch Cycles

• Eccentricity (changes in earth’s orbit)

• Obliquity (axial tilt)

• Precession (wobble)

Solar Output

Fluctuates with sunspots: high sunspot activity increases global temperatures

Volcanic Activity

Ash Clouds and Sulfur Dioxide block sunlight causing short term global cooling

Evidence for Climate Change

• Ice Cores

• Pollen Data

• Tree Rings

• Proxy Data (old diaries/ paintings)

Human Causes of Climate Change

• Burning Fossil Fuels (CO₂)

• Transport (CO₂)

• Deforestation

• Livestock farming (CH₄ = Methane)

Greenhouse Effect

1. Sun gives off ultra violet energy

2. The Earth absorbs the energy

3. Re radiated as Infra Red energy

4. Greenhouse gases absorb infra red energy which raises air temperature

Negative Impacts of Climate Change

• Sea Level Rise

• Retreating Glaciers

• Extreme Weather Frequency

• Changing Crop Yields

why does the UK have a TEMPERATE climate

• It is located 50-60 degrees latitude which means we receive less concentrated solar heating than the equator but more than the Poles

Why does the UK have a WET climate

We are located in the Polar Front between the Ferrel and Polar cells so warm air rises and condenses causing Frontal Rain.

why does the UK have a MARITIME climate

• It is an Island surrounded by the Atlantic Ocean

• North Atlantic Drift > warm ocean current

• Prevailing South-Westerly Winds

UK climate over the last 1000 years

• Medieval Warm Period: 950-1250 AD

• Little Ice Age : 1400-1850 AD

Conditions for Tropical Cyclone Formation

• Sea temperature over 27 degrees celcius

• 60 metres deep

• low air pressure

• In between the tropics

Tropical Cyclone Formation Sequence

1. Warm air over the sea rapidly rises creating an intense area of low air pressure at the surface

2. Rising air cools and condenses, releasing latent heat which warms the air further

3. Coriolis Force spins the rising air

4. Storm loses power over land/cooler water

Structure of a Tropical Cyclone

• The eye : Central zone with light wind and clear skies

• The eyewall: strongest winds and heaviest rainfall

What are tropical cyclones called in different areas

• Hurricanes in America

• Typhoons in the Asian Pacific

what are tropical cyclones measured with

The Saffir Simpson Scale (1-5)

Hazards caused by Cyclones

• High Winds (over 120 km/h)

• Intense rainfall

• Storm Surge (Catastrophic Coastal Flooding) most dangerous

• Landslides (de-stablised soil on steep slopes)

When and Where did Hurricane sandy start

24th October 2012 in the Carribean Sea where it travelled North

ECONOMIC Impacts of Hurricane Sandy on Cuba vs USA

• damaged 15,000 homes in Cuba and 100,000 homes in the US

• Coffee and Banana Plantations Destroyed in Cuba

• Airports and Hotels damaged in Cuba which meant less tourism

• New York Stock Exchange shut down in US

• Total loss in Cuba was 2 billion dollars (5% GDP)

• Total Loss in US was 19 billion dollars (0.1% GDP)

SOCIAL Impacts of Hurricane S on Cuba vs USA

• 11 people killed by collapsing buildings in Cuba, 117 killed by storm surge in USA

• 430,000 without electricty and water, 9 million without electricity for 2 days

• Subway system closed in New York

ENVIRONMENTAL Impact of Hurricane S on Cuba vs USA

• beaches eroded and most trees knocked down in Santiago de Cuba, New Jersey Beaches eroded

• Many landslides in Cuba destroying plantations

• Raw sewage released into rivers in USA