Global hazards Flashcards
1
Q
Natural Hazard
A
- An extreme natural event or process that can lead to loss of life and/ or damage to property and severely disrupts human activity
2
Q
What causes a tectonic hazard?
A
- The movement of the Earth
3
Q
What causes a Climate Hazard?
A
- Processes in the atmosphere
4
Q
Weather
A
- The day to day conditions of the atmosphere involving, for example, temperature, precipitation and wind
5
Q
Climate
A
- The average weather conditions recorded over a period of at least 30 years
6
Q
Atmosphere
A
- The air above our heads
- Mass of swirling gases, liquids and solids, such as CO2, O2, water vapour and droplets and ash
7
Q
Circulation
A
- Circular air movements called cells.
- These cells all join together to form the overall circulation of the Earth’s atmosphere
8
Q
What are the 3 circulation cells?
A
- Hadley Cell
- Ferrel Cell
- Polar Cell
9
Q
What is wind?
A
- The movement of air from an area of high to low pressure
- The greater the difference in pressure, the greater the winds
10
Q
Trade winds
A
- Winds that blow from high pressure belts to low pressure belts
- Used by trading ships to sail
- Mt. Washington has winds up to 372 km/hp
11
Q
Katabatic winds
A
- Caused by air flowing downhill
- In Antarctica, large sloping ice sheets contribute to wind speeds of over 320 km/h
12
Q
Jet stream
A
- Winds that are high in the atmosphere
- Speeds of 225 km/h recorded on Mr. Everest
13
Q
Tropical Storms
(winds)
A
- Very strong rotating winds
- Start smaller but develop into strongest winds ever recorded
- Die out when they reach land
- Highest speed recorded was 408km/h on Barrow Island in Hurricane Olivia in 1996
14
Q
The Albedo effect
A
- How much a surface reflects or absorbs the Sun’s rays
- The more reflective, the less heat it can hold
15
Q
What happens during El Niño?
(bullet points)
A
- Trade winds in the western Pacific Ocean weaken, stop or reverse
- The piled up water around Australia and Indonesia moves its way back towards the eastern Pacific Ocean
- Water in eastern Pacific Ocean gets 6-8 degrees warmer than usual
16
Q
What happens during El Niño?
(high pressure, low pressure etc.)
A
High pressure- Australia
Low Pressure- Peru
Rainfall- South America
Drought- Australia
Flooding- Peru
Trade winds- Weaken, stop or reverse
17
Q
What happens during a normal year?
(bullet points)
A
- Trade winds blow westwards over Pacific Ocean, pushing warm water from Peru to Australia
- In the eastern Pacific, off the coast of Peru, the thermocline is especially low