Weather Hazards Flashcards
How are Clouds and Rain formed?
- Sun warms at equator
- Transfer Heat to air, rises
- Creates low pressure belt
- As rises, cools & condenses = rain & clouds
How do you go to very low rainfall from clouds and rain?
- 30 degrees N & S of equator
* Cool air sinks = high pressure belt = cloudless skies & very low rainfall
How does Winds transfer Heat from the Equator to the Poles?
- Winds blow from areas of high to low pressure transferring heat away from equator
- Loops in winds have warm rising air creating low pressure belt, & at poles cool falling air creating high pressure belt
What are the Cells in each Hemisphere
- Hadley
- Ferrel
- Polar
How is Heat transferred by Ocean Currents?
Have large scale movements of water that transfer heat energy from warmer to cooler regions
How are Surface Currents caused and what do they do?
- By winds
* Help transfer heat away from equator
What are Deep Ocean Currents driven by and what do they do?
- Differences in water density
* Freezes = more dense = sinks = warmer water flow in at surface = current
What does Global Atmospheric Circulation cause?
•Pressure belts - cause variation in climate
Describe the Temperature of Low Pressure belts and where is it located?
- Low pressure belt at 60 degrees N/S from rising air = rainfall
- Between tropics & poles, temp zones have moderate summers & winters
What is the Polar climate and how is it made?
- Sinking air from Polar Cells = high pressure at poles
* Temp low all year, little rainfall
What is the Tropical Climate and how is it made?
- Rising air from Hadley Cells meeting = low pressure
* Hot temp all time, high rainfall
What is the Arid(dry) climate and how is it made?
- Sinking air from Hadley & ferrel Cells meeting = high pressure
- Low rainfall for most of year, hot temperature
When does Precipitation occur and where is it Frequent?
- Warm,wet air rises & cools, cause water vapour to condense
- Low pressure - frequent
- High pressure - very low
When do Tropical Storms occur?
- Sea temp 27 degrees or higher
* Wind shear between high & low parts of atmosphere is low
How does Surface Winds Increase?
- Warm, moist air rises & condensation occurs
- Release huge amount of energy = more powerful storms
- Rising air = area of low pressure
- Increasing surface winds
Where do Tropical Storms move?
Towards west because of easterly winds near equator
Why do Storms spin?
Earths rotation deflects paths of winds
Where and Why does Storms Loose Strength?
- Move over land or cooler water
* Energy supply from warm water is cut off
Where and When do most of Storms Occur?
- Northern hemisphere (over pacific)
* In late summer/autumn when sea temp is highest
What is the Motion of Tropical Storms?
- Northern hemisphere - spin anticlockwise
* Southern hemisphere - spin clockwise