Stormy weather Flashcards
Define Hazard risk
The degree of level of harm that will be caused by a natural hazard
Define natural hazard
A natural event that has the potential to cause harm
Economic impact
an impact which affects wealth of a place or sometimes income
Environmental impact
An impact that affects the natural world
Extreme weather
A weather event that is significantly different from the average weather pattern
What is the enhanced green house effect
the stronger impact caused by human emissions of green house gases
What is mitigation
A process which tries to reduce and prevent the effects of something from happening
What is adaption
The process of changing something that can become better suited to its use/ surrounding environment
Define weather
The state of the atmosphere at a particular place or time, including temperature, precipitation, humidity and wind speed
Define climate
the weather conditions prevailing in an area in general or over a long period
define insolation
the amount of solar radiation reaching a given area
define latitude
the angular distance of a place north or south of the earth’s equator, usually expressed in degrees or minutes
what factors affect a places climate
Land relief e.g above sea level, latitude, altitude
Distance from the sea
Distance from the equator
Aridity e.g lack of air moisture
Prevailing wind
Season
Why is the Earth’s atmosphere in constant motion
It is driven by the energy we receive from the sun. We get more energy in tropical areas near the equator and less at the poles. Air movements or winds help to balance this out
How does insolation vary considerably
Places at low latitude have higher levels of insolation as rays are spread over a smaller area (more concentration)
Places at higher latitude e.g poles have lower levels of insolation as the rays are spread over a greater distance/larger area
What is atmospheric pressure
the force by the weight of air above us
Explain convection currents
Warm air rises because it is less dense creating low pressure
Cool air sinks as it is more dense creating high pressure
What causes wind
air particles move from areas of high to areas of low pressure
Describe the global atmospheric circulation model
- air cools and sinks, creating a belt of high pressure and a cold, dry climate
- At about 60 degrees north and south cold polar air mixes with warmer air and rises, creating a blet of low pressure
- Cool air sinks creating a belt of high pressure, as it sinks it becomes warmer and dryer
- warmer air rises, it then cools. Clouds form then and release precipitation
- Above the air will eventually separate and move to higher latitudes
What is low pressure air
Rising air
Creates cold, wet climates
What is high pressure air
Sinking air
Creates warm, dry climates
Why does the equator receive higher levels of insolation
the solar energy strikes the ground at 90 degrees, so energy is concentrates on a small foot print causing eat metre squared to be heated strongly
Describe the Hadley cell
Taking the Hadley cell, warm air at the equator (0° of latitude) rises and then cools in the upper atmosphere, then circles back down towards the tropics (i.e. 30° of latitude).
Describe the ferrel cell
The air in the Ferrell cell moves in the opposite direction to the air in the Hadley cell with warm air moving toward the polar regions. The warm air that has travelled up from the equator converges with the cold air at 60° of latitude that has travelled down from the polar regions. As the air converges the warm air is forced to rise and move back towards the equator.
Describe the polar cell
The overall effect of the Polar cell is to move cold air towards the equator. At the poles (i.e. 90° of latitude) the cold air sinks. It then moves towards the equator. At 60° the combination of warm and cold air causes the warm air to rise, resulting in low air pressure at 60°. At 60° latitude the polar front is found. This is the result of the warm air that has travelled up from the equator and cold air from the poles being unable to mix well.
Describe how the cells are controlled
The Hadley and polar cell are controlled by the sun’s heat whilst the Ferrell cell is controlled by the movement of air in the other two cells
Describe precipitation at the Equator
The intense heating of the Earth’s surface near the equator causes warm, moist air to rise rapidly. As the air rises, it cools and condenses, forming clouds and eventually leading to precipitation. Rainfall is constant throughout the year at the equator
Describe precipitation at the intertropical convergence zone
Near the equator, the trade winds from the northern and southern hemispheres converge. This convergence zone is characterized by rising air, which promotes cloud formation and rainfall, even torrential rain.