Weather Flashcards
What is the atmosphere?
The atmosphere is a mixture of gases that surrounds the earth. It provides us with air to breathe, it acts as a shield to protect us from the sun’s UV rays, it regulates the earth’s temperature, etc.
How is the atmosphere composed?
The atmosphere is composed of several gases but mostly nitrogen and oxygen.
Nitrogen 78%
Oxygen 21%
Trace gases 1%
What happens to the warm air and cold air in the atmosphere in relation to it’s motion?
Hot air rises and cool air takes over.
What is the Coriolis effect?
The Coriolis effect is the phenomenon that causes fluids like water or air to curve as they travel across or above the Earth’s surface.
How do High and Low pressure areas act in the Northern Hemisphere?
In the northern hemisphere the high pressure areas rotate clockwise as it sinks and the low pressure areas rotate counterclockwise as it rises.
How are high pressure and low pressure areas associated?
High pressure areas are associated with:
- Light winds
- Good weather
- Stable air
- Clear skies
Low pressure areas in the other hand are associated with:
- Cloudy skies
- Unstable air
- Precipitation
- Strong winds
What is a front?
A front is a boundary where two different air masses meet. These air masses have different temperatures and humidity levels. When they come together, they can cause changes in the weather, such as rain, clouds, or changes in temperature.
What are the 4 types of fronts?
- Cold front
- Warm front
- Stationary front
- Occluded front
Explain a warm front
A warm front occurs when a warm air mass advances and replaces a colder air mass, covering the cold air mass from the top and forcing it out and below. This type of front moves relatively slowly, about 10-15 mph.
Explain a cold front
Cold fronts occur when a cold air mass advances and pushes under a warmer air mass forcing the warm air mass to rise. During cold fronts it is very common to expect precipitation, cloudy skies and often thunderstorms. Cold fronts move faster than warm fronts, typically about 25-30 mph.
Explain stationary fronts
A stationary front occurs when two air masses, one warm and one cold, meet but neither is strong enough to replace the other. This results in the front remaining in place for an extended period. Stationary fronts often bring prolonged and steady precipitation that could last for hours or days.
Explain occluded fronts
An occluded front occurs when a cold front catches up with a warm front, lifting the warm air mass off the ground being trapped between two cooler air masses.
There are two types of occluded front:
- Warm occlusion
- Cold occlusion
What is a squall line?
A squall line is a line of thunderstorms that form ahead of a cold front.
What is dewpoint?
The dew point is the temperature at which the air becomes saturated.
What is pressure altitude?
Pressure altitude is true altitude corrected for non standard pressure.
What is density altitude?
Density altitude is pressure altitude corrected for non standard temperature.
What is fog?
Fog is a low level cloud of tiny water droplets suspended in the air near the ground. It’s the result of the air near the surface to cool to it’s dewpoint and condense.
When does fog usually form?
Fog forms when air near the surface cools to it’s dew point, which causes water vapor to condense.
What are the different types of fog?
- Upslope fog
- Steam fog
- Precipitation fog
- Advection fog
- Ice fog
- Radiation fog
What are some weather phenomenons that occur when air becomes saturated?
- Dew
- Frost
- Fog
- Clouds
- Rain
- Snow
What is a thunderstorm and what are the three ingredients of a thunderstorm?
A thunderstorm is a weather event that involves lightning, thunder, heavy rain, and often strong winds. The three ingredients of a thunderstorm are:
- Lifting action
- Unstable atmosphere
- Moisture
How do thunderstorms create?
Thunderstorms forms when warm moist air rises, as the warm air rises, it cools and the moisture in it condenses into water droplets, creating clouds. As more warm moist air rises, the cloud grows vertically turning into a cumulonimbus cloud. Inside the cumulonimbus cloud all air, water and ice particles bum into each other creating electric charges.
What is windshear?
Wind shear is a sudden change in wind speed and direction over a short distance, it can occur either horizontally or vertically.
What is turbulence?
Turbulence is a sudden change in air flow that causes the airplane to change it’s attitude, altitude and direction.
What are four different types of turbulence?
- Thermal turbulence
- Wake turbulence
- Mechanical turbulence
- Clear turbulence
What are the three types of aircraft structural icing?
- Clear Ice
- Rime Ice
- Mixed Ice
Explain clear ice
Clear ice happens when supercooled water dropplets freeze slowly upon contact with the aicraft’s surface, creating a clear layer of ice.
Explain rime ice
Rime ice forms when supercooled water droplets freeze rapidly upon contact with the aircraft, creating a rough, white, and opaque layer of ice.