Commercial - (Atmosphere, winds and clouds) Flashcards
(24 cards)
What are the layers of the atmosphere, and how are they defined?
The layers of the atmosphere are:
troposphere tropopause stratosphere stratopause mesosphere mesopause thermosphere
They are defined by altitude and by their specific characteristics at that level.
What makes up the atmosphere?
Nitrogen accounts for 78%, oxygen 21%, argon, carbon dioxide and other trace gases make up the remaining 1%.
What are the characteristics of the Troposphere?
Sea level to 20,000 feet over the northern and southern poles.
Up to 48,000 feet over the equatorial regions.
Contains vast majority of weather, clouds, storms, and temperature variances.
Lapse rate is 2°C every thousand feet of altitude gain.
Pressure decreases at a rate of 1 inch per thousand feet of altitude gain.
What are the characteristics of the tropopause?
Creates the boundary and the top layer of the troposphere.
Traps moisture and the associated weather in the troposphere.
Altitude varies with latitude and season of the year.
Has an elliptical shape.
Location is considered important because it’s associated with the location of the jetstream and possible clear air turbulence.
What are the characteristics of the stratosphere?
Extends from the tropopause to the height of about 160,000 feet.
Very little weather exists and the air is stable.
What are the characteristics of the stratopause?
Is the top layer of the stratosphere at approximately 160,000 feet.
What are the characteristics of the mesosphere?
Extends up to 280,000 feet
Temperature decreases rapidly with increasing altitude, can be as cold as -90°C
What are the characteristics of the mesopause?
Exists at approximately 280,000 feet and is the layer that separates the mesosphere from the thermosphere.
What are the characteristics of the thermosphere?
Starts above the mesosphere and gradually fades into outer space.
What is the jetstream?
A narrow band of wind with speeds of 100 to 200 mph usually associated with the tropopause.
At sea level the atmosphere exerts pressure on the earth at a force of?
14.7 pounds per square inch.
A column of air 1 square inch extending from the surface up to the upper atmosphere limit weighs about 14.7 pounds.
How does the human body experience the atmosphere pressure at sea level?
A force of pressure over the entire surface of the skin.
The actual pressure at a given place and time will differ with altitude, temperature, and density of the air, this causes what type of negative effect on airplanes?
Affects aircraft performance, especially with regard to take off, rate of climb, and landings.
The International Standard Atmosphere (ISA) represents what?
Provide a common reference for temperature and pressure 29.92 inches of mercury at 59°F or 15°C.
Also measured in approximately 34 millibars and standard sea level equalling 1013.2 millibars.
What can weather forecasters predict with movement of the pressure systems and the associated weather?
Rising pressure at a single WeatherStation indicates the approach of Fair weather, decreasing or rapidly falling pressure usually indicates approaching bad weather and possibly severe storms.
What are the effects of altitude on atmospheric pressure?
As altitude increases, pressure diminishes, as the weight of the air column decreases.
What effects will higher altitude have an aircraft?
Takeoff and landing distances are increased, climb rates are decreased.
What is the effect of differences in air density?
Differences in air density caused by changes in temperature result in changes in pressure. This creates motion vertically and horizontally in the form of currents and wind. When this motion combined with moisture it produces clouds and precipitation otherwise known as weather.
What are the two different kinds of motion in the atmosphere?
Vertical movement of ascending and descending currents and horizontal movement in the form of wind.
What is the cause of atmospheric circulation?
Atmospheric circulation is the movement of air around the surface of the earth. It is caused by uneven heating of the earths surface and upsets the equilibrium of the atmosphere, creating changes in the air movement and atmospheric pressure.
In general where do the low pressures and high pressures exist on earth?
Low pressures exist over the equatorial region and areas of high pressure exists over the polar regions due to a difference in temperature.
What causes the air around the equator to move towards the polar region and what causes the air around the polar region to move towards the equator?
Solar heating at the equator cause air to become less dense and rises in the equatorial areas. The resulting low-pressure allows the high-pressure air at the poles to flow along the planet surface toward the equator, this warm air flows towards the poles, it cools and becomes more dense and sinks back towards the surface. The rotation of the earth, Coriolis effect, impacts this direct high to low transfer of the pressure systems.
What is the Coriolis effect?
The Coriolis force is created by the rotation of the earth.
Describe Coriolis force in the northern hemisphere.
The Coriolis force deflects air to the right in the northern hemisphere causing it to follow a curved path instead of a Straight-line. The deflection differs depending on the latitude and is the greatest at the poles and diminishes to zero at the equator. In the northern hemisphere the rotation of the earth deflects moving air to the right and changes the general circulation pattern of the air.
