Meteorology Flashcards
Atmosphere
This is a mix of life-giving gases surrounding our planet
Atmosphere
If you could capture 1 cubic foot, what would the atmosphere compose of based from that measur?
- 78% Nitrogen
- 21% Oxygen
- 1% other several gases, primarily argon and carbon dioxide
This is a standard against which to compare the actual atmosphere at any point and time. This is used to calculate instrument and aircraft performance, among others
- International Standard Atmosphere (ICAO)
What is the standard density?
1.225 kg/m³
What is the standard pressure lapse rate?
1 inHg/ 1000ft
What is the standard temperature lapse rate?
1.98 °C / 1,000ft
This is extending from the surface to an average altitude of 36,000 feet
Troposphere
This acts as a lid to confine most of the water vapor, weather
Troposphere
This extends to an altitude of approximately 160,000 feet and it has much the same composition as the troposphere
Stratosphere
It may be simply considered to be the movement of air relative to the earth’s surface
Atmosphere Circulation
What are the three cell convection
- Hadley Cell
- Ferrel Cell
- Polar Cell
This is named after an 18th century scientist who first proposed the model of general circulation. This forms between O° and 30°
Hadley Cell
This is named after another researcher of general circulation, forms between 30° and 60°
Ferrel Cell
This exists between 60° and the poles
Polar Cell
The unequal heating of the surface of the earth not only changes air density and created circulation patterns, it also causes changes in __________
pressure
Where do meteorologists plot these pressure readings on weather maps and connect points of equal pressure with lines?
Isobars
What does the resulting patterns in isobars reveal?
Pressure gradient
What does it mean when isobars are spread widely apart?
It is considered to be weak
What does it mean when isobars are closely spaced?
Strong gradient
What pressure systems do isobars help identify?
- Highs
- Lows
- Troughs
- Ridges
- Cols
This is a center of high pressure surrounded by lower pressure
High
This is a center of low pressure surrounded by higher pressure
Low
This is an elongated area of high pressure
Ridge
This is an elongated area of low pressure
Trough
This can designate either a neutral area between 2 highs and two lows, or the intersection of a ridge and trough
Col
The force behind the movement of air is caused by the pressure gradient and is called?
Pressure Gradient force
A strong gradient tends to produce? While a weak gradient results in?
Strong winds, lighter winds
This affects all objects moving freely across the face of the earth such as: ocean currents,airplane flight paths, which would otherwise follow a straight line, end up tracing a curved path to the earth’s rotation
Coriolis force
In the northern hemisphere, any deviations will go where of its intended path?
To the right
In the southern hemisphere, any deviations will go where of its intended path?
To the left
What works in combination to create wind?
Pressure Gradient and coriolis force
This causes the air to move from high pressure to low pressure
Pressure Gradient force
In which direction does a high pressure area flow? and for low pressure area?
Clockwise (high), Counter- Clockwise (low)
This is a low pressure system of the atmosphere in which air pressure has dropped below the standard (normal) atmospheric pressure
Cyclone
In which direction do winds rotate in the northern hemisphere?
Inward in a counter-clockwise direction
In which direction do winds rotate in the southern hemisphere?
Clockwise direction
This reduces Coriolis Force and is caused by the earth’s surface which in turn slows the moving air
Frictional Force
This low-level southerly flow is deflected to the West creating the..?
North East Trade Winds
The low-level air flowing northward from the High Pressure area at 30 ° is also deflected to the right
Westerlies
The cold polar air which flows southward from an area of High Pressure is deflected to the right to create the…?
Polar Easterlies
These are narrow bands of strong wind in the upper levels of the atmosphere. They follow the boundaries between hot and cold air
Jet Streams
True or False. The air over the equator will be moving toward one of the poles and will keep its eastward motion but the earth below the air, moves slower as that air travels toward the poles
True
Temperature changes are the greatest in which areas?
30° North and South and 50° - 60° North and South
As the difference in temperature increases between the two locations, the strength of the wind _______?
Increases
They are often indicated by a line on a weather map indicating the location of the strongest wind.
Jet streams
This is a belt of Low Pressure which circles the Earth generally near the equator where the trade winds of the northern and southern hemisphere come together
Inter-tropical Convergence Zone (ITCZ)
This is characterized by convective activity which generates often vigorous thunderstorms.
Inter-Tropical Convergence Zone (ITCZ)
Where the trade winds are weaker, the ITCZ is characterized by what?
Isolated Cumulus and Cumulonimbus clouds
Where the trade winds are stronger, the ITCZ can spawn what?
A strong line of active cumulonimbus clouds with other cloud types developing as a result of instability at higher levels
These are caused by terrain variations such as mountains, valleys, and water
Local Wind Patterns
The force behind the local wind patterns are _____________ replacing ___________ - a smaller scale of global wind patterns
cool air, warm air
During the day, the land surface heats up faster than the water surface, as the warm air over the land is rising, the cooler air over the ocean is flowing over the land surface to replace the rising warm air
Sea Breeze
True or false. The land surface cools quicker than the water surface at night
True
As mountain slopes are warmed by the sun, the adjacent air is also heated. Since the heated air is less dense than the air at the same altitude over the valley, an “upslope flow” known as the ________
Valley Breeze
At low levels, the air typically flows up the valley and up the warm slopes during the day, this is also called _____
Anabatic Winds
At night, the higher terrain cools off and eventually becomes cooler than the air over the valley. The pressure gradient is reversed, causing a ‘‘downslope flow’’ or …?
Mountain Breeze
What is another term for mountain breeze?
Katabatic Winds
When large ice and snow fields accumulate in mountainous terrain, the overlying air becomes extremely cold and a shallow dome of High pressure forms which pushes the cold air through gaps in the mountains, and as the air may be warmed during descent, it’s still colder than the air it displaces
Cold Downslope Winds
When a warm air moves across a mountain range at high levels, it often forms a trough of low pressure on downwind side which causes a downslope wind and as the air descends, it is compressed which increases the temperature
Warm Downslope Winds
It is the atmosphere’s resistance to vertical motion
Atmospheric Stability
When air moves downward, it is compressed by the increased pressure at lower altitudes. As pressure of a given portion of air changes, so does its temperature and when air descends, pressure increases, volume decreases, and temperature increases
Adiabatic Heating
When air moves upward, it is expanded by the decreased pressure at higher altitude. As pressure of a given portion of air changes, so does its temperature and when air rises, pressure decreases, volume increases, and temperature decreases
Adiabatic Cooling
This happens when temperature increases with altitude. This develops when cool air is trapped at the ground under a layer of warm air
Temperature Inversions
Change of liquid water to water vapor. As water vapor forms, heat is absorbed from the nearest available source
Evaporation
This occurs when water vapor changes back to liquid. This is just like how water droplets form on a cold grass of water on a warm day.
Condensation
The process in which a solid changes directly to a gas is called? It occurs when the particles of a solid overcome the intermediate liquid stage and directly reverts back to a gas state
Sublimation
This is the process in which a gas changes through the liquid state. It occurs when gas particles become very cold
Deposition
It is basically water vapor and is responsible for many of the flight hazards encountered in aviation operations
Moisture
This simply refers to the amount of moisture in the air
Humidity
This is the amount of moisture in the air compared to the total amount that could be present at that temperature
Relative Humidity
This is an absolute measure of ‘‘how much’’ moisture is in the air. It is the temperature at which the air reaches a state that it can no longer hold more water (moisture)
Dewpoint
When lifted, unsaturated air cools at about what height and temp?
5.4° F per 1,000 feet
Dew point temperature decreases at about what temp per height?
1° F per 1,000 feet
temperature and dew point converge at what temp and height?
4.4° F per 1,000 feet
