Meteorology Flashcards
What is the chemical composition of the earth’s atmosphere?
78% nitrogen
21% oxygen
1% CO2, inert gases
Water vapour
Impurities
Describe the different atmospheric layers in terms of altitude and temperature
What are the vital characteristics of the atmopshere?
Mobility, capacity for expansion, capacity for compression
List the characteristics of the ICAO standard atmosphere
15°C at sea level
Lapse rate of 1.98 degrees / 1000’
29.92” mercury
No humidity
Describe the atmospheric mass below certain altutides
What are two sources of temperature change?
Diurnal and seasonal
Where is the atmosphere heated from?
from below
Describe air in terms of conductivity and ability to absorb radiation
Air is a very poor conductor yet will readily absorb radiated heat
What is advection?
The horizontal transport of an atmospheric variable (like heat) due to mass motion by the wind
How does temperature affect the density of air?
Air expands when it is cool, and compresses when it is warm
List and describe three different ways humidity can be quantified
Relative humidity - how much water vapor is in the air, compared to how much it could hold at that temperature
Absolute humidity - measure of water vapor in the air, regardless of temperature
Temperature/dewpoint spread - the number of degrees of difference between the air temperature and the dew point
What is the dew point?
the temperature (in degrees) to which air must be cooled in order to be saturated with water vapor already in the air
Describe the state changes of water
At what humidity do clouds form? How can a parcel of air reach this humidity?
100% humidity
A parcel of air can become 100% humid by adding water and decreasing temperature
What are the following lapse rates:
Environmental
Dry adiabatic
Saturated Adiabatic
Environmental: 1.98°C/1000’
Dry adiabatic: 3°C/1000’
Saturated adiabatic: 1.5°C/1000’
List the altitude ranges for high, medium, and low clouds
High: 20,000’ - 40,000’
Medium: 6500’ - 20,000’
Low: ground - 6500’
Categorize the following clouds into low, middle, and high clouds. Which ones have vertical development?
altocrumulus, altostratus, cirrocumulus, cirrostratus, stratus, stratocumulus, nimbostratus, cumulonimbus, cirrus, cumulus
What kind of cloud is this?
Cirrus
What kind of cloud is this?
Cirrostratus
What kind of cloud is this?
Cirrocumulus
What kind of cloud is this?
Altostratus
What kind of cloud is this?
Altocumulus
What kind of cloud is this?
Cumulus
What kind of cloud is this?
Cumulonimbus
What kind of cloud is this?
Lens clouds
What kind of cloud is this?
Cap cloud
Describe orographic lifting. Where do clouds and precipitation form?
Describe how convective lifting forms a cumulus cloud
Describe how fronts form clouds
Describe the turbulence lifting agent
Air blowing on uneven surfaces causes uneven heating, which allows vertical currents to occur. Air moves upward, expands, and cools
Describe the convergence lifting agent
Air piles up over a region of low pressure. Excess air is forced to rise, expand, and cool
Describe cloud cover in oktas
Clear - no clouds
Few - 2 oktas
Scattered - 3 to 4 oktas
Broken - 5 to 7 oktas
Overcast - 8 oktas
How much does atmospheric pressure decrease with every 1000’?
one inch of mercury
How much in error will your altimeter be if you park the plane overnight and the pressure drops .10” of mercury?
100”
Define the following:
Indicated altitude, true altitude, absolute altitude, pressure altitude, density altitude
Indicated altitude: what the dial says
True altitude: actual height above sea level
Absolute altitude: actual height above ground
Pressure altitude: what your altimeter would read if set to 29.92”
Density altitude: a theoretical concept
You are at 10 000’ and your altimeter setting is 29.62”. What is your pressure altitude?
10,300’
You are at the ocean side; atmospheric pressure is 29.92” and temperature is 10°C. What is your density altitude?
3600 feet
Describe how the Koch chart is used
What is Fennel’s law?
Wind in the northern hemisphere is always deflected to the right
What is the coriolis force?
The force which pulls an object to the right (clockwise) in the northern hemisphere and to the left (anticlockwise) in the southern hemisphere
An aircraft is flying in a straight line through space. Due to the coriolis effect, in which direction does the aircraft appear to be veering?
Right in the northern hemisphere or left in the southern hemisphere
What is surface friction?
Friction between the surfaceon the earth and the atmosphere that will slow the movement of air
What is the relationship between surface friction and air’s ability to flow into a low?
The greater the surface friction, the more directly air flows into a low
What is the relative windspeed around a high and a low?
Wind speed is higher around a high and lower around a low
What is Buy Ballot’s law?
Standing with your back to the wind, the low is on your left and the high is on your right
Explain the movement of air in high and low pressure areas in terms of convergence and divergence
Explain how the land and sea breeze cycles
Explain the difference between katabatic and anabatic winds
Explain the movement of wind as it comes in contact with a mountain range