Meterorology Theory Part 1 Flashcards
What percent water vapour is in the air?
0-5%
What is the temperature at the Tropopause?
Minus 56.5 degrees Celsius
Define Temperature
Temperature:
A measure of the average kinetic energy contained in a substance; the more kinetic energy the more molecules move and collide with each other
Define Heat
Heat Energy:
• A measure of the energy that may be transferred from one body to another
• Often an input of Heat
Energy = an increase in
temperature
Define adiabatic heating/coolong
Change in temperature WITHOUT the transfer of heat energy
What is the relationship between temperature and moisture?
The higher the temperature the greater the amount of water vapour can be held in a parcel of air
What is saturated air?
Air that contains all the water vapour it can hold at a given temperature.
The temperature at which a parcel of air reaches 100% saturation
Dew point temperature
Relative Humidity
Amount of water vapour in the air divided by the amount of water at saturation x 100
Fog or mist is likely when
There exists a narrow Temp/dew point spread (3 degrees C or less) AND there exists Moderate temperatures (5-20 degrees)
The horizontal mo movement of air from regions of high pressure to regions of low pressure is known as
Wind
A clockwise change in wind direction is called
Veering
A counter-clockwise change in wind direction is called
Backing
Define cyclonic flow
Air moves counter-clockwise and into the centre of a low
Air Convergence
Usually accompanies cyclonic flow and air meets in the middle and rises.
Rising air cools adiabatically, and clouds tend to form in what type of high or low system?
Low because of the air expands, it cools and gives off clouds.
Anti-cyclonic flow air moves _____
Clockwise and outward from a high.
Usually, high pressure is accompanied by _____
Subsidence (descending air) that causes adiabatic heating and acts against cloud formation.
With regards to wind, what is likely to happen below 3000 feet AGL?
The wind will back in direction and decrease in speed. That’s because below 3000 feet AGL friction with the earth becomes a factor.
Above 3000 feet AGL, wind will
Flow parallel to the isobars
If isobars are close together, wind will be ______
Strong
If isobars are relatively far apart, then the wind will be…
Relatively weaker
With regards to isobars, how will the wind flow?
Wind flows parallel to the isobars
Prevailing winds in the Arctic are
Polar Easterlies.
Water heats up _____ and cools down _____ than air
Slower, slower
Define Air Mass
A large section of the troposphere with uniform properties of temperature and moisture content.
What characterizes a continental air mass?
Dry - air mask forms over Oceans
What character characterizes a maritime air mass?
Moist - air mask forms over Oceans.
What are the characteristics of an arctic air mass?
Cold air-forms in the high Arctic
What are the characteristics of a polar air mass?
Cool air forms in subpolar regions
What are the characteristics of a tropical air mass?
Warm air forms in tropical regions
A narrow transition zone between two air masses is known as
A front
Frontal passage will always bring changes in:
Temperature
Barometric pressure
Wind speed
Wind direction
What are the effects on temperature, barometric pressure, and wind when a COLD front passes?
Temperature-dramatic decrease
Barometric pressure-dramatic decrease as front approaches, steady rise as front passes
Wind speed and direction-wind will veer and increase, may become gusty
A warm front is better defined as
The trailing edge of a retreating cold air mass.
What are the effects on temperature, barometric pressure, and wind when a WARM front passes?
Temperature - gradual increase
Baro - gradual decrease as the front approaches, then small decrease as the front pass
Wind - wind will veer and increase, smaller changes than in a cold front
Define Occluded Front
When warm air is cut off from the ground by a cold air mass
What are the characteristics of an occluded front?
Slow moving
Weather associated last a long time
Regardless of type of front, Frontal weather depends on 3 things.
- Moisture Content of warm air mass
- Stability of warm air mass
- Speed / Steepness of Front
Result of a cold front:
Result of a warm front:
