MET PRT01 Flashcards
The atmosphere is defined
a collection of gasses surrounding the earth held by gravity
constant up to 60 km
Gasses in the atmosphere
78% nitrogen 21% oxygen 0.95% argon
Troposphere is
poles: 8km
Avg: 11 km (45 lat)
Equator: 16
Temp defines tropopause height
upper boundry tropopause
Tropopause folds
40 N/S
55 N/S (polarfront)
60/70 N/S
tropopause temp
Poles: -50
Equator: -80
Increase with LAT
Stratosphere extends
up to 50km
and contains Ozon (O3)
Max Ozon presense
around 20-25 km around +20 degress
The mesospere extends
80-90 km
The Ionosphere extends
Kennely: 110 km
Heavyside: 160 km
Appleton: 250 km
ISA extends to
32 km (100000 feet)
ISA temp decrease up to
11 km (-56.5c)
ISA temp increase at
20 km
Warmed by Ozon
Above the tropopause, how does temperature vary with increasing altitude in the ICAO standard atmosphere?
Select one:
a. At first it decreases and then higher up it remains constant
b. Continually increases
c. Continually decreases
d. Remains constant then increases
d. Remains constant then increases
Which is true of the temperature at the tropopause?
Select one:
a. There is no significant difference with change of latitude
b. It is highest in middle latitudes
c. It is colder in tropical regions than in polar regions
d. It is higher in equatorial regions than in Polar Regions
c. It is colder in tropical regions than in polar regions
In mid-latitudes the stratosphere extends on average from:
Select one:
a. 85 km to more than 200 km
b. 0 km to 11 km
c. 11 km to 50 km
d. 50 km to 85 km
c. 11 km to 50 km
Warmfront stretches
Stratiform clouds: 600 nm
Precipitaion: 200/300 nm (fine rain/drizzle possible snow)
Coldfront slope…
1:80
Coldfront stretches
slope: 100/200 nm
precipitation: 50/100 nm
Warmfron slope…
1:150
Pressure lapse rate (warm air)
Decreases
Pressure lapse rate (cold air)
increases
Pressure in the atmosphere drecreases at a
Decreasing rate
QFF is ….
the barometric pressure at a location corrected to MSL using the prevailing TEMPERATURE
Isobars are which Q values?
QFF
the barometric pressure at a location corrected to MSL using the prevailing TEMPERATURE
A trough (isobaric trough) of low pressure is:
Select one:
a. A small low established within the circulation of another low.
b. An area where the pressure is lower than anywhere else in the area.
c. A centre of pressure
surrounded on all sides by higher pressure.
d. An extension or elongation of a low pressure system along an axis on each side of which pressure increases.
d. An extension or elongation of a low pressure system along an axis on each side of which pressure increases.
The ICAO standard Atmosphere, assumes that the sea level atmospheric pressure is?
Select one:
a. 1013.25 hPa and decreases with an increase in height.
b. 1013.25 hPa and increases with an increase in height.
c. 1013.25 hPa and falls to about half this value at 30,000 ft.
d. 1013.25 hPa and decreases with an increase in height up to the tropopause. Above the tropopause it remains constant.
a. 1013.25 hPa and decreases with an increase in height.
Pressure decreases with height at a decreasing rate. This rate is modified by air temperature.
What happens to the pressure at any given height above warm air compared to cold air?
Select one:
a. Greater
b. Depends on the pressure system.
c. Lower
d. The same.
a. Greater
In the upper part of the stratosphere the temperature:
Select one:
a. is almost constant
b. decreases with altitude
c. increases with altitude
d. increases at first and decreases afterward
c. increases with altitude
Above the tropopause and within the lower part of the stratosphere (11 km to 20 km)the temperature remains constant. However, the upper part of the stratosphere (from 20 km), the temperature increases with height due to the absorption of UV rays by Ozone.
In mid-latitudes the stratosphere extends on average from:
Select one:
a. 85 km to more than 200 km
b. 0 km to 11 km
c. 11 km to 50 km
d. 50 km to 85 km
c. 11 km to 50 km
The tropopause in mid latitudes is:
Select one:
a. Lower in summer with a lower temperature.
b. Lower in winter with a higher temperature.
c. Lower in summer with a higher temperature.
d. Lower in winter with a lower temperature.
b. Lower in winter with a higher temperature.
Surface temperature controls tropopause height. Cold air will cause the tropopause to lower. The lower the tropopause the warmer is becomes.
Which one of the following statements applies to the tropopause?
Select one:
a. It separates the troposphere from the stratosphere
b. It is, by definition, an isothermal layer
c. It is, by definition, a temperature inversion
d. It indicates a strong temperature lapse rate
a. It separates the troposphere from the stratosphere
What is the most likely temperature, and height, at the polar tropopause?
Select one:
a. -75°C at 8 km
b. -56.5°C at 16 km
c. -25°C at 4 km
d. -40°C at 8 km
d. -40°C at 8 km
The polar tropopause is lower and warmer (6/8 km and -40°C) than the tropical tropopause (16-18 km and -75°C).
Density is..
Mass pr unit volume
at altitude, density ______ with latitude
Decreases
Due to pressure lapse rate being greater in cold air
at the surface, density _____ with latitude
Increases
Due to temperature at the surface
Density altitude formula…
Pressure altitude + (ISA dev x 118.8 ft)
Density at the surface will be high when:
Select one:
a. Pressure is high and temperature is low.
b. Pressure is low and temperature is high.
c. Pressure is high and temperature is high.
d. Pressure is low and temperature is low
a. Pressure is high and temperature is low.
Generally as altitude decreases:
Select one:
a. Temperature, pressure and density increase.
b. Temperature, pressure and density decrease.
c. Temperature decreases and density increases.
d. Temperature and pressure increase and density decreases.
a. Temperature, pressure and density increase.
If the outside air temperature at a given altitude is colder than ISA, the density altitude will be:
Select one:
a. Lower than true altitude.
b. Higher than pressure altitude.
c. Lower than pressure altitude
d. The same as the pressure altitude
c. Lower than pressure altitude
If the air is colder, then the density will increase. This higher density corresponds to a lower altitude in ISA, therefore the density altitude decreases.
At FL180 the air temperature is -35°C. The air density at this level is:
Select one:
a. equal to the density of the ISA at FL180
b. less than the density of the ISA at FL180
c. unable to be determined without the QNH
d. greater than the density of the ISA at FL180
d. greater than the density of the ISA at FL180
The air temperature is colder than normal, since ISA says the temperature should be -21. Therefore since it’s colder, the density will be greater than normal.
Tropical revolving storms are generally known as….
Hurricanes, Cyclones or Typhoons
700 NM wide
Subsidence is…
sinking air
Warm anti-cyclones are found at….
areas of excess air aloft
The Hadley Cell (20 lat)
The Ferrel Cell (45 lat)
Subtropical highs move
north in summer, and south in winter
Cold anti-cyclones are found in ……
Siberia and North america, over large land areas.
Weaker can be found over the poles
This causes a slow divergence of cold air
Temperary anti-cyclones moves…..
West to east
subsidens inversions have this effect on visibility
Traps polluted air in the ‘Cold’ zone near the ground
Ridges forms…
Outwards from the Cyclone, between two anti-cyklones!
A COL is found
Between two highs, and two lows where the isobars are widely spread!
Summer: Thunder
Winter: Fog
xtensive cloud and precipitation is often associated with a non frontal thermal depression because of :
Select one:
a. surface divergence and upper level convergence causing widespread ascent of air in the depression
b. surface convergence and upper level divergence causing widespread descent of air in the depression
c. surface divergence and upper level convergence causing widespread descent of air in the depression
d. surface convergence and upper level divergence causing widespread ascent of air in the depression
d. surface convergence and upper level divergence causing widespread ascent of air in the depression
Because the air rises it will expand and cool. If there is moisture present then vertical condensation will take place and vertical clouds will form. Vertically developed clouds are named “Cumulus” clouds.
How do air masses move at a cold front?
Select one:
a. Cold air overrides a warm air mass
b. Warm air undercuts a cold air mass
c. Cold air undercuts the warm air
d. Warm air overrides a cold air mass
c. Cold air undercuts the warm air
The cold advances against the warm, but since it colder and therefore denser than the warm air, the cold air will slide under the warm air. This is called “undercutting”
What weather can be expected in a small scale thermal depression or heat low?
Select one:
a. Active Cumulus clouds
b. No cloud
c. Thin high cloud
d. Thick layered cloud
a. Active Cumulus clouds CorrectThe vertically rising air cools and condenses to form vertical cloud
With the approach of a typical polar front depression from the Atlantic, what sequence of fronts would you expect to observe on the western coasts of Europe?
Select one:
a. A warm front only
b. A cold front followed by a warm front
c. A cold front only
d. A warm front followed by a cold front
d. A warm front followed by a cold front
Which cloud type is usually the first cloud to be observed with an approaching warm front?
Select one:
a. Nimbostratus
b. Cumulus
c. Cirrus or cirrostratus
d. Altostratus
c. Cirrus or cirrostratus
This is the cloud type found at the very top edge of the warm front. It is wispy. As the warm front approaches the cloud will eventually lower and thicken.
A ridge of high pressure is generally associated with:
Select one:
a. Divergence at the surface causing an improvement in the surface visibility.
b. Subsidence of air, then divergence at the surface, causing clear skies and good weather.
c. Convergence at the surface causing increased cloud and precipitation.
d. Divergence at the surface causing cloud to break up and more precipitation.
b. Subsidence of air, then divergence at the surface, causing clear skies and good weather.
Because a ridge is simply an old shaped high pressure, it will hold the characteristics of normal high pressures.
Where are you likely to find the strongest winds close to the ground?
Select one:
a. At the centre of a low-pressure system
b. At the centre of a high-pressure system
c. In the transition zone between two air masses
d. Where there is little variation in pressure over a large area during the winter months
a. At the centre of a low-pressure system
Which of the following is common on a cold front but NOT on a warm front?
Select one:
a. Drizzle
b. Cumuliform cloud
c. Heavy rain
d. Stratus
b. Cumuliform cloud
Cold front tends to have cumuliform clouds embedded in the part of the cold front that curls back near the surface. These clouds produce showery precipitation. Cumulus cloud are very rarely found on warm fronts.
In special circumstances, thermal depressions or heat lows found close to the equator can organise themselves and develop into an exceptionally hazardous weather phenomena called?
Select one:
a. Squal lines
b. Tropical Revolving Storms
c. Tornadoes
d. Anticyclones
b. Tropical Revolving Storms
