Meteorology Flashcards
What conditions are required for airframe ice to form?
Visible moisture is required.
Temps below freezing point.
How does a tornado form?
When rotational velocity below a Cumulonimbus is increased due to surface convergence.
What are the characteristics of a heat type (convective localized) thunderstorm?
More common in afternoons & can persist for long periods of time.
What type of cloud is most likely to cause the formation of rime ice?
Altostratus
Where will clear ice form in relation to the freezing level
Between the freezing level & 6000/8000ft above the freezing level
What is the most predominant method through which cooling, leading to cloud formation takes place?
Widespread ascent of air
How does the adiabatic process affect anabatic winds?
The adiabatic cooling of rising air helps to oppose the upwards flow
When air with few condensation nuclei is cooled & condensation is delayed beyond the temperature where it should have occurred, the condition is known as what?
Super saturation
What is occurring when the process of conduction is taking place
Contact occurs between molecules at different temperatures & sensible heat is transferred.
What is the primary factor which determines the stability of an airmass?
Environmental temperature lapse rate (ELR)
An adiabatic lapse rate means the rate of change in what?
Temperature within parcels of air as a result of compression or expansion
What are the characteristics of an orographic thunderstorm
Long lasting with heavy precipitation
Two columns of air have the same QNH, if the pressure indicated on a barometer at 10000” in the warm column is 700hPa, what will the barometer indicate when placed in the cold column at the same altitude?
Less than 700hPa
During winter months when comparing the surface air temps & pressure in continental regions with these in oceanic regions, it can be said that in continental regions generally?
The temps are lower & pressures are higher
What occurs over the land to terrestrial radiation, conduction & convection during a clear Nighy that follows a sunny winters day.
Terrestrial radiation, convection & conduction all continue.
Describe the process involved in the formation of freezing rain.
Rain drops fall through a layer of freezing air, become super cooled & form clear ice upon contact with an object.
Does the amount of water content in the cloud effect the rate of ice accretion?
Yes, the higher the water content the greater the rate of ice accretion.
The temperature of the Troposphere is most influenced by heating from what?
Below by terrestrial radiation & convection
What is the process whereby microbursts can occur beneath high base mature CB’sc with warm dry air beneath the base?
Descending rain from the CB evaporates & in doing so draws large amounts of latent heat from the air, cooling the air & creating a microburst substantially cooler than the environment air
Define QNH
Aerodrome level pressure corrected to MSL using ISA temp lapse rates. When set on altimeter, the instrument will read altitude above MSL
What is hail?
Ice embryo gaining a layer of rime ice on an updraft, then a layer of clear ice on a downdraft & once too heavy to be supported, falls, or ejected as hail.
What is cold advection?
Cold air moving towards warmer regions.
Lower layers will heat up creating instability.
What is warm advection?
Warm air moving towards colder regions.
Lower layers cool, condense & usually form stable, layer type cloud.
What causes dissipation of radiation fog?
- An increase in wind dispersing the warm vs cold layers.
- Sun’s heat penetrates fog & warms the earth thus evaporating water droplets from ground up.
