Met Flashcards
What gasses are the atmosphere made up of?
Nitrogen, Oxygen, Trace gasses (CO2, Neon, Helium, methane etc)
What are the variable constituents in the atmosphere?
Solids (dust, salt, volcanic ash) Liquids - Water Droplets Gases - Water vapour and other gasses
How does Carbon Dioxide affect the atmosphere?
Although the quantity is relatively low, it contributes to temperature control by absorbing heat in certain long radiation wavebands.
What effect does Oxygen have on the atmosphere?
Oxygen dissociates from the molecular form (O2) to the atomic form (O) under the influence of short wave solar radiation. Some re-combination of O and O2 takes place to form Ozone (O3), which absorbs more short wave radiation. These processes combine to produce relatively warm layers in the higher parts of the atmosphere.
Water appears in what 5 forms in the atmosphere?
Fog Mist Cloud Ice Precipitation
What effect do solid particles have on the atmosphere?
Solid Particles promote the formation of water droplets by providing condensation nuclei. Large quantities can reduce visibility (eg sand storms or smoke haze)
Label the image of the layers of the atmosphere.
Where is all of the atmospheric water, and therefore weather, located?
Troposphere
How do the following get affected by an increase in height in the troposphere?
Temperature
Pressure
They all decrease with an increase in height
How are the following affected by an increase in height in the stratosphere?
Temperature
Pressure
Temperature increases (inversion)
Pressure decreases
In which season is the Tropopause highest?
Summer
At what rate does pressure decrease with height near the ground?
1 hPa per 30 ft
At what rate does pressure decrease with height at 20 000 ft and above?
1 hPa per 50 ft
An increase in temperature causes what change to the density?
Increase in temperature causes a decrease in density
An increase in pressure has what effect on density?
An increase in pressure is related to an increase in density
What is the ideal gas equation?
ρ=p/RT
Where ρ is density, p is pressure, R is the Gas constant, and T is the absolute Temperature
What does the image depict, and what will this measure?
Aneroid Barometer
Pressure measurement
What is the ICAO average state of the atmosphere called?
International Standard Atmosphere (ISA)
What is the ISA Sea Level Pressure?
1013.2 hPa
What is the ISA Sea-Level Temperature?
15°C
What is the ISA height of the Tropopause?
36 090 ft
What is the ISA Temperature at the Tropopause?
-56.5°C
What is the ISA Sea-Level Density?
1.225 kg/m³
What is the ISA temperature lapse rate in the Troposphere?
1.98°C per 1000 ft
What is the ISA Temperature of the Tropopause?
-56.5°C
How much (as a percentage) of the solar radiation is absorbed by the Earth?
70%
What is the intensity of incoming solar radiation on an object, measured as the solar input on a horizontal surface?
Insolation
What 5 factors affect insolation?
Earth/Sun distance in the elliptical orbit
Seasonal variations
Latitude
Time of day
Atmospheric conditions
Describe convection.
When fluid particles are heated, their density decreases, and therefore the heated particles rise above the cooler particles. This transfers heat through the fluid by causing the particles to move in a convection current.
What is the measure of water vapour (moisture) in the air, regardless of temperature. expressed as grams of moisture per cubic meter of air (g/m³)?
Absolute Humidity.
What is a ratio, expressed as a percentage, of the actual water vapour content of a sample of air to the maximum it could hold at its temperature?
Relative humidity.
What is the temperature (given in degrees) at which the air is saturated with water vapor?
Dew Point
What is the heat absorbed or released when it changes substance?
Latent Heat
What is a liquid changing into a gas called?
Evaporation
What is the change from water vapour to water called?
Condensation
Does Evaporation warm up or cool down the surface the water is on?
Cools down the surface.
(Hence why sweating cools us down)
Does condensation in the atmosphere cause the surrounding atmosphere to warm up or cool down?
Warm up
(think pint warming up with condensation on the glass)
What change of state is the transition from a solid to gas?
Sublimation (or vaporisation)
What is the name of the change of state from a gas to solid?
Deposition
Why are condensation trails produced?
Water vapour from an aircraft’s exhaust gases has to condense as the air is cooled by the surrounding air.
This normally happens higher up in the atmosphere.
What is any type of water particle that form in the atmosphere and fall to the ground?
Precipitation
What are the 6 parts of the water cycle?
Evaporation
Condensation
Precipitation
Accumilation
Surface Runoff
Infiltration
What is the speed at which the temperature changes with altitude?
Temperature Lapse Rate
What is the rate at which air cools as it rises when the air is unsaturated?
Dry Adiabatic Lapse Rate (DALR)
What is the rate at which air cools as it rises when the air is at 100% relative humidity?
Saturated Adiabatic Lapse Rate (SALR)
What is the standard dry adiabatic lapse rate?
3°C / 1000ft
What is the standard SALR?
1.5°C / 1000ft
What is the actual rate of temperature change with altitude for a specific time and location, obtained from a radiosonde?
Environmental Lapse Rate
Label this ELR graph.
What type of inversion is described below?
Air meets a colder surface and cools
Common on clear nights, when the ground cools rapidly due to radiation
Ground Inversion
What type of inversion is described below?
Immobile air overlies turbulent air
Vertical mixing in the turbulent layer carries heat down
Air cools more than the air above
Turbulence
What type of inversion is described below?
Sinking air layer is compressed and heated by increased pressure
This reduces the lapse rate and cools the air
Subsidence
What type of inversion is described below?
A cold air mass undercuts a warm air mass, lifting it
Has considerable slope, where other inversions are nearly horizontal
Frontal
What are the three types of stability?
Absolute Stability
Absolute Instability
Conditional Instability
If the ELR is 1°C/1000ft, is the atmosphere stable, instable or conditionally instable?
Absolute Stability
(ELR < SALR)
If the ELR is 4°C/1000ft, is the atmosphere stable, instable or conditionally stable?
Absolute instability
(ELR > DALR)
If the ELR is 2°C/1000ft, is the atmosphere stable, instable or conditionally instable?
Conditional Instability
(DALR>ELR>SALR)
Will a pocket of saturated air in a conditionally instable atmosphere rise or fall?
Saturated air will rise in a conditionally instable atmosphere
Will a pocket of unsaturated air rise or fall in a conditionally instable atmosphere?
Unsaturated air will sink in a conditionally instable atmosphere.
Compelete the following statement:
______ areas are warmer and have _____ pressure, whereas ______ regions are cooler and have _____ pressure.
Equatorial regions are warmer and have lower pressure, whereas Polar regions are cooler and have higher pressure.
What are lines of equal pressure at a specific height, typically mean sea level?
Isobars
WHat is a line connecting points of equal temperature?
Isotherms
What are the three forces that act on wind?
Pressure gradient force
Coriolis force
Friction
Briefly describe the Coriolis effect.
Due to the rotation of the Earth, in the Northern Hemisphere, the Coriolis force acts at 90° to the right of the pressure gradient force.
What is the name of wind that moves parallel to isobars?
Geostrophic wind.
What effect does frction have on wind?
Slacks (slows down)
Backs (moves N since C.E is reduced and PGF remains unchanged)
What is short-period and small-scale fluctuations in wind called?
Turbulence
What type of wind is the following describing?
During the day, the land heats faster than water. The warm air above the land rises, causing a convection current.
Sea Breeze
What type of wind is the following describing?
Land cools faster at night. Warm air over the water rises. Cooler, denser air from the land replaces it.
Land Breeze
What type of wind is the following statement describing?
Forms when two layers of air with equal pressure, but differing temperatures, meet. Wind direction is horizontal along isotherms. Speed is proportional to the mean temperature difference in the intervening column of air.
Thermal wind
What type of winds are the following statements decribing?
Wind blows +/-30° to ridge. Layer of stability over the mountain. Air accelerates over the mountain peak, then deflects upwards from the ground and downwards from the layer of stable air, creating a wave-like pattern of wind downwind of the mountain.
Standing waves
(aka mountain waves or lee waves)
What type of wind is the following statement describing?
Wind is funneled through a gap, causing greatly increased wind speed and turbulence between two hills.
Valley winds.
What type of wind is the following statement describing?
During the day, the surface of the slope is heated. The warm, less dense air rises up the slope.
Anabatic
(Ana like to walk up hills during the day)
What type of wind is the folowing statement describing?
At night the surface of a slope cools, the air cools and flows down the slope.
Katabatic winds
(Lazy cats roll down the hill at night)
What is the following statement describing?
Air is forced upwards and cools at the DALR. Once the air reaches the dew point, it cools at the SALR, causing the moisture to condense as clouds and precipitation, removing moisture from the air. On the other side, the dry air warms at the DALR as it descends down the slope. The resulting wind is drier and warmer on the downwind side than on the upwind side at the same height.
Foehn Effect
