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KMA Grade 9 Meteorologist study materials
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KMA Grade 9 Meteorologist practice questions

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Question 1Meteorology (general and dynamic meteorology)

In the standard atmosphere, the environmental lapse rate in the troposphere is approximately what value?

  1. 6.5 °C per kilometre Correct answer.
  2. 2.0 °C per kilometre
  3. 0.65 °C per kilometre
  4. 9.8 °C per kilometre

Explanation

The International Standard Atmosphere assumes a tropospheric temperature decrease of about 6.5 °C for every kilometre of ascent up to the tropopause. This value is an average of the real atmosphere, not a physical constant, and actual soundings often differ from it.

Question 2Meteorology (general and dynamic meteorology)

A rising air parcel cools at the dry adiabatic lapse rate until it reaches saturation. What is that dry adiabatic rate?

  1. About 10 °C per kilometre Correct answer.
  2. About 6 °C per kilometre
  3. About 15 °C per kilometre
  4. About 3 °C per kilometre

Explanation

An unsaturated parcel expands and cools adiabatically at roughly 9.8 °C per kilometre, conventionally rounded to 10 °C per kilometre. This rate follows from the first law of thermodynamics applied to a parcel with no latent heat release.

Question 3Meteorology (general and dynamic meteorology)

Which force must balance the pressure gradient force to produce a geostrophic wind?

  1. The gravitational force alone
  2. The centrifugal force
  3. The Coriolis force Correct answer.
  4. The frictional force

Explanation

Geostrophic balance is a two-force balance between the horizontal pressure gradient force and the Coriolis force. The result is flow parallel to straight isobars with no acceleration. Friction and centrifugal effects are excluded from the geostrophic definition.

Question 4Meteorology (general and dynamic meteorology)

In the Northern Hemisphere, air flowing aloft parallel to straight isobars has low pressure to which side of the flow direction?

  1. To the right
  2. To the left Correct answer.
  3. Directly ahead
  4. Directly behind

Explanation

In geostrophic flow the Coriolis force acts to the right of the wind in the Northern Hemisphere, so the pressure gradient force must point left, meaning lower pressure lies to the left. This is a direct consequence of geostrophic balance.

Question 5Meteorology (general and dynamic meteorology)

What primarily drives the global-scale meridional transport of energy from the tropics toward the poles?

  1. Radiative diffusion through still air
  2. Latent heat release confined to the tropics
  3. Atmospheric and oceanic circulation systems Correct answer.
  4. Molecular conduction in the upper atmosphere

Explanation

The tropics receive a net radiative surplus while the poles run a deficit, and the imbalance is resolved mainly by atmospheric winds and ocean currents. These circulations, including the Hadley cells and mid-latitude eddies, carry heat poleward.

Question 6Meteorology (general and dynamic meteorology)

Which cloud genus consists of thin, wispy, high-altitude ice-crystal clouds?

  1. Altostratus
  2. Stratocumulus
  3. Cirrus Correct answer.
  4. Nimbostratus

Explanation

Cirrus clouds form in the upper troposphere where temperatures are cold enough for ice crystals, giving them a fibrous, wispy appearance. Their high base and ice composition distinguish them from the lower, water-dominated genera.

Question 7Meteorology (general and dynamic meteorology)

Which instrument measures atmospheric pressure directly?

  1. Anemometer
  2. Hygrometer
  3. Ceilometer
  4. Barometer Correct answer.

Explanation

A barometer measures atmospheric pressure, either through a mercury column or an aneroid capsule. Pressure is a fundamental variable for analysing synoptic systems and altimetry.

Question 8Meteorology (general and dynamic meteorology)

At what local time is the daily maximum surface air temperature usually observed on a clear day?

  1. Mid to late afternoon Correct answer.
  2. Just after sunrise
  3. Around midnight
  4. Around solar noon

Explanation

Surface temperature peaks in mid to late afternoon because incoming solar heating continues to exceed outgoing longwave cooling for several hours after noon. The lag between peak solar elevation and peak temperature reflects the ongoing energy accumulation.

Question 9Meteorology (general and dynamic meteorology)

An air parcel with a temperature of 20 °C is placed in an environment at 15 °C. If the parcel is unsaturated, what happens?

  1. It cools immediately to match the environment
  2. It accelerates upward because it is buoyant Correct answer.
  3. It remains stationary because pressures are equal
  4. It sinks because it is colder than the environment

Explanation

An unsaturated parcel warmer than its surroundings is less dense and therefore positively buoyant, so it accelerates upward. This is the criterion for absolute instability when the environmental lapse rate exceeds the dry adiabatic rate.

Question 10Meteorology (general and dynamic meteorology)

If the environmental lapse rate is 12 °C per kilometre, how is the layer described for both saturated and unsaturated parcels?

  1. Absolutely stable
  2. Conditionally unstable
  3. Absolutely unstable Correct answer.
  4. Neutral for saturated ascent

Explanation

An environmental lapse rate steeper than the dry adiabatic rate (about 10 °C per kilometre) means a parcel is buoyant whether or not it is saturated. Such a layer is absolutely unstable.

Question 11Meteorology (general and dynamic meteorology)

Why does the saturated adiabatic lapse rate decrease as air temperature increases?

  1. Warmer air holds more water vapour, so more latent heat is released per degree of cooling Correct answer.
  2. Pressure decreases faster in warm air, reducing adiabatic cooling
  3. The dry adiabatic rate rises with temperature, lowering the saturated rate
  4. Colder air contains more water vapour and releases latent heat more slowly

Explanation

The saturated adiabatic rate depends on how much latent heat condenses per unit of cooling. Warm air has a higher saturation mixing ratio, so a given cooling step condenses more vapour and offsets more of the adiabatic cooling, giving a smaller lapse rate.

Question 12Meteorology (general and dynamic meteorology)

A parcel at the surface has a temperature of 25 °C and a dew point of 15 °C. Using a dry adiabatic rate of 10 °C per kilometre and a dew-point lapse of about 2 °C per kilometre, roughly what is the lifting condensation level?

  1. About 2.5 kilometres
  2. About 5 kilometres
  3. About 1.25 kilometres Correct answer.
  4. About 0.5 kilometres

Explanation

The temperature–dew-point spread of 10 °C closes at the rate of the difference between the two lapse rates, about 8 °C per kilometre. Dividing the 10 °C spread by 8 °C per kilometre gives roughly 1.25 kilometres.

Question 13Meteorology (general and dynamic meteorology)

In the Northern Hemisphere boundary layer, friction causes the surface wind to do what relative to the geostrophic wind?

  1. Cross the isobars toward higher pressure
  2. Blow exactly parallel to the isobars
  3. Cross the isobars toward lower pressure Correct answer.
  4. Reverse direction and blow down the pressure gradient

Explanation

Friction slows the wind, reducing the Coriolis force so that the pressure gradient force turns the flow toward low pressure. This produces cross-isobar inflow at the surface and convergence into low-pressure systems.

Question 14Meteorology (general and dynamic meteorology)

Which statement correctly describes the vertical structure of a mature mid-latitude cyclone?

  1. The system is vertically stacked and warm-core at all levels
  2. The low-pressure centre tilts westward with height and the system is cold-core aloft Correct answer.
  3. The system has no vertical tilt and is cold-core at all levels
  4. The low-pressure centre tilts eastward with height and the system is warm-core aloft

Explanation

A mature baroclinic cyclone tilts west or northwest with height, with the upper trough located upstream of the surface low. The associated cold-core upper structure supports the surface circulation through vorticity advection and thermal wind balance.

Question 15Meteorology (general and dynamic meteorology)

According to the thermal wind relationship, how does the vertical shear of the geostrophic wind relate to the horizontal temperature gradient?

  1. The thermal wind is independent of the horizontal temperature gradient
  2. The thermal wind blows with colder air to its right in the Northern Hemisphere
  3. The thermal wind is parallel to the temperature gradient
  4. The thermal wind blows with colder air to its left in the Northern Hemisphere Correct answer.

Explanation

The thermal wind is the vector difference between geostrophic winds at two levels, and it blows parallel to the mean isotherms with cold air on the left in the Northern Hemisphere. It arises because the geostrophic wind increases with height more rapidly in cold, dense air columns.

Question 16Meteorology (general and dynamic meteorology)

What is the primary role of the Coriolis force in the formation of a geostrophic wind?

  1. It generates the horizontal temperature gradient
  2. It deflects the moving air until it balances the pressure gradient force Correct answer.
  3. It accelerates air directly down the pressure gradient
  4. It removes the pressure gradient force from the momentum balance

Explanation

As air begins to move under the pressure gradient force, the Coriolis force deflects it to the right in the Northern Hemisphere. The deflection continues until the Coriolis force exactly opposes the pressure gradient force, leaving flow parallel to the isobars.

Question 17Meteorology (general and dynamic meteorology)

Why does the wind generally increase in speed with height in the friction layer?

  1. The Coriolis force weakens with height and allows faster flow
  2. Friction decreases with height, so the wind approaches geostrophic balance and speed Correct answer.
  3. Pressure gradients are strongest at the surface and weaken with height
  4. Air density increases with height and accelerates the wind

Explanation

Friction is strongest near the surface and diminishes upward, so the Coriolis deflection grows and the wind turns toward geostrophic direction while accelerating. The result is a wind profile that backs with height in the Northern Hemisphere boundary layer.

Question 18Meteorology (general and dynamic meteorology)

What is the primary reason the equatorial regions receive more solar radiation annually than the poles?

  1. The atmosphere is thinner near the poles, absorbing more radiation
  2. The solar angle is higher and the path through the atmosphere is shorter at low latitudes Correct answer.
  3. The poles are farther from the Sun in all seasons
  4. Cloud cover is greater at the equator, trapping more heat

Explanation

Near the equator the Sun is high in the sky, so incoming radiation strikes the surface more directly and travels a shorter slant path through the atmosphere. Both effects concentrate energy per unit area compared with the poles.

Question 19Meteorology (general and dynamic meteorology)

In a hydrostatic atmosphere, what happens to pressure as you ascend through a layer of constant density?

  1. It increases linearly with height
  2. It remains constant with height
  3. It decreases exponentially with height
  4. It decreases linearly with height Correct answer.

Explanation

Hydrostatic balance gives a pressure decrease proportional to density times gravity times height. If density is constant, the pressure falls linearly with height rather than exponentially. Exponential decrease applies only when density itself decreases with height.

Question 20Meteorology (general and dynamic meteorology)

A sounding shows a surface temperature of 30 °C and a dew point of 22 °C. If the parcel is lifted to 1 kilometre, roughly what is its temperature, assuming a dry adiabatic rate of 10 °C per kilometre?

  1. 20 °C Correct answer.
  2. 8 °C
  3. 12 °C
  4. 30 °C

Explanation

An unsaturated parcel lifted 1 kilometre cools by about 10 °C, so 30 °C becomes roughly 20 °C. Because the dew point of 22 °C is reached before that level, the parcel would actually become saturated slightly below 1 kilometre and cool more slowly thereafter, but the dry-adiabatic estimate is the stated basis.

Question 21Meteorology (general and dynamic meteorology)

How does the release of latent heat during condensation affect the stability of a conditionally unstable layer?

  1. It has no effect because latent heat is released only at the surface
  2. It warms the parcel and makes the layer more unstable than a dry parcel would be Correct answer.
  3. It removes moisture and therefore always stabilizes the layer
  4. It cools the parcel and stabilizes the layer

Explanation

In a conditionally unstable layer the environmental lapse rate lies between the saturated and dry adiabatic rates. Once a parcel saturates, latent heating slows its cooling, making it warmer than a dry parcel would be and allowing deeper, more vigorous ascent.

Question 22Meteorology (general and dynamic meteorology)

Which combination of processes produces the strongest upper-level divergence favourable for surface cyclone deepening?

  1. Cold advection throughout the troposphere with no jet structure
  2. Positive vorticity advection and upper-level jet streak diffluence Correct answer.
  3. Negative vorticity advection and upper-level confluence
  4. Surface friction and boundary-layer convergence

Explanation

Cyclone development requires mass removal aloft, which is favoured by positive vorticity advection ahead of an upper trough and by the diffluent exit region of a jet streak. These processes generate upper-level divergence that draws air upward from the surface low.

Question 23Meteorology (general and dynamic meteorology)

In gradient wind balance around a Northern Hemisphere low-pressure centre, how does the gradient wind speed compare with the geostrophic wind for the same pressure gradient?

  1. It equals the geostrophic wind
  2. It is slower than the geostrophic wind Correct answer.
  3. It is faster than the geostrophic wind
  4. It reverses direction

Explanation

Around a low, the centrifugal force points outward, the same direction as the Coriolis force, so the pressure gradient force must balance both. For a given pressure gradient the resulting gradient wind is therefore subgeostrophic.

Question 24Meteorology (general and dynamic meteorology)

Why is the tropopause generally higher over the equator than over the poles?

  1. Colder surface temperatures at the equator allow the troposphere to expand
  2. Ozone concentrations are lowest at the equator and raise the tropopause
  3. The Coriolis force is strongest at the equator and lifts the tropopause
  4. Stronger convective heating and deeper tropospheric overturning extend the troposphere Correct answer.

Explanation

Vigorous convection in the tropics and the deep Hadley circulation carry the troposphere to greater heights, so the tropopause sits near 16–18 kilometres there. At the poles, weaker convection and cold, dense air produce a tropopause near 8–10 kilometres.

Question 25Meteorology (general and dynamic meteorology)

A parcel is displaced upward in a layer where the environmental lapse rate is 7 °C per kilometre. If the parcel is saturated, how does it behave?

  1. It sinks back because the saturated adiabatic rate exceeds the environmental rate
  2. It continues to rise because the saturated adiabatic rate is less than the environmental rate Correct answer.
  3. It rises only if it is unsaturated
  4. It stays at its new level because the two rates are equal

Explanation

In warm, moist conditions the saturated adiabatic rate is roughly 4–6 °C per kilometre, which is less than the 7 °C per kilometre environmental rate. The ascending saturated parcel therefore stays warmer than its environment and remains buoyant, a conditionally unstable situation that has been realized.

Question 26Meteorology (general and dynamic meteorology)

In a surface weather map, what does a line of constant pressure drawn at 4 hPa intervals represent?

  1. An isobar Correct answer.
  2. An isohyet
  3. An isotherm
  4. An isopleth of equal wind speed

Explanation

Isobars are lines connecting points of equal mean sea-level pressure, conventionally drawn at 4 hPa intervals on synoptic charts. They reveal pressure gradients and thus the strength of the pressure force.

Question 27Meteorology (general and dynamic meteorology)

Which atmospheric layer is characterised by a temperature that increases with height and contains most of the ozone that absorbs ultraviolet radiation?

  1. The thermosphere
  2. The stratosphere Correct answer.
  3. The troposphere
  4. The mesosphere

Explanation

The stratosphere lies above the troposphere and is marked by a temperature inversion because ozone absorbs solar ultraviolet radiation, heating the layer. This stable stratification suppresses vertical motion.

Question 28Meteorology (general and dynamic meteorology)

What primarily drives the horizontal movement of air that we call wind?

  1. The Moon's gravitational pull
  2. Horizontal pressure differences Correct answer.
  3. Differences in soil moisture
  4. The Earth's magnetic field

Explanation

Wind arises when horizontal pressure gradients exist; air accelerates from higher pressure toward lower pressure, modified by the Coriolis force and friction. The pressure-gradient force is the fundamental driver.

Question 29Meteorology (general and dynamic meteorology)

Which process transfers heat through the direct contact and molecular collision between a warm surface and the air immediately above it?

  1. Radiation
  2. Advection
  3. Convection
  4. Conduction Correct answer.

Explanation

Conduction is the transfer of heat by molecular contact, important only in the thin layer of air next to the ground. Convection and radiation dominate the larger-scale energy budget.

Question 30Meteorology (general and dynamic meteorology)

What is the standard sea-level pressure value used as a reference in meteorology?

  1. 980.00 hPa
  2. 1013.25 hPa Correct answer.
  3. 1050.00 hPa
  4. 1000.00 hPa

Explanation

The standard atmosphere defines mean sea-level pressure as 1013.25 hPa (1013.25 mb), equivalent to 29.92 inches of mercury. This value is used to reduce station pressure to sea level.

Question 31Meteorology (general and dynamic meteorology)

Which gas is the most abundant by volume in the Earth's lower atmosphere?

  1. Oxygen
  2. Argon
  3. Nitrogen Correct answer.
  4. Carbon dioxide

Explanation

Nitrogen makes up about 78% of the dry atmosphere by volume, followed by oxygen at about 21%. Argon and carbon dioxide are trace constituents.

Question 32Meteorology (general and dynamic meteorology)

What does a relative humidity of 50% indicate?

  1. The air contains 50 grams of water vapour per kilogram of dry air
  2. The dew point is 50 °C
  3. The air contains half the water vapour needed for saturation at that temperature Correct answer.
  4. Half of the atmosphere's mass is water vapour

Explanation

Relative humidity is the ratio of the actual vapour pressure to the saturation vapour pressure at the same temperature, expressed as a percentage. At 50%, the air holds half the vapour needed to become saturated.

Question 33Meteorology (general and dynamic meteorology)

In the Northern Hemisphere, air flowing aloft in a straight line at constant speed is directed with lower pressure to its left. What is this flow called?

  1. Thermal wind
  2. Geostrophic wind Correct answer.
  3. Ageostrophic wind
  4. Gradient wind

Explanation

Geostrophic flow is the exact balance between the horizontal pressure-gradient force and the Coriolis force for straight, frictionless flow. In the Northern Hemisphere the Coriolis force acts to the right of the wind, leaving lower pressure to the left.

Question 34Meteorology (general and dynamic meteorology)

A station at sea level reports a pressure of 1000 hPa. Using the approximate rule that pressure decreases by 1 hPa for every 8 metres of ascent near the surface, what is the pressure at 800 metres above sea level?

  1. 920 hPa
  2. 100 hPa
  3. 980 hPa
  4. 900 hPa Correct answer.

Explanation

The hypsometric relationship near the surface gives about 1 hPa per 8 m, so 800 m corresponds to 100 hPa. Subtracting this from 1000 hPa yields 900 hPa.

Question 35Meteorology (general and dynamic meteorology)

What is the primary reason that rising air cools at the dry adiabatic rate of about 9.8 °C per kilometre?

  1. Absorption of infrared radiation
  2. Expansion as pressure decreases Correct answer.
  3. Mixing with colder environmental air
  4. Loss of heat to the surrounding air

Explanation

An ascending parcel expands because ambient pressure falls, doing work on its surroundings at the expense of internal energy. This adiabatic cooling occurs without exchange of heat with the environment.

Question 36Meteorology (general and dynamic meteorology)

What does a wind barb with a full feather (long barb) represent on a surface weather map?

  1. 5 knots
  2. 50 knots
  3. 1 knot
  4. 10 knots Correct answer.

Explanation

On standard wind barbs, a full feather represents 10 knots, a half feather 5 knots, and a triangular pennant 50 knots. The staff points toward the direction from which the wind blows.

Question 37Meteorology (general and dynamic meteorology)

If the environmental lapse rate is 6 °C per kilometre and a parcel is unsaturated, how does the parcel's temperature compare with the environment after it is lifted 1 kilometre?

  1. The parcel remains the same temperature as the environment
  2. The parcel becomes saturated and warms
  3. The parcel becomes colder than the environment Correct answer.
  4. The parcel becomes warmer than the environment

Explanation

The parcel cools at about 9.8 °C per kilometre while the environment cools at 6 °C per kilometre. After 1 km the parcel is about 3.8 °C colder than its surroundings, so it is negatively buoyant and the layer is stable for unsaturated parcels.

Question 38Meteorology (general and dynamic meteorology)

What causes the seasonal variation in solar declination that produces the solstices?

  1. Changes in the Sun's energy output
  2. The ellipticity of Earth's orbit
  3. The tilt of Earth's rotation axis relative to its orbital plane Correct answer.
  4. The precession of the equinoxes

Explanation

Earth's axis is tilted about 23.5° from the normal to its orbital plane, so the subsolar point migrates between the tropics over the year. At the solstices the Sun is directly overhead at 23.5° latitude in one hemisphere.

Question 39Meteorology (general and dynamic meteorology)

In a Northern Hemisphere cyclone, how does the wind blow around the centre at the surface?

  1. Clockwise and outward
  2. Counterclockwise and outward
  3. Counterclockwise and inward Correct answer.
  4. Clockwise and inward

Explanation

Around a low-pressure centre in the Northern Hemisphere, the pressure-gradient force points inward while the Coriolis force deflects the wind to the right. The result is counterclockwise rotation with a component toward the low due to friction.

Question 40Meteorology (general and dynamic meteorology)

What is the primary effect of the release of latent heat in a deep cumulonimbus cloud?

  1. It warms the cloud column and can strengthen the updraft Correct answer.
  2. It increases the environmental lapse rate
  3. It decreases the saturation vapour pressure
  4. It cools the cloud top and weakens the updraft

Explanation

Condensation releases latent heat, warming the cloudy air relative to the environment and increasing its buoyancy. This positive feedback can sustain strong updrafts in deep convection.

Question 41Meteorology (general and dynamic meteorology)

What does the acronym METAR denote in aviation weather reporting?

  1. A warning of severe turbulence
  2. A routine aviation weather report Correct answer.
  3. A satellite cloud image
  4. A forecast for a specific airport

Explanation

METAR stands for Meteorological Aerodrome Report, a routine observation of surface weather at an airport, typically issued hourly. It includes wind, visibility, clouds, temperature, dew point, and pressure.

Question 42Meteorology (general and dynamic meteorology)

A parcel of air at 20 °C with a mixing ratio of 10 g/kg is lifted until it becomes saturated. If the saturation mixing ratio at the lifting condensation level is 8 g/kg, what happens to the excess water vapour?

  1. It remains as vapour in supersaturation
  2. It increases the parcel's temperature
  3. It condenses into liquid water Correct answer.
  4. It is converted into ozone

Explanation

When the mixing ratio exceeds the saturation mixing ratio, the air is supersaturated and the excess vapour condenses onto condensation nuclei. This condensation releases latent heat and forms cloud droplets.

Question 43Meteorology (general and dynamic meteorology)

What is the main reason that the wind at 500 hPa is generally stronger than the wind at 850 hPa in mid-latitudes?

  1. The air density is higher aloft
  2. Friction is greater aloft
  3. The Coriolis parameter is larger aloft
  4. The horizontal temperature gradient is typically larger aloft Correct answer.

Explanation

The thermal wind relation links vertical shear of the geostrophic wind to the horizontal temperature gradient. In mid-latitudes the temperature gradient between the tropics and the poles is stronger at upper levels, so winds increase with height.

Question 44Meteorology (general and dynamic meteorology)

What does a 500 hPa chart primarily depict?

  1. The sea-level pressure
  2. The relative humidity at the surface
  3. The height of the 500 hPa pressure surface Correct answer.
  4. The surface temperature

Explanation

Upper-air charts at 500 hPa show the geopotential height of that pressure surface, along with temperature and wind. Troughs and ridges in the height field steer surface systems.

Question 45Meteorology (general and dynamic meteorology)

In a sounding, the environmental temperature decreases from 25 °C at the surface to 5 °C at 2 km. What is the average environmental lapse rate in that layer?

  1. 2.5 °C per kilometre
  2. 10 °C per kilometre Correct answer.
  3. 5 °C per kilometre
  4. 20 °C per kilometre

Explanation

The temperature change is 20 °C over 2 km, so the lapse rate is 20/2 = 10 °C per kilometre. This is slightly greater than the dry adiabatic rate, making the layer absolutely unstable for unsaturated parcels.

Question 46Meteorology (general and dynamic meteorology)

What is the primary role of condensation nuclei in cloud formation?

  1. They absorb solar radiation and warm the cloud
  2. They prevent the formation of precipitation
  3. They provide surfaces on which water vapour can condense Correct answer.
  4. They increase the saturation vapour pressure

Explanation

Condensation nuclei are tiny particles such as dust, salt, and smoke that lower the energy barrier for condensation. Without them, significant supersaturation would be required for cloud droplets to form.

Question 47Meteorology (general and dynamic meteorology)

What does a positive value of vorticity indicate about the local rotation of a fluid parcel?

  1. Counterclockwise rotation in the horizontal plane Correct answer.
  2. Upward vertical motion
  3. Convergence at the surface
  4. Clockwise rotation in the horizontal plane

Explanation

Vorticity is the curl of the velocity field; by convention, positive relative vorticity in the Northern Hemisphere corresponds to counterclockwise rotation about the local vertical. Cyclonic flow has positive relative vorticity.

Question 48Meteorology (general and dynamic meteorology)

Using the quasi-geostrophic omega equation, what does a region of upper-level positive vorticity advection combined with warm advection imply for vertical motion?

  1. Horizontal convergence only
  2. No vertical motion
  3. Upward motion Correct answer.
  4. Downward motion

Explanation

Positive vorticity advection and warm advection both act as forcing terms that favour ascent in the quasi-geostrophic omega equation. Rising motion supports cloud development and surface pressure falls.

Question 49Meteorology (general and dynamic meteorology)

In the Sutcliffe self-development concept, what relative configuration of upper-level and surface systems favours cyclone deepening?

  1. An upper-level ridge directly over a surface low
  2. A surface high moving under an upper-level ridge
  3. An upper-level trough approaching and overlapping a surface low Correct answer.
  4. An upper-level trough moving away from a surface low

Explanation

Cyclone development is favoured when an upper-level trough with positive vorticity advection moves over a surface low, providing upper-level divergence and pressure falls. The system deepens as the two become vertically aligned.

Question 50Meteorology (general and dynamic meteorology)

What does the Brunt-Väisälä frequency represent in a continuously stratified atmosphere?

  1. The frequency of gravity waves at the surface
  2. The frequency of sound waves
  3. The frequency of buoyancy oscillations of a displaced parcel Correct answer.
  4. The frequency of Rossby waves

Explanation

The Brunt-Väisälä frequency N is the natural frequency at which a vertically displaced parcel oscillates in a stable environment. Its square is proportional to the environmental lapse rate difference from the adiabatic rate.