Atsc 113 Knowledge test Exam Toolkit Questions and
Verified solution 2025/2026
Mountain waves - correct answer - vertical oscillations of the air as it flows
over mountains.
- these strong winds can destroy houses and can roll trucks, and can cause
airplanes to crash
Updrafts and soaring - correct answer soaring
- without updrafts the gliders will gently descend down toward the ground
= any weather phenomenon that provides smooth reliable updrafts is usually
welcomed by soaring pilots
- mountain waves and anabatic winds along mountain slopes cause long
bands of updrafts
- smaller, localized updrafts are found within thermals but sometimes these
thermals are aligned into rows that enable long distance soaring
= the clouds at the top of these thermal rows are called cloud streets
Mountain waves and soaring - correct answer - when the wind moves air of
correct static stability over a mountain range, the air to the lee (downwind) of
the mountain can oscillate up and down as a mountain wave
- one portion of each wave has an updraft, and the other portion has a
downdraft
- the locations of the crests and troughs (and also of the updraft regions) shifts
upwind with increasing altitude
- as a sailplane soars to higher altitudes in mountain waves, the pilot should
try to gradually move upwind (toward the mountain location) in order to stay in
the maximum updraft.
,Thermals and soaring - correct answer - when sunlight heats the ground, the
ground warms the air touching it and warm air rises as thermals
- as the thermals gently drift downwind, birds and soaring pilots stay with the
thermal to get the maximum lift
- if the larger scale winds are relatively light or calm, then the thermals are
coherent (the updraft is well defined and vertically aligned or slightly tilted)
over most of the depth of the thermal
- between the thermals are downdrafts of return flow
- thermals are typically shallow (100 m deep) in the early morning, and can be
as deep as 1 to 4 km by mid afternoon, depending on the location, the
dryness and color of the soil, and the intensity of the sunshine.
= layer of thermals is called the convective boundary layer
Convective boundary layer - correct answer - convective boundary layer is
often more polluted than the clearer air above, allowing laser radarsto see the
boundary-layer thermals by the air pollutants carried by the air
- thermals have larger diameters later in the day compared to in the morning.
Cloud streets - correct answer - if there is enough moisture in the air, then a
cumulus cloud might form in the top portion of each thermal
- these clouds help the sailplane pilot locate the updraft regions
- with a moderate wind, the thermals could be aligned into rows that are
approximately parallel to the wind direction
- if there are cumulus clouds at the tops of these rows of thermals, then the
rows of clouds are called cloud streets
,- cloud streets and the updrafts under them allow sail-plane pilots to soar for
long horizontal distances under those clouds
Anabatic winds and anabatic cumulus clouds - correct answer - warm
updrafts along the mountain slopes are are called anabatic winds or anabatic
circulations
- if the air has sufficient humidity, then cumulus clouds might form at the tops
of these rising thermals
- these are called anabatic cumulus and are found along the mountain
ridgelines
- thermal updrafts = turbulent and irregular
Valley wind - correct answer - associated with the anabatic cross-valley
circulations is an along-valley wind blowing very gently upstream during the
daytime
- called a valley wind.
Standard atmosphere - correct answer - the average variation of air pressure
(P), temperature (T), and density (ρ) with altitude is called the standard
atmosphere
Temperature - correct answer - temperature does not decrease smoothly at
all altitudes
- decreases smoothly at first with increasing altitude in the bottom of the
atmosphere
, Troposphere - correct answer - almost all of our weather occur in the
troposphere which is the bottom part of the atmosphere where temperature
decreases roughly linearly (as a straight line) with height
- the average temperature around the world at sea level is about 15°C , due to
its contact with the sun-heated earth surface. At the 11 km top of the
troposphere the temperature is about -56°C
- the top of the troposphere is called the tropopause (nickname is "trope")
- on average, the troposphere is thinner during winter and thinner near the
poles
Stratosphere - correct answer - the top of the stratosphere is called the
stratopause
- in the stratosphere temp does not decrease with increasing height
- so the temp is constant (isothermal) at first, and then gets warmer as you
approach the stratopause
- stratopause is warm because of the "good" ozone layer there, which gets hot
when it absorbs the harmful ultraviolet rays from the sun
Many modern commercial aircraft fly in the lower stratosphere to get above
most of the storms and weather that are in the troposphere
Mesosphere - correct answer - where temperature again decreases with
increasing altitude
- the top of the mesosphere is called the mesopause.
Verified solution 2025/2026
Mountain waves - correct answer - vertical oscillations of the air as it flows
over mountains.
- these strong winds can destroy houses and can roll trucks, and can cause
airplanes to crash
Updrafts and soaring - correct answer soaring
- without updrafts the gliders will gently descend down toward the ground
= any weather phenomenon that provides smooth reliable updrafts is usually
welcomed by soaring pilots
- mountain waves and anabatic winds along mountain slopes cause long
bands of updrafts
- smaller, localized updrafts are found within thermals but sometimes these
thermals are aligned into rows that enable long distance soaring
= the clouds at the top of these thermal rows are called cloud streets
Mountain waves and soaring - correct answer - when the wind moves air of
correct static stability over a mountain range, the air to the lee (downwind) of
the mountain can oscillate up and down as a mountain wave
- one portion of each wave has an updraft, and the other portion has a
downdraft
- the locations of the crests and troughs (and also of the updraft regions) shifts
upwind with increasing altitude
- as a sailplane soars to higher altitudes in mountain waves, the pilot should
try to gradually move upwind (toward the mountain location) in order to stay in
the maximum updraft.
,Thermals and soaring - correct answer - when sunlight heats the ground, the
ground warms the air touching it and warm air rises as thermals
- as the thermals gently drift downwind, birds and soaring pilots stay with the
thermal to get the maximum lift
- if the larger scale winds are relatively light or calm, then the thermals are
coherent (the updraft is well defined and vertically aligned or slightly tilted)
over most of the depth of the thermal
- between the thermals are downdrafts of return flow
- thermals are typically shallow (100 m deep) in the early morning, and can be
as deep as 1 to 4 km by mid afternoon, depending on the location, the
dryness and color of the soil, and the intensity of the sunshine.
= layer of thermals is called the convective boundary layer
Convective boundary layer - correct answer - convective boundary layer is
often more polluted than the clearer air above, allowing laser radarsto see the
boundary-layer thermals by the air pollutants carried by the air
- thermals have larger diameters later in the day compared to in the morning.
Cloud streets - correct answer - if there is enough moisture in the air, then a
cumulus cloud might form in the top portion of each thermal
- these clouds help the sailplane pilot locate the updraft regions
- with a moderate wind, the thermals could be aligned into rows that are
approximately parallel to the wind direction
- if there are cumulus clouds at the tops of these rows of thermals, then the
rows of clouds are called cloud streets
,- cloud streets and the updrafts under them allow sail-plane pilots to soar for
long horizontal distances under those clouds
Anabatic winds and anabatic cumulus clouds - correct answer - warm
updrafts along the mountain slopes are are called anabatic winds or anabatic
circulations
- if the air has sufficient humidity, then cumulus clouds might form at the tops
of these rising thermals
- these are called anabatic cumulus and are found along the mountain
ridgelines
- thermal updrafts = turbulent and irregular
Valley wind - correct answer - associated with the anabatic cross-valley
circulations is an along-valley wind blowing very gently upstream during the
daytime
- called a valley wind.
Standard atmosphere - correct answer - the average variation of air pressure
(P), temperature (T), and density (ρ) with altitude is called the standard
atmosphere
Temperature - correct answer - temperature does not decrease smoothly at
all altitudes
- decreases smoothly at first with increasing altitude in the bottom of the
atmosphere
, Troposphere - correct answer - almost all of our weather occur in the
troposphere which is the bottom part of the atmosphere where temperature
decreases roughly linearly (as a straight line) with height
- the average temperature around the world at sea level is about 15°C , due to
its contact with the sun-heated earth surface. At the 11 km top of the
troposphere the temperature is about -56°C
- the top of the troposphere is called the tropopause (nickname is "trope")
- on average, the troposphere is thinner during winter and thinner near the
poles
Stratosphere - correct answer - the top of the stratosphere is called the
stratopause
- in the stratosphere temp does not decrease with increasing height
- so the temp is constant (isothermal) at first, and then gets warmer as you
approach the stratopause
- stratopause is warm because of the "good" ozone layer there, which gets hot
when it absorbs the harmful ultraviolet rays from the sun
Many modern commercial aircraft fly in the lower stratosphere to get above
most of the storms and weather that are in the troposphere
Mesosphere - correct answer - where temperature again decreases with
increasing altitude
- the top of the mesosphere is called the mesopause.
