ATSC 113 Top exam questions with completely verified
answers graded A+. 2025/2026
Thermosphere - correct answer T increases w/ height. Beyond this point
is exosphere where air is so thin, does not behave like gas. Avg distance
btw molecules = mean-free path.
Natural Mt. Wave λ depends on - correct answer mean wind speed (M) &
Static stability (S)
High M = High λ
High S = Low λ
Fronde # - correct answer Natural Mt. Wave λ / Mt. Width
Fr << 1 : When low M , high S, Weak Mt. Wave
Fr = 0 : Most violent
Fr >>1 : weak amplitude, high λ
Fr = ∞ : high M, low S, strong turbulent wake behind Mt, but not much Mt
waves.
Boundary layer turbulence - correct answer Turbulence in Atmosphere
boundary later (or PBL).
Often weak-moderate
At night, it's weak but on a sunny day over land, gets stronger through the
day as thermals rise from ground.
Obstacle turbulence - correct answer Created by large obstacles like Mt.
When wind is strong and air near ground is warm (statically
neutral/unstable)
,Fog - correct answer Cloud that touches the ground. Forms when (1)
water added to unsaturated air, (2) when unsaturated air is cooled to dew-
point T (where water vapor starts to condense)
If supercooled tiny liquid water = freezing fog.
Tiny ice crystals = ice fog.
Cool air (dense) flows downhill = valley fog
Night w/ much cloud cover prevents ground cooling -> no fog. It is an
obscuration reducing horizontal vis.
Science Joke - correct answer 2 men walk up to a bar, the first asks for a
glass of H2O, the second asks for a glass of H2O too. The second man
died.
UBC Joke - correct answer What is common between UBC and SFU
students? They both applied to UBC.
Types of fog - correct answer Radiation fog: cool ground on clear, calm
night cools air
Advection fog: humid air blows over cold surface, air T -> dew-point T
(water vapors start to condense), can form well-defined front edges.
Upslope fog: wind blows against hill -> adiabatic cooling as it rises -> fog.
Precipitation/Frontal fog: formed by moisture via evap of warm rain, creates
fractus clouds.
Arctic sea smoke/ Steam fog: forms when cold air moves over warm
lake/ocean during early winter. Humid air mixes w/ cold air above ->
mixture becomes saturated.
,League of Legends Joke - correct answer Q: Why is Twisted Fate an
illegal immigrant?
A: Because he doesn't have a green card!
Obscuration - correct answer 1. Mist: small precipitation particles gently
falling.
2. Smoke
3. Volcanic ash: microscopic sharp rocks settling slowly, very abrasive, may
cause St. Elmo's fire.
4.Sand: Similar abrasive effect as volcanic ash.
5. Haze: consists of microscopic liq water around hygroscopic pollutant,
become larger with rel. Humidity.
6. Spray: tiny droplets of sea water caused by breaking waves.
7. Dust: consists of a variety of microscopic solid.
8. Snow: a blizzard is blowing snow with decreased vis and fast wind (may
lead to white out), listed as a weather element, not obscuration.
9. Rain: you may fly around, not listed as obscuration.
Armstrong altitude - correct answer Above 62000 ft, boiling T decreases
to where your bodily fluid starts boils, need a pressurized suit.
Density Altitude - correct answer Pressure altitude corrected for different
temperature, lower density leads to longer runway for take-off and landing,
slower climbing, not being able to climb as high.
Convective Boundary Layer - correct answer Air rises due to heating from
sun. Diameter similar to depth, cumulus cloud may form w/ enough
moisture. If these cumulus aligned in a row -> cloud streets.
, Anabatic winds - correct answer Air movement when thermals follow the
slope and rise vertically above ridge top. If humid enough -> anabatic
cumulus.
Sea level pressure/ mean sea level pressure - correct answer Surface
pressure if it was at sea level.
Ridges & Troughs of Pressure pattern - correct answer Ridges: rel. High
P that extends from high P centres.
Troughs: lines of propagation of low P.
High P system - correct answer aka anticyclone, associated w/ dry, clear
skies, less precipitation
Flat light - correct answer when high clouds diffuse light & snow surface
has no definition (low P approaching)
P-level map - correct answer Sea leve = 100kpa
1500m = 85.0kpa
3000m = 70.0kpa
Dry vs wet adiabatic condition - correct answer Dry: T decreases at
10C/km (9.8), <80% rel. Humidity, in the daytime during spring/ afternoon
on sunny winter days.
Wet: T decrease slower 6C/km, >80% rel. Humidty.
Stable conditions - correct answer Temperature decreases more slowly or
even increases w/ height.
answers graded A+. 2025/2026
Thermosphere - correct answer T increases w/ height. Beyond this point
is exosphere where air is so thin, does not behave like gas. Avg distance
btw molecules = mean-free path.
Natural Mt. Wave λ depends on - correct answer mean wind speed (M) &
Static stability (S)
High M = High λ
High S = Low λ
Fronde # - correct answer Natural Mt. Wave λ / Mt. Width
Fr << 1 : When low M , high S, Weak Mt. Wave
Fr = 0 : Most violent
Fr >>1 : weak amplitude, high λ
Fr = ∞ : high M, low S, strong turbulent wake behind Mt, but not much Mt
waves.
Boundary layer turbulence - correct answer Turbulence in Atmosphere
boundary later (or PBL).
Often weak-moderate
At night, it's weak but on a sunny day over land, gets stronger through the
day as thermals rise from ground.
Obstacle turbulence - correct answer Created by large obstacles like Mt.
When wind is strong and air near ground is warm (statically
neutral/unstable)
,Fog - correct answer Cloud that touches the ground. Forms when (1)
water added to unsaturated air, (2) when unsaturated air is cooled to dew-
point T (where water vapor starts to condense)
If supercooled tiny liquid water = freezing fog.
Tiny ice crystals = ice fog.
Cool air (dense) flows downhill = valley fog
Night w/ much cloud cover prevents ground cooling -> no fog. It is an
obscuration reducing horizontal vis.
Science Joke - correct answer 2 men walk up to a bar, the first asks for a
glass of H2O, the second asks for a glass of H2O too. The second man
died.
UBC Joke - correct answer What is common between UBC and SFU
students? They both applied to UBC.
Types of fog - correct answer Radiation fog: cool ground on clear, calm
night cools air
Advection fog: humid air blows over cold surface, air T -> dew-point T
(water vapors start to condense), can form well-defined front edges.
Upslope fog: wind blows against hill -> adiabatic cooling as it rises -> fog.
Precipitation/Frontal fog: formed by moisture via evap of warm rain, creates
fractus clouds.
Arctic sea smoke/ Steam fog: forms when cold air moves over warm
lake/ocean during early winter. Humid air mixes w/ cold air above ->
mixture becomes saturated.
,League of Legends Joke - correct answer Q: Why is Twisted Fate an
illegal immigrant?
A: Because he doesn't have a green card!
Obscuration - correct answer 1. Mist: small precipitation particles gently
falling.
2. Smoke
3. Volcanic ash: microscopic sharp rocks settling slowly, very abrasive, may
cause St. Elmo's fire.
4.Sand: Similar abrasive effect as volcanic ash.
5. Haze: consists of microscopic liq water around hygroscopic pollutant,
become larger with rel. Humidity.
6. Spray: tiny droplets of sea water caused by breaking waves.
7. Dust: consists of a variety of microscopic solid.
8. Snow: a blizzard is blowing snow with decreased vis and fast wind (may
lead to white out), listed as a weather element, not obscuration.
9. Rain: you may fly around, not listed as obscuration.
Armstrong altitude - correct answer Above 62000 ft, boiling T decreases
to where your bodily fluid starts boils, need a pressurized suit.
Density Altitude - correct answer Pressure altitude corrected for different
temperature, lower density leads to longer runway for take-off and landing,
slower climbing, not being able to climb as high.
Convective Boundary Layer - correct answer Air rises due to heating from
sun. Diameter similar to depth, cumulus cloud may form w/ enough
moisture. If these cumulus aligned in a row -> cloud streets.
, Anabatic winds - correct answer Air movement when thermals follow the
slope and rise vertically above ridge top. If humid enough -> anabatic
cumulus.
Sea level pressure/ mean sea level pressure - correct answer Surface
pressure if it was at sea level.
Ridges & Troughs of Pressure pattern - correct answer Ridges: rel. High
P that extends from high P centres.
Troughs: lines of propagation of low P.
High P system - correct answer aka anticyclone, associated w/ dry, clear
skies, less precipitation
Flat light - correct answer when high clouds diffuse light & snow surface
has no definition (low P approaching)
P-level map - correct answer Sea leve = 100kpa
1500m = 85.0kpa
3000m = 70.0kpa
Dry vs wet adiabatic condition - correct answer Dry: T decreases at
10C/km (9.8), <80% rel. Humidity, in the daytime during spring/ afternoon
on sunny winter days.
Wet: T decrease slower 6C/km, >80% rel. Humidty.
Stable conditions - correct answer Temperature decreases more slowly or
even increases w/ height.
