Meteorology Flashcards
1
Q
Name the structures of the atmosphere
A
Trophosphere
Tropopause
Ozone layer
Stratosphere
Stratopause
Mesosphere
Mesopause
Thermosphere
2
Q
What does ISA stand for?
A
International Standard Atmosphere
3
Q
What height is ISA temperature fixed after?
A
36,090 ft
4
Q
What is the ISA fixed temperature after 36,090ft?
A
-56.5 C
5
Q
What is the ISA sea level temperature?
A
+15C
6
Q
What is the temperature lapse rate?
A
The rate at which temperature changes with height in the Atmosphere
7
Q
What is the temperature lapse rate in Troposphere?
A
1.98C/100ft (until 36,090ft is reached)
(2C/1000ft for calculations)
8
Q
How is the lower part of the troposphere heated?
A
Earths surface
9
Q
What is the composition of the atmosphere?
A
78% Nitrogen
21% Oxygen
1% Other gases
10
Q
What makes up the 1% other gases in the atmosphere?
A
Argon
Carbon Dioxide
Hydrogen
Ozone (O3)
Carbon Monoxide - emitted by volcanos
11
Q
What does carbon dioxide do in the atmosphere?
A
Acts as a blanket (keeps earth warm)
By reflecting long wave radiation
12
Q
Water vapour makes up what % of the atmospheres volume at lower levels?
A
4%
13
Q
1/2 of water vapours mass is found below what measurement?
A
1.5km
14
Q
How much water vapour is contained in the troposphere?
A
99%
15
Q
The amount of water vapour in the air depends on what?
A
Temperature
Warm air can hold more vapour than cold air
Cold air has a lower carrying capacity
16
Q
In the Tropopause what no longer decreases with height?
A
Temperature
17
Q
The height of the tropopause depends on what?
A
Temperature of the earths surface
18
Q
What is the height and temperature of the Tropopause?
A
36,090ft and -56.5C
Up to 60,000-65,000 in warmer countries
19
Q
The warmer it is the … the tropopause
The colder it is the … the tropopause
A
Higher
Lower
20
Q
Heights and Temperature of polar and equatorial tropopause
A
Polar 8 (winter)-10km(summer) (-40C/-50C) - lower due to angle relative to the sun
16-18km high (-70C/-90C)
21
Q
Where is the jet stream?
A
Just below the tropopause
22
Q
Whats the relationship between the Tropopause and Latitude?
A
Changes in height due to the relative tilt, changes of planet (relative to the sun)
23
Q
Why is the stratosphere a good or bad place to fly?
A
Cloud formation is rare
Above hazards of troposphere (E.g CB)
Turbulence is still possible
24
Q
What height is the temperature constant to in the stratosphere, until the Ozone layer starts?
A
Approximately 65,000ft
25
What does the Ozone layer do?
Absorb short wave radiation (UV)
26
What's the relationship between Ozone and the stratosphere
Ozone layer is 90% within the stratosphere
Ozone is responsible for the temperature increase within the stratosphere
27
Ozone negatives
Extremely corrosive gas
Can impact cabin air quality at high altitudes, possible respiratory problems - smells like chlorine
28
InHg and mmHG meaning?
Inches/millimetres of Mercury
29
Relationship with altitude of pressure and density?
Pressure and density decrease with altitude
(pressure due to less air resistance)
30
ISA Temperature Calculation
ISA Temp = 15-2 x altitude (ft) / 1000
31
What is ISA deviation?
ISA temp compared to actual conditions
If its warmer than ISA conditions, deviation is (+)
If its colder than ISA conditions, deviation is (-)
32
What does hPA stand for?
Hectopascal
33
What is the ISA static pressure? (hPA)
1013.25
(1013 in calculations)
34
What is the pressure change rate?
1hPA/30ft
1hPA/9m near sea level
35
What does AMSL mean?
Above mean sea level
36
ISA density comparison from AMSL to 22,000ft and 40,000ft
22,000 is approx 50% compared to AMSL
40,000 is approx 25% compared to AMSL
37
Pressure is ... of surface value at 18,000ft
50%
38
As temperature increases, density...
Decreases
39
As altitude increases, temperature
Decreases
40
What does ICAO stand for?
International Civil Aviation Organisation (ICAO)
41
TAF
Terminal Area Forecast
(RUMOUR)
42
METAR
Meteorological Aerodrome Report
(TRUTH)
43
What is an ASHTAM
Provides info on the status activity of a volcano when there's been/(going to be) a change in its activity
44
45
What is WAFC?
World Area Forecast Centre
Located in London/Washington
46
What do WAFC do?
Issue significant weather charts every 6-9h
They report
~Upper winds/temp/humidity
Tropopause height/temp
~Areas of significant weather - (CB, icing, turbulence)
47
What are Meteorological Offices? and what do they do?
Located all over the world (UK office = Exeter)
Issue TAF every 3-6h, valid between 6 and 30 hours
Issue low level area forecast every 6h if required
48
What do Meteorological stations do?
TRUE REPORT
Aerodrome based
Issue METARS every 30-60mins
Issue SPECI as required - significant change in weather
Issue TREND/LANDING forecast - valid for 2 hours
Issue SNOWTAM - snow/slush/ice warning - valid up to 8h
Issue AERODROME WARNING (ADW) - warning of conditions affecting aircraft, vehicles and facilities - everyone
49
What is MWO and what do they do?
Meteorological Watch Offices
Issue weather warmings:
~SIGMET, upper level - 4/6h
~AIRMET, low level below FL100/150 - 4h
~ASHTAM, volcanic activity/ash clouds - 24h (6h if active
50
What does VAA and TCA stand for?
Volcanic Advisory
Tropical Cyclone Advisors
51
What is a SIGMET?
Warning of dangerous meteorological conditions - from MWO
Include
Thunderstorms
Tropical Cyclone
Severe Turbulence
Servere Icing
Severe mountain waves
Heaving sand/dust storm
Volcanic ash/radioactive cloud (VA & RDOACT)
52
53
SIGMET timeline
Air report > ATC > MWO > WAFC's ( di sect SIGMET)
WAFC's >MWO > ATC > Aircraft behind
54
55
OKTA's Sky Coverage
8th Sky
SKC - Sky Clear
FEW - 1-2
SCT - 3-4
BKN - 5-7
OVC - 8
56
57
Airbourne weather radar controls...
On/Off/Stby
Gain (sensitivity)
Tilt (up/down)
Mode Switch (Wx,Ground,Turb)
Range 40-320nm
58
When must your Airborne weather radar be turned off?
At/near the terminal
59
What does the Airborne Weather Radar do when on stby?
Warms up - ready for use
60
Label the weather radar and state different colours
61
What doesnt the Weather radar pick up?
CAT
Clear Air Turbulence
62
Label the different weather systems on the radar
63
What is the blind alley affect?
Shadowing
Black areas don't always mean no threat
~ Radar can be blocked from weather systems so cannot see as far as it normally can
64
Why do you have to change the gain on the Weather radar?
For the range, so you have to increase/decrease the sensitivity
65
What is a ground based weather radar?
Detects location/movement of water droplets
66
How does the ground based weather radar work?
Sends out pulses of microwave energy
Listens for returning signals from target (droplets)
67
What are the two main types of detectors?
Visible Imagery
Infared Imagery
68
Satellite Visible imagery
Reflects sunlight
Useful for seeing cloud patterns
Only during daylight hours
Better detecting low cloud/fog than IR
69
Satellite Infrared imagery
Day/Night
Colour - cloud temps
High/cold clouds = white
Low clouds = dark
70
71
What are the two types of Satellite Observations?
Orbit type
Detector type
72
What is a Geo-Stationary Satellite?
It focuses on one particular area
73
How far is the Geo-Stationary Satellite away from earth?
35786km
74
Geo-Stationary Satellite Positives
~Good overall picture
~Tracking a system
~Monitoring of the atmosphere
75
Geo-Stationary Satellite Negatives
~Poor Resolution
~Not good at seeing small changes
76
What is the Polar Orbiting Satellite?
Orbits from pole to pole (N>S)
~ Have to wait to obersve certain area once satellite comes bak round
77
How often does the Polar Orbiting Satellite orbit each day?
Twice a day
78
Polar Orbiting Satellite Positives
~Sees small picture
~Better resolution
~Good tracking of small features
~Flexible Orbit
79
Polar Orbiting Satellite Negatives
~Narrow Range
~Not Good at tracking a storm movement
80
How far is the Polar Orbiting Satellite away from earth?
850km
81
What is an Atmospheric Motion Vector?
Detects motion of wind
~ Shows jet streams
82
What is Temperature?
Avergage kinetic energy of the atoms or molecules
83
Celcius Equation
84
Kelvin Equation
85
Fahrenheit Equation
86
What piece of equipment do you use to measure temperature and how does it work?
Old Style Thermograph
Plots temperature change with time or height
87
How to measure surface air temperature?
Stevenson Screen
~ Situated 1.2m off the ground to avoid ground heat interference
~ Measures surface temp and humidity
88
How accurate is the Stevenson Screen?
95%
89
How to measure Upper Air Temperature?
Radiosonde
90
What three sets of data does a radiosonde record?
Temperature
Pressure
Humidity
91
How does a Radiosonde work?
Rises to 115,000ft
Records data every 1.3s during climb (every second but takes 0.3s to get data to ground)
Transmitted by VHF radio
92
What is an inversion?
Temperature increase with height
93
What is Radiation?
Transmission of energy
94
What does short wave insolation do?
Penetrates through the atmosphere
95
What does long wave terrestrial radiation do?
Radiation is absorbed by the atmosphere
96
Relationship between oceans and radiation
Absorb/release radiation slowly (heat sink)
97
Weather tends to be ... over bodies of water
Weather tends to ... over land
Calmer
Amplified - heat energy gives the weather more energy
98
What is insolation?
The energy from the sun that reaches the earth in short waves.
99
Earths axis of rotation
23.5 degrees
100
What is the shortest night/longest day called?
Solstice on the 21st June
101
What is the shortest day/longest night called?
Solstice on the 22nd December
102
What does Aphelion mean and when is it?
Point furthest away from sun
4th July
103
Aphelion distance
152 million km
104
What does Perihelion mean and when is it?
Point closest to sun
4th January
105
Perihelion distance
147 million km
106
What does Equinox 23rd September mean?
Equal night (Autumn)
107
What does Equinox 21st March mean?
Spring
108
What does ITCZ stand for?
Inter Tropical Convergence Zone (ITCZ)
109
Why is there bad storms in southern hemisphere summer?
More sea land
Ocean takes time to heat/cool so gradually emits LW radiation which gives weather systems more energy
110
What is the ITCZ?
Band of low pressure which generally lies near the equator
Location pf maximum heating on earth
111
What does ISO mean
Equal Layer
112
Solar radiation reaching the earths surface depends on... and why?
ARS
Absorption - Ozone layer and water vapour
Reflection - Tops of clouds & earth
Scattering - Particles in atmosphere
85% REACHES THE EARTHS SURAFCE
113
Water requires ... of energy to warm up but ... the energy
Sand warms up ... ... bar cools down ...
A lot
Very Quickly
Quickly
114
What is Albedo?
Dimensionless number referring to reflectivity
Less Albedo = Less reflectivity
115
Earths Albedo (average)
31%
116
Fresh snow Albedo
80-95%
117
Forest Albedo
10-20%
118
Crops Albedo
10-25%
119
Grass Albedo
25-30%
120
Asphalt Albedo
5-10%
Absorbs 95% of radiation
121
Dark Roof Albedo
8-18%
122
Light Roof Albedo
35-50%
123
Large water surface Albedo
10-60%
124
Moon Albedo
8-18%
125
Conduction is...
Engery transfer by contact
126
Convection is...
Energy transfer by vertical movement of air
127
Advection Is...
Energy transfer by horizontal movement of air
128
Release of latent heat is...
Energy transfer when condensation takes place
129
Radiation is...
Energy transfer by absorption of long wave radiation
130
Turbulence is...
Energy transfer by mixing of air caused by turbulence
131
What is a Diurnal Variation and what effects it?
Variation of the surface temperature over a 24h period
~ Water (oceans)
~Wind
~Clouds
132
How is the Diurnal Variation measured?
Amount of energy received from the sun vs amount of energy released from the earth
133
What do clouds to do Diurnal Variation?
Reduces daily variation
Clouds reflect radiation and equalise temperatures
134
Diurnal Variation - cloud (Graph)
135
What does wind do to Diurnal Variation?
Decreases DV
As it decreases temperature
136
Diurnal Variation - wind (Graph)
137
What does density do to aircraft performance?
Reduces performance
Risk impact with terrain/obstacles due to loss of climb
Risk exceeding available runway distance
138
What is Air Density?
Mass of the molecules in a given volume
139
As temperature increases, density ...
Decreases
Density is inversely proportional to temperature
140
As pressure increases, density
Increases
Density is proportional to pressure
141
When pressure increases (near surface), air is compressed, volume ... and density ...
Decreases
Increases
142
Pressure ... or ... in temperature, performance improves
Pressure ... or ... in temperature, performance reduces
Increase
Decrease
Decrease
Increase
143
Density of moist air is ... than dry air
Less
144
What are isobars?
Lines of equal pressure
145
What direction does airflow travel in Nth Hemisphere?
Anti Clockwise
146
What direction does airflow travel in Sth Hemisphere?
Clockwise
147
What is subsiding air?
Falling air
148
What is converging air?
Air moving towards each other
149
What is Convecting air?
Air moving upwards
150
What is diverging air?
Air moving away from each other
151
What happens when cold and warm air collide with one another?
Warm air passes over the cold air
Creates a low pressure system as air ay the surface is pulled upwards
152
What is an Isobar?
Line of equal pressure
153
What is a col?
Area in-between 2 highs and 2 lows
Light winds
Fog in winter/TS in summer
154
What do isobars close together represent?
High winds
155
What causes depressions?
High level divergance (Jetstreams)
Sea level pressure drops and forms depression
Good vis > pollutants sucked upwards
156
High level convergence is also know as...
Anticyclone
157
Cold fronts typically move ...
Warm fronts typically move ...
Downwards
Upwards
158
What is a secondary depression?
From within the circulation of primary depression
Rotates within the main system
159
Cold core low : common for a ... front depression
Warm core low : more likely in ... depressions
Polar
Tropical
160
Label the Highs/Lows
A) Cold Core Low
B) Warm Core Low
C) Cold Core High
D) Warm Core High
161
When can Thermal lows occur?
Occur when cold air over continents, moves over warmer seas in winter
162
What is an Orographic Low/Depressions (Lee Low)
Substancial air blowing against mountain
Wind side = air compressed
Lee Low side = suction effect (convergence)
Can create heavy showers, CB's, TCU's, Wind Shear
This is only if parcel is warm, if not the air falls back down to the ground
163
How are Anticyclone (High) formed?
High level of convergence
Leads to subsiding air
164
Cold Anticyclones
Cold surface temperatures makes lower troposphere cold and dense
165
Warm Anticyclones
Excess air in upper troposphere
Pressure lève;s bulge up at both upper/lower levels
166
What is a blocking high?
Blocks further eastward movement of systems
Very intense weather fir a long period
167
State of change cycle...
168
What is a condensation Nuclei?
Essential for starting the binding process (vapour to liquid droplets) - allows condensation to begin as it binds onto the particle
E.g Dust, Salt
169
What are the cooling processes when latent heat is absorbed?
Melting and evaporation
170
What are the warming processes when latent heat is released?
Freezing and Condensation
171
What is humidity and how is it measured?
Amount of water vapour in the air
Hygrometer
172
Two types of humidity include...
Absolute Humidity
Relative Humidity (most common)
173
What's it called when water is holding the maximum amount of water vapour?
Saturated
174
Relationship between air temperature and water vapour
Warmer the air, thew more more content it can hold due to higher energy so can except more
175
Do humidity levels vary?
Average humidity levels vary according to temperature/climate
176
What is absolute Humidty
Total amount of water vapour present in a given volume, measured in g/m^2
177
Absolute humidity
Air temp vs 100% saturation figures
0 C = 3.8g/Kg
10 C = 7.6g/Kg
20 C = 14.6g/Kg
30 C = 26.6g/Kg
178
WVP stands for?
Water Vapour Pressure - pressure each water vapour molecule exerts
Similar to Absolute Humidity
179
Saturation value is ... over ice than over ... Why?
Less
Liquid
Bonds are closer (tight), harder for molecules to leave ice than a liquid
180
Relative Humidity Word equation/def
Mass of water vapour in a volume of air
_________________________________________
Maximum mass of water vapour the volume of air can hold
E.g 10g/M^3 / 20g/M^3 = 50%
181
What is a dew Point?
Level at which droplets condense
182
When does RH increase?
Decraese in temperature
Inverse relationship
183
Diurnal Variation, RH graph
184
RH calculation equation
RH% = 100 - (5 x (T-TD)
T = Ambient pressure
TD = Dew Point
185
Initial Causes of vertical motion include...
Convection
Orographic lift
Convergence
Surface mixing
Frontal lift
186
Convection lift picture
187
Orographic lift picture
188
Convergence lift picture
189
Surface mixing picture
190
Frontal lift picture
191
Dependant on ELR, the environment can be be categorised as ...
Stable
Neutral
Unstable
192
What does a stable environment mean?
Parcel of air returns to original position
193
What does a neutral environment mean?
No tendency to return to original position or move further away
194
What does an unstable environment mean?
Parcel of air moves further away (from original position)
195
What is the Enviromental Lapse Rate (ELR)?
Rate at which temperature changes with height
1.98C/1000ft or 2C/1000ft for calls
Ranges between 0.6C and 4C/1000ft in actual environment
196
How is ELR measured?
Radiosonde
197
Adiabatic Cooling is...
Parcel of air rises, enters a low pressure area
Parcel of air will expand > Results in loss of temperature
THINK BIKE PUMP
198
Adiabatic Warming is...
Parcel of air sinks, enters a high pressure area
Parcel of air will compress, resulting in an increase in temperature
THINK BIKE PUMP
199
What is DALR?
Dry Adiabatic Lapse Rate (DALR)
200
DALR def and formula
Provided water coupe does not condensate when it rises, the parcel of air cools at 3C/1000ft
201
What is SALR?
Saturated Adiabatic Lapse Rate (SALR)
202
SALR def and formula
Air in which condensation has occurred and cools at a rate of 1.8C/1000ft
(CLOUD FORMATION)
203
Difference between QNH and QFE
QNH = MSL pressure
QFE = Airfield pressure
204
What is height?
Vertical distance of an a/c, level or point with respect to specified datum
Distance between alt/FL and aerodrome (elevation)
205
Altitude is...
Vertical distance of an a/c with respect to MSL
206
Elevation is...
Vertical distance above MSL
207
True Alt is...
Actual vertical distance above MSL
208
indicated Alt is...
Alt shown on a/c altimeter when its set to local pressure at aerodrome
209
Pressure to alt relationship
30ft per 1hPA - up to 18,000ft
50ft per 1hPA - above 18,000ft
210
What is pressure alt?
Height above standard datum plane, theoretical level where height go the atmosphere is 1013.25hPA
211
SPS is...
Standard Pressure Setting (SPS)
212
If you wind on pressure (on altimeter), you...
Wind on height
213
If you wind off pressure (on altimeter), you...
Wind off height
214
How are VFR/IFR flight levels determined?
By magnetic track
215
Flight Levels, semi circular rule
216
VFR
a/c tracks between what degrees...
000-179 degrees, FL ODD number (thousand) +500ft
180-359 degrees, FL EVEN number (thousand) +500ft
217
IFR
a/c tracks between
000-179 degrees, FL ODD number (thousand)
180-359 degrees, FL EVEN number (thousand)
218
Transition ALt is...
Specified alt where you can change from QNH to standard when climbing
219
When do you change QNH/FL
On climb
Above transition alt - a/c reference to standard pressure (1013hPA) - FL
Below trans alt - a/c reference to altitude (QNH), not FL
220
Transition level is...
Changes with pressure
Its the first available flight level after trans alt
221
Transition layer is...
Inbetween transition alt and transition level
222
What is there transition layers minimum alt?
1000ft
223
Example of Trans alt, FL and Trans Lvl
224
Why do you have to go tot her next FL if the trans layer is less layer 1000ft?
Unsafe, minimum alt for the layer is 1000ft, otherwise you may fly into other a/c
225
What does TEC stand for?
Temperature Error Correction (TEC)
226
TEC equation
TEC = (Height/1000) x 4 (degrees celsius) x ISA dev
227
Where is TEC considered for?
Layer between the ground (station) and the a/c position
228
TEC rules (warmer/colder ISA)
229
Working out Indicated Alt to True Alt
230
Working out True Alt to Indicated Alt
True height
ISA dev
TEC calc
Determination of indicated alt
Determination of FL via pressure alt
231
How to remember flying from low and high temps
High to low
~look out below (decrease in alt)
Low to high
~high in the sky
