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Meteorology Flashcards

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1
Q

troposphere

A

hight of the troposphere is 25,000 to 35,000 ft. in the polar regions, and 50,000 to 60,000 ft in the equatorial regions.

most of flying done in this region

all weather found in this region, due to all the moisture being in it.

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2
Q

tropopause

A

the top of the troposphere.
found at 25,000 - 30,000 ft in the polar region, and
55,000 - 65,000 ft in the equator region

decrease in temperature stops at the tropopause

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3
Q

SALR

A

(standard lapse rate) (standard atmosphere)

-2ºC/1000ft

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4
Q

DLAR

A

dry adiabatic lapse rate

-3ºC/1000ft

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5
Q

MALR

A

saturated adiabatic lapse rate (moist adiabatic lapse rate)

-1.5ºC/1000ft

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6
Q

A Stable Atmosphere

A

when environmental lapse rate (ELR) is shallow or even negative.

when lapse rate is negative it is an inversion.

the atmosphere is stable because any air which rises will cool adiabbatically and in doing so will cool more rapidly than the surrounding air which cools at the environmental lapse rate. because rising air cools faster than its surroundings, it will sink back after rising. this is a stable situation

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7
Q

An Unstable Atmosphere

A

when environmental lapse rate (ELR) is steeper than both the dry (DLAR) and wet (MALR) lapse rates.

any air which is forces to rise and cools adiabatically will end up being warmer than the surrounding atmosphere. as a consequence, it will then be lighter than the surrounding air which will then cause it to rise further and in doing so increase the temperature difference between itself and the surrounding air, and so on.

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8
Q

A Conditionally Unstable Atmosphere

A

when the environmental lapse rate (ELR) is somewhere between the dry and adiabatic lapse rates

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9
Q

Environmental Lapse Rate

A

the rate at which the temperature decreases with altitude.

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10
Q

primary causes of weather

A

uneaven heating of the surface of the earth

season variations

latitude variations

diurnal (day/night) variations

different surfaces of the earth absorbing heat differently, i.e. water land

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11
Q

ISA

A

international standard atmosphere

temperature at sea level is 15ºC

ELR is 2ºC/1000ft

pressure at sea level is 29.92 or 1013 hpa (millibars) or 14,69 psi

atmosperic pressure drops by approximately 1” of mercury for every 1000ft

hight of the tropopause is 36,090 ft

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12
Q

convection

A

vertical movement of air

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13
Q

advection

A

the horizontal movement of air

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14
Q

sublimation

A

when a solid changes phase directly to a gas

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15
Q

deposition

A

when a gas changes directly to a solid

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16
Q

coriolis force

A

force which causes the moving air to be deflected to the right (clockwise) in the norther hemisphere and to the left (counterclockwise) in the southern hemisphere

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17
Q

low pressure system

A

air circulates counter clockwise around a low pressure area in the northern hemisphere

forms a trough when they have an elongated shape

lows are usually associated with rising air, and the arrival of cloudy weather and precipitation

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18
Q

high pressure systems

A

air circulates clockwise around a high press system in the northern hemisphere

when it is elongated it formed a ridge

highs are normally associated with defending air, and clear weather with a gentle wind

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19
Q

gust

A

a rapid increaes in a wind speed for a short period of time before retuning to the average speed

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20
Q

squall

A

a rapid increase in wind speed lasting for a minute or longer

squalls may also be caused by a line of thunderstorms which often occur along a front, in which case they are known as line squals

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21
Q

veering

A

when the direction from which the wind blows increases, for example, when the wind changes from a southernly to a south-westerly direction

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22
Q

downburst

A

a very strong localized downdraft from a thunderstorm

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23
Q

high clouds

A

has “cirro” in the name

above 20,000 ft

cirrus: clouds with a streaky fibrous appearance
cirrostratus: a thin layer
cirrocumlus: a small puffy clouds which give the appearance of being flattened

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24
Q

middle cloud

A

has “alto” in the name

between 6,500 - 20,000 ft.

altostratus: uniform layer of cloud
altocumulus: puffy clouds usually patchy

altocumulus castellanus: puffy clouds which grow to a significant height

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25
low clouds
no prefix in name with a base below 6,500 ft stratus: uniform layer of cloud nimbostratus: a dark layer cloud which usually produces continuous precipitation, be it rain sleet snow or freezing rain fractostratus: this is strays cloud with gaps in the layer which gives the appearance of the layered cloud having been torn apart or fractured Cumulus: puffy cods often grouped together.
26
clouds of vertical development
cumulus clouds which grow vertically into towering cumulus or cumulonimbus (thunder) clouds.
27
how to calculate cloud base
take the difference between the temperature and due point spread and divide by 3. eg temp:20º dew point: 5º spread is therefore 15º divide 15 by 3º get 5. therefore, cloud base is at 5000 ft, due to 3º/thousand ft over the temp dew spread.
28
sea breeze
wind coming from the water, due to the land heating during the day
29
land breeze
wind coming from the land, due to the land cooling, and the water acting as a heat sink, retaining heat better
30
chinook
when air containing significant amount of moisture blows toward a mountain range and is forced to rise. in the process, the air cools adiabatically. eventually the moisture will condense given the right circumstances. the air then blows down the other side of the mountain, however it now no longer contains the moisture. as it blows down the other side of the mountain, it warms adiabatically, and due to the fact that it is now dry, will be significantly warmer then when it originally warmed up.
31
mountain waves
lentuclar clouds sever turbulence and wind shear downdrafts altimeter to read incorrectly
32
radiation fog
usually forms on clear nights when there is a gentle wind blowing. the cooling surface cools the air, and as the dew point is reached, visible moisture occurs.
33
advection fog
occurs when air flows from a location where the surface is relatively warm to now which is relatively cool.
34
frontal fog
associated with a front, warm or cold.
35
arctic sea smoke
forms through a process of evaporation and re-condensation. when cold air flows over a relatively warmer water, the water warms the layer of air closest to the water and evaporation. like coffee steam.
36
upslope fog
forms when air which is forced to rise cools adiabatically. if the upslope and moisture content is sufficient then the dew point will be reached and condensation will occur.
37
air masses
body of air with substantially the same properties of temperature humidity stability and tropopause height. continental arctic: dry very cold and stable maritime arctic: moist cold and unstable maritime polar: moist unstable maritime tropical: hoist hot very unstable
38
fronts
a boundary zone between two air masses where a large change of temperature occurs within a relatively short distance. the name of a front is derived from the name of the colder air mass
39
nautical miles to feet
1 nautical mile = 6,000 ft
40
how to estimate the position of a frontal surface
take altitude, convert to miles take frontal slope ratio multiply by converted altitude.
41
occlusion
occurs when a cold front catches up with a warm front. this forces the warm air aloft, forming a trough of warm air aloft, known as a trowel.
42
thunderstorms
form from convective clouds (however, not all convective clouds form thunderstorms) requiers lifting agent turbulence extreem hail icing low visibly low ceiling lightning downdrafts microbursts
43
passing through a cold front
winds will usually veer and increase temperature will start warn, and then drop suddenly. dew point will usually fall presure will decrease steadily, then will level off, and then increase steadily.
44
back
the direction from which the wind blows decreases, for example, the wind changes from an easterly to a north easterly direction.
45
convection
distribution of heat due to daytime heating of the surface of the earth
46
compression
heating by compression | stable air descends into areas of higher pressure at lower altitudes
47
frontal lift
warm less dense air rises over a cold front
48
orographic lift
air is forced aloft over mountains by strong winds
49
convergence
lifting caused by air drawn into the centre of a low
50
adiabatic cooling by expansion
as air expands it will cool air rising into lower pressure will expand and cool, and often condense into a cloud
51
adiabatic heating by compression
as air sinks it will enter an area of higher pressure and the air is compressed and heated
52
stability
biggest determinant as to whether an airmass is stable or unstable is governed by lapse rate. high lapse rate = unstable low lapse rate = stable stable air resists convection while unstable air promotes it.
53
divergence
high pressure pushes air down, and it diverted in every direction once it hits the ground.
54
under reading
altimiter will read lower than your actual altitude (you are higher than indicated). will occur in warmer air, lower pressure air. from high to low, look out below from hot to cold, don't be bold
55
over reading
altimeter will read higher than your actual altitude (you are lower than indicated). will occur in colder higher pressure air from high to low, look out below from hot to cold, don't be bold
56
pressure altitude
the altitude read when set to 29.92 hg
57
density altiude
pressure altitude adjusted for non-standard temperature. used to calculate aircraft performance.
58
true altitude
the indicated altitude corrected for non-standard temperature between the surface and the altitude at which you are flying
59
dominent airmass in canada
winter cA or continental arctic | summer mA maritime arctic
60
arctic airmass
most north
61
polar airmass
just below arctic, vancouver
62
surface analysis charts
``` issued 4 times a day 0000z 0600z 1200z 1800z ```
63
FG
fog
64
PR
partial
65
MI
shallow
66
BC
patches
67
DR
drifting
68
BL
blowing
69
SN
snow
70
DU
dust
71
SA
sand
72
SH
shower
73
RA
rain
74
PL
ice pellets
75
GR
hail
76
GS
snow pellets
77
FR
freezing
78
DZ
drizzle
79
BR
mist
80
FU
smoke
81
HZ
haze
82
VA
volcanic ash
83
TS
thunder storm
84
SS
sand storm
85
DS
dust storm
86
VC
in the vicinity
87
SQ
squalls
88
+FC
tornado or waterspout
89
NS
nimbostratus
90
ST
stratus
91
SC
stratocumulus
92
SF
stratus fractus
93
CU
cumulus
94
CUFRA
cumulus fractus
95
AS
altostratus
96
AC
altocumulus
97
ACC
altocumulus castellanus
98
CI
cirrus
99
CS
cirrostratus
100
CC
cirrocumulus
101
TCU
towering cumulus
102
CB
cumulonimbus
103
GFA
6 charts issued 4 times per day forecasting up to 24,000 ft amended by AIRMET AND SIGMET 2 charts valid at the start of the forecast period 2 charts valid 6 hours into the forecast period 2 charts valid 12 hours into the forecast period ``` issue times: 2330, valid at 0000 0530, valid at 0600 1130, valid at 1200 1730, valid at 1800 ```
104
upper level wind chart winds above 100 knots
subtract 50 from the wind direction and add 100 knots to the speed. in order to display three digit speeds, direction will be +50, in order to signify that 100 needs to be added to the speed.
105
icing
``` can resuce lift by 30%. decreased take off and climb performance reduced stalling angle of attack increased take off and landing speed increased weight reduced controllability airframe vibration ```
106
frost
usually forms overnight from an aircraft parked outside overnight. frozen water vapour accumulates on the airframe
107
clear or glazed ice
transparent associated with the slow freezing of large supercooled water droplets on an airframe. typically encountered in cumulus type clouds in temperatures from 0º to -10º
108
rime ice
rough milky appearance associated with rapid freezing of small supercooled water droplets on an airframe typically encounter in layer stratus type clouds in the temperature of -10º to -20º
109
clean aircraft concept
frost ice or snow myst be removed from critical surfaces of an aircraft prior to flight
110
if your landing with ice
increase approach speed to 20-25% avoid extending flaps fly a stabilized approach do not make abrupt control inputs delay extending the landing gear until the runway is assured be aware of the increased landing distance requirement
111
worst conditions for picking up ice
thin wings high speed throughout a cloud with large droplets high liquid water content high efficiently of ice pick up is bad
112
▲▲▲ solid line with blue triangles
cold front
113
◗◗ solid line with red semicircles
warm front

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