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Meteorology Flashcards

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
Q

low clouds

A

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.

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26
Q

clouds of vertical development

A

cumulus clouds which grow vertically into towering cumulus or cumulonimbus (thunder) clouds.

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27
Q

how to calculate cloud base

A

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.

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28
Q

sea breeze

A

wind coming from the water, due to the land heating during the day

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29
Q

land breeze

A

wind coming from the land, due to the land cooling, and the water acting as a heat sink, retaining heat better

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30
Q

chinook

A

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.

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31
Q

mountain waves

A

lentuclar clouds

sever turbulence and wind shear

downdrafts

altimeter to read incorrectly

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32
Q

radiation fog

A

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.

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33
Q

advection fog

A

occurs when air flows from a location where the surface is relatively warm to now which is relatively cool.

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34
Q

frontal fog

A

associated with a front, warm or cold.

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35
Q

arctic sea smoke

A

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.

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36
Q

upslope fog

A

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.

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37
Q

air masses

A

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

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38
Q

fronts

A

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

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39
Q

nautical miles to feet

A

1 nautical mile = 6,000 ft

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40
Q

how to estimate the position of a frontal surface

A

take altitude, convert to miles
take frontal slope ratio
multiply by converted altitude.

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41
Q

occlusion

A

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.

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42
Q

thunderstorms

A

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

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43
Q

passing through a cold front

A

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.

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44
Q

back

A

the direction from which the wind blows decreases, for example, the wind changes from an easterly to a north easterly direction.

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45
Q

convection

A

distribution of heat due to daytime heating of the surface of the earth

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46
Q

compression

A

heating by compression

stable air descends into areas of higher pressure at lower altitudes

47
Q

frontal lift

A

warm less dense air rises over a cold front

48
Q

orographic lift

A

air is forced aloft over mountains by strong winds

49
Q

convergence

A

lifting caused by air drawn into the centre of a low

50
Q

adiabatic cooling by expansion

A

as air expands it will cool

air rising into lower pressure will expand and cool, and often condense into a cloud

51
Q

adiabatic heating by compression

A

as air sinks it will enter an area of higher pressure and the air is compressed and heated

52
Q

stability

A

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
Q

divergence

A

high pressure pushes air down, and it diverted in every direction once it hits the ground.

54
Q

under reading

A

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
Q

over reading

A

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
Q

pressure altitude

A

the altitude read when set to 29.92 hg

57
Q

density altiude

A

pressure altitude adjusted for non-standard temperature.

used to calculate aircraft performance.

58
Q

true altitude

A

the indicated altitude corrected for non-standard temperature between the surface and the altitude at which you are flying

59
Q

dominent airmass in canada

A

winter cA or continental arctic

summer mA maritime arctic

60
Q

arctic airmass

A

most north

61
Q

polar airmass

A

just below arctic, vancouver

62
Q

surface analysis charts

A 
issued 4 times a day 
0000z
0600z
1200z
1800z
63
Q

FG

A

fog

64
Q

PR

A

partial

65
Q

MI

A

shallow

66
Q

BC

A

patches

67
Q

DR

A

drifting

68
Q

BL

A

blowing

69
Q

SN

A

snow

70
Q

DU

A

dust

71
Q

SA

A

sand

72
Q

SH

A

shower

73
Q

RA

A

rain

74
Q

PL

A

ice pellets

75
Q

GR

A

hail

76
Q

GS

A

snow pellets

77
Q

FR

A

freezing

78
Q

DZ

A

drizzle

79
Q

BR

A

mist

80
Q

FU

A

smoke

81
Q

HZ

A

haze

82
Q

VA

A

volcanic ash

83
Q

TS

A

thunder storm

84
Q

SS

A

sand storm

85
Q

DS

A

dust storm

86
Q

VC

A

in the vicinity

87
Q

SQ

A

squalls

88
Q

+FC

A

tornado or waterspout

89
Q

NS

A

nimbostratus

90
Q

ST

A

stratus

91
Q

SC

A

stratocumulus

92
Q

SF

A

stratus fractus

93
Q

CU

A

cumulus

94
Q

CUFRA

A

cumulus fractus

95
Q

AS

A

altostratus

96
Q

AC

A

altocumulus

97
Q

ACC

A

altocumulus castellanus

98
Q

CI

A

cirrus

99
Q

CS

A

cirrostratus

100
Q

CC

A

cirrocumulus

101
Q

TCU

A

towering cumulus

102
Q

CB

A

cumulonimbus

103
Q

GFA

A

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
Q

upper level wind chart winds above 100 knots

A

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
Q

icing

A 
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
Q

frost

A

usually forms overnight from an aircraft parked outside overnight. frozen water vapour accumulates on the airframe

107
Q

clear or glazed ice

A

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
Q

rime ice

A

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
Q

clean aircraft concept

A

frost ice or snow myst be removed from critical surfaces of an aircraft prior to flight

110
Q

if your landing with ice

A

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
Q

worst conditions for picking up ice

A

thin wings
high speed
throughout a cloud with large droplets
high liquid water content

high efficiently of ice pick up is bad

112
Q

▲▲▲ solid line with blue triangles

A

cold front

113
Q

◗◗ solid line with red semicircles

A

warm front

commercial (4 decks)

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