Midterm2 Flashcards
1
Q
lower altitude =
A
higher pressure
2
Q
water can be sucked up a tube but only at
A
35 feet
3
Q
variations in surface air pressure
A
elevation/altitude and vertical motion (convection)
4
Q
vertical motion (convection)
A
rising air causes low pressure; subsiding air causes high pressure
5
Q
what changes pressure on the surface of the earth
A
vertical motion
6
Q
only thing that is affecting subsiding air
A
vertical motion
7
Q
what causes vertical motion of air?
A
thermal causes; dynamic causes
8
Q
thermal causes
A
warm air goes up, cold air go down
9
Q
dynamic causes
A
diverging air high above the surface (aloft) causes air to be lifted or to rise; converging air aloft causes air to subside
10
Q
rising low, low pressure
A
cyclones
11
Q
subsiding high, high pressure
A
anticyclones
12
Q
pressure gradient direction
A
always perpindicular to isobars, away from high toward low
13
Q
pressure gradient are always on a
A
horizontal plane, and greater where isobars are closer together
14
Q
pressure gradient causes
A
wind, steeper pressure gradient means higher wind speed
15
Q
coriolis effect determines
A
wind pressure; equal to coriolis force
16
Q
4 rules for coriolis
A
- direction of coriolis deflection is determined by hemisphere; 2. magnitude of coriolis deflection is determined by latitude; 3. coriolis effect also increases with wind speed; 4. coriolis always acts at right angles to wind direction
17
Q
wind direction combination of
A
direction of pressure gradient; amount of direction of deflection due to coriolis; coriolis deflection is in turn controlled by wind speed and latitude
18
Q
geo balance depends on
A
no curvature of isobars; no friction
19
Q
wind from the north is
A
north wind or northerly
20
Q
wind from the south is
A
south wind or southerly
21
Q
if a shoreline or a slope faces into the wind
A
windward
22
Q
if a side is facing away from the wind
A
leeward
23
Q
winds that dominate from a particular direction
A
prevailing winds
24
Q
circulation around northern hemisphere low pressure
A
counterclockwise and converging toward the center
25
rules for determining wind direction
point down the pressure gradient, turn to the right (geotropic wind), back off about 30 degrees (surface wind)
26
circulation around northern hemisphere high pressure
clockwise and diverging away from the center
27
centers of low pressure
zones of rising air, associated with clouds and precipitation, cyclonic, centers of convergence of the surface, associated with divergence aloft
28
centers of high pressure
zones of subsiding air, associated with clear skies and calmer weather, anticyclonic, centers of divergence, convergence aloft
29
ridges
pressure goes down on both ides of the ridge, marks a line of relatively high pressure in between two lows, a zone of divergence and subsidence
30
troughs
pressure goes up on both sides of the trough, marks a line of low pressure in between two highs, a line of convergence and rising air
31
subtropical highs most strongest in summer
anticyclonic
32
subtropical jet
located above STH, zone of convergence aloft
33
polar front jet
located above polar front, produced by steep pressure gradient aloft
34
pressure gradient aloft is controlled by
air temperatures: warmth in tropics; cold in polar regions
35
lines are close together
where the jet streams are
36
gas to solid
decomposition 670 cal
37
takes energy to go
from higher energy to lower
38
energy from the sun
causes/powers the hydrological cycle
39
freezing water to ice
gives off heat
40
for water to freeze
heat has to be extracted
41
what controls humidity
its course is evaporation form the earths surface; it is limited in amount by air temperature (primarily); temperature controls capacity for water vapor
42
air parcel
has known volume, pressure, temperature and density
43
humidity
amount of water vapor in an air parcel at a particular time and place
44
air parcels can only contain
a certain amount of water vapor - their capacity for vapor is determined by temperature
45
warm air has
fast moving molecules, low density and high volume
46
cold air has a
high density and low volume low capacity for vapor
47
saturation is reached when
air has its maximum capacity of vapor
48
saturation capacity increases
as temperature increases
49
how we measure humidty
actual measures, relative humidity, proxy measures
50
actual measures
vapor pressure (mb), mixing ratio - w (g/kg), specific humidity - q (g/kg), vapor density pv (g/m3)
51
vapor pressure
in a mixture of gases the total p = sum of the partial pressure of the constituent gases
52
humidity cannot be at any value
above the saturation curve
53
relative humidity
actual humidity content/ capacity of current air T
54
proxy measures
dew point temperatures, wet bulb temperature
55
temp of air at saturation
dew point = td ( temp to which air must be cooled to induce concentration)
56
to bring air to its dew point temp
it must be cooled
57
two ways to cool the air
remove heat from the air, increase its volume (exchange sensible heat for work)
58
adiabotic
no change in energy content
59
remove heat
diabetic process; a change in heat content of air parcel
60
increase its volume
adiabatic process; no change in heat content of air parcel; energy just changes form from thermal to work
61
RH increases
temp decreases
62
Rh decreases
temp increases
63
adiabatic cooling
rising air parcels cool clouds form
64
adiabatic warming
sinking air air parcels warm clouds dissipate
65
2 types of lapse rates
environmental and adiabatic
66
environmental lapse rates
rate of temp change with altitude in troposphere
67
adiabatic lapse rate
rate of temp change for a vertically change; moving air parcel due to its change in volume; not measured but calculated by thermodynamics
68
dry adiabatic lapse rate
10 C/1000 m or 5.6 F/1000 feet
69
wet adiabatic lapse rate
5C/1000 meters
70
stability
is the degree to which an air parcel resists vertical motion
71
buoyant air parcels are
unstable - like a hot air balloon
72
buoyancy results from
the air parcel being less dense than surrounding air, and it rises
73
buoyancy
is caused mainly by temp difference between the air parcel and the surrounding air; air parcel warmer than surrounding air, less dense and rise
74
stable ari
skies are generally clear or clouds that do form are flattened
75
unstable air
clouds tend to build upward, often precipitation will be result (lighting)
76
accessing stablity
need to know environmental lapse rate
77
types of fog
adiabatic types, adiabatic types; evaporation
78
adiabatic types of fog
radiation fog and advection fog
79
adiabatic types of fog
upslope fog
80
evaporation types of fog
steam fog and frontal fog
81
radiation fog
form when the ground loses heat by infrared radiation to space on clear nights; fog forms in low-lying areas where cold air settles and pools; fog forms on calm clear nights in most cases
82
advection fog
horizontal movement of air; warm moist air travels across a cold surface; cold surface extracts heat from air cooling to its dew point; heat is being lost; forms over a wide area; common over cold water on west coasts in summer
83
upslope fog
air moves up a slope, cools adiabotically reaching its dew point temp; evaporation (steam fog); warm moist surfaces evaporates water vapor into cold air; air is cold water is warm = steam fog
84
frontal fog
rain falling through cold air at surface; precipitin along frontal boundary
85
cloud form families
cirriform, stratiform, cummliform, alto clouds, nimbo nimbus
86
cirrostratus
represents rain coming
87
ways air is lifted
orographic lifting, frontal, convection
88
lifting mechanisms
orographic, frontal, convection, convergence
89
types of convergence
air stream convergence, cyclonic convergence, speed convergence which is a indirect affect on topography
90
how precipitation forms
cloud droplets form on a condensation nucleus - dust soot salt pollen; so small that the slightest air movements keep them aloft; cloud droplets and tiny ice crystals must grow thousands of times their original volume in order for clouds to produce precipitation
91
two major theories of precipitation formation
collision coalescence process and ice crystal (bergeron) process
92
collision coalescence process
warm clouds which contain only liquid water; droplets can fall faster than surrounding objects; collision with smaller droplets increases the size of the larger ones; air drags pulls apart the largest drops; they turn collide and grow by coalescence as they fall
93
ice crystals (Bergeron) process
cold clouds having a mix of water droplets and ice crystals; found both in higher altitudes and in higher latitudes; water droplets are supercooled and the temps are below freezing; water droplets small, ice crystals big; vapor pressure is lower around ice; vapor pressures higher around liquid water
94
distribution of precipitation over time
seasonal movement of wind and pressure zones can cause large differences in precipitation during the year
95
orographic lifting mechanism
cause it to rain a lot in Alaska and Oregon
96
air mass
large body of air that has relatively homogeneous temperature and moisture characteristics throughout
97
air masses get those characteristics from
their source regions; if source region is a land mass, air mass will be dry; if it is from an ocean, air mass will be both warm and moist
98
when one air mass moves up against another air mass
it forms a front at the boundary between two air masses
99
north american air masses cold/cool
continental arctic = CA; continental polar = cP; maritime polar = mP; polar high pressure; over continuous at high latitudes; more dominant in winter
100
north american air masses warm/hot
continental tropical = cT; maritime tropical = mT; subtropical high pressure; tropical and subtropical oceans (maritime); desert (continental); more dominant in summer
101
air mass modification
continental polar (cP) is changed to mP as it travels across an ocean, picking up heat and humidity
102
air masses are modified when
they travel out of their source region
103
when an air mass moves, its leading edge is a
front
104
front
place where one air mass comes up against another type of air mass
105
type of front is determined by
what type of air mass is advancing: cold or warm
