Test 2 Flashcards
(245 cards)
1
Q
What is a Hadley Cell?
A
A convection cell in the atmosphere due to differential heating of the surface.
2
Q
At the equator, air is _____ (rising/falling)
A
rising
3
Q
Where is the ITCZ?
A
The low-pressure belt near the equator, at the solar declination
4
Q
What does ITCZ stand for?
A
Inter-tropical convergence zone
5
Q
The tradewinds converge where?
A
At the equator
6
Q
The ITCZ has what kind of weather?
A
light winds with heavy precipitation
7
Q
30* North and South is known as the _____ latitudes
A
horse
8
Q
In the horse latitudes, air is ____
A
descending
9
Q
30* N and S are _____ pressure belts
A
high
10
Q
Which winds diverge at the horse latitudes?
A
Westerlies and trade winds
11
Q
What is the weather like within the horse latitudes?
A
light winds with low precipitation. Dry.
12
Q
60* North and South are known as the ______
A
Polar front
13
Q
The polar fronts are ____ pressure belts
A
low
14
Q
Air ______ at the polar fronts
A
rises
15
Q
What winds converge at the polar fronts?
A
Easterlies and westerlies
16
Q
What is the weather like at the polar fronts?
A
light winds, moderate precipitation
17
Q
Why don’t the polar fronts have as much precipitation as the ITCZ?
A
It is much colder, and cold air can’t hold as much moisture
18
Q
At 90* N and S, air is _____
A
sinking
19
Q
90* N and S are known as the Polar _____
A
high
20
Q
The polar high is a ____ pressure area
A
high
21
Q
What winds diverge at the polar highs?
A
easterlies
22
Q
What is the weather like at the polar highs?
A
dry conditions
23
Q
What are the jet streams?
A
High velocity currents of air in the upper troposphere
24
Q
How high are the jet streams in the air?
A
9-15 km in altitude
25
How fast are the winds in the jet streams?
More than 100 kt
26
What direction do the jet streams flow?
West to east
27
How many jet streams are there?
4
28
What are the two sets of jet streams called?
Polar jets and subtropical jets
29
Where are the polar jets located?
60* N and S
30
Where are the subtropical jets located?
30* N and S
31
The ITCZ moves with what?
the seasons
32
The change of the ITCZ's location is more distinguished over _____ than _____ because water doesn't change temperatures as quickly.
Land than water
33
The ITCZ is responsible for _____ in the tropics and subtropics
monsoons
34
The ITCZ creates semi-permanent _________
high and low pressure sectors
35
In a low pressure center, the air is _____
rising
36
Low pressure centers are termed _____
cyclones
37
A cyclone is characterized by what?
converging, rotating winds
38
In the northern hemisphere, cyclones spin ____
counterclockwise
39
In a high pressure center, the air is _____
sinking
40
High pressure centers are termed ____
anti-cyclones
41
anti-cyclones are characterized by what?
Diverging, rotating winds
42
Air masses are what?
large, 3-dimensional bodies of air in the atmosphere
43
Air masses have consistent ____ at all levels?
temperature and humidity conditions
44
Air masses develop where?
over "source areas"
45
What are source areas?
Broad areas of the earth's surface that have rather homogeneous conditions
46
As an air mass moves over a source area, what happens?
they take on the characteristics of the area
47
What are the 8 air mass classifications?
Maritime arctic, maritime polar, maritime tropical, maritime equatorial, continental arctic, continental polar, continental tropical, continental equatorial.
48
What is a front?
A boundary between two air masses with different characteristics and densities.
49
A front is named for what?
The advancing air mass
50
The less dense air mass in a front is _____
pushed upwards
51
A front creates a ______ at the surface.
low pressure area
52
As a cold front approaches, temperatures are _____
stable and warm
53
As a cold front approaches, cumulus clouds develop into _____
cumulonimbus clouds
54
As a cold front approaches, what is the precipitation like?
Heavy precipitation, short duration
55
As a cold front approaches, what kind of weather is there?
lightning, t-storms, tornado, hail
56
As a cold front approaches, pressure ____
drops
57
As a cold front passes, temperatures ____
drop
58
As a cold front passes, what happens to the clouds?
they clear out
59
As a cold front passes, winds do what?
shift directions
60
As a cold front passes, pressure _____
rises
61
When a warm air mass moves into the area of a colder air mass, what happens to the warm air?
It is pushed aloft
62
A warm front that moves into the area of a colder air mass creates what kind of slope?
gentle slope
63
As a warm front approaches, temperatures are _____
stable and cold
64
As a warm front approaches, air pressure _____
drops
65
As a warm front approaches, _____ clouds form how far in front of the air mass?
cirrus, 500 miles in front
66
Why do the clouds form so far in front of a warm front?
because of the gentle slope
67
Cirrus clouds get ____ as a warm front approaches.
thicker
68
What is the progression of cirrus clouds when a warm front approaches?
cirrus, cirrostratus, altostratus, stratus, nimbostratus, and sometimes fog.
69
Clouds are _____ as warm front approaches
lowering
70
As a warm front approaches, what is the precipitation like?
Moderate to ight precipitation, long duration
71
As the warm front passes, temperatures...
warm rapidly
72
As a warm front passes, clouds and precipitation ____
clear
73
As a warm front passes, winds _____
shift direction
74
As a warm front passes, air pressure _____
rises
75
During a stationary front, a warm air mass is
sitting next to a cold air mass with neither advancing
76
Weather with a stationary front is _____
highly variable
77
In a stationary front, there can be clouds and precipitation if there is _____
any convergence of winds
78
What is an occluded front?
When cold air moves faster than warm air mass and catches up to it.
79
In an occluded front, what happens to a warm air mass?
it gets pushed completely aloft and out of the way
80
What is the weather like in an occluded front?
mixture of cold front and warm front weather
81
What are the clouds like in an occluded front?
cumulus and cumulonimbus mixed with stratus and nimbostratus.
82
What is the precipitation like in an occluded front?
heavy precipitation and slowly lightens
83
What is a dry line also known as?
Dew point front
84
What causes a dry line?
When a dry air mass moves into the area of a humid air mass of the same temperature
85
What happens in a dry line?
The dry air mass is pushed upwards
86
A dryline is pushed _____ during the day
eastward
87
A dryline is pushed _____ during the night.
westward
88
What kind of atmosphere does a dryline create?
extremely unstable
89
What kind of clouds does a dryline create?
Very large cumulonimbus
90
What else does a dryline create?
Supercells, very strong thunderstorms and tornadoes.
91
Behind a dryline, what are common?
dust storms.
92
Where do midlatitude cyclones form?
between 30 and 70 degrees latitude
93
In what zone do midlatitude cyclones form?
In westerlies zone
94
What speed do midlatitude cyclones travel?
20-40 mph
95
What is the wind speed of a midlatitude cyclone?
30-40 kt
96
When are midlatitude cyclones most intense?
in winter
97
What are responsible for the day-to-day weather we experience?
midlatitude cyclones
98
What does a midlatitude cyclone start as?
A stationary front
99
What triggers the bend in a stationary front?
Rossby waves in the jet stream
100
As the jet stream comes out of a rossby wave, what happens?
it diverges and pulls air up from below, creating a low pressure center, cold front, and warm front
101
Once a cold front and warm front are created, what happens?
The cold air mass catches up to the warm air mass and creates an occluded front
102
What happens to an occluded front as it grows in size?
it continues growing until the entire warm air mass is pushed aloft, shutting down clouds and precipitation
103
What is the weather associated with a warm front approaching in a mid-latitude cyclone?
Temp steady, pressure drops, nimbostratus clouds, steady continuous rain, south-southeast winds
104
What is the weather associated with a warm front passing?
Temp rising, pressure increasing then steady, cumulus clouds, no precip, south-southwest winds
105
What is the weather associated with a cold front approaching?
Temp rising and steady, pressure drops, cumulonimbus clouds, thunderstorms, south-southwest winds
106
What is the weather associated with a cold front passing?
temp drops, pressure rises, clouds clear, no precip, north-northwest winds
107
What alternates with cyclones?
mid-latitude anticyclones
108
What kind of weather does an anticyclone have?
None! No fronts
109
Anticyclones do what to the air?
pushes it away
110
As the jet stream ______ a rossby wave, it _____ and creates a high pressure center
enters, converges and pushes air down
111
As air sinks in the high pressure center, what happens?
it compresses in volume and warms adiabatically
112
Within the anti-cyclone, relative humidity _____, causing what?
decreases, causing clear and dry conditions
113
The problem with anticyclones, is that they _____
block cyclones from moving in.
114
What is a tropical cyclone?
A low pressure center characterized by converging rotating winds that form between 5* and 20* latitude
115
What direction do tropical cyclones move in?
east-west direction
116
tropical cyclones are ______ of a mid-latitude cyclone
half the size
117
How many air masses do tropical cyclones span?
one
118
What kind of fronts do tropical cyclones have?
None
119
A tropical cyclone moves at what speed?
20-40 mph
120
What is the first component of hurricane formation?
Large area of warm sea surface temperatures over 80*F
121
Warm water acts as a ____ for hurricanes?
fuel source
122
What is the second component of hurricane formation?
Convergence of surface winds
123
What does the convergence of surface winds do?
Concentrates clouds and precipitation in one area, starts rotation, organizes the storm, creates tropical waves
124
What is the line of low pressure known as?
trough
125
What is the third component of hurricane formation?
Conditions in the atmosphere which promote strong convection.
126
What does strong convection allow?
allows the cyclone to grow in size
127
Two things that can promote strong convection are what?
a) Strong temperature gradient and b) weak upper-level winds in the atmosphere.
128
Usually, weak upper winds in the atmosphere occur during what?
la nina
129
What is the first stage of tropical cyclone development?
Tropical disturbance
130
What is a tropical disturbance?
A mass of storms with a slight rotation.
131
During a tropical disturbance, winds rotate at what speed?
20-34 kt
132
What is the second stage of hurricane development?
Tropical depression
133
What is a tropical depression?
An increase in wind speeds to 20-34 kt and better organized.
134
What is the third stage of a tropical cyclone?
Tropical storm
135
What are the characteristics of a tropical storm?
Increase in size, wind speeds between 34-64 kt, no eye, increased organization, given a name
136
Why are the tropical storms named?
for tracking purposes
137
What is stage 4 of hurricane formation?
Hurricane
138
What are the characteristics of a hurricane?
wind speeds exceed 64kt, large well organized storm, eye
139
Why was 2013 a low hurricane year?
Unfavorable atmospheric conditions over the gulf of mexico
140
What are the parts of a hurricane?
Center, eye wall, spiral rain bands
141
What is the center of a hurricane?
The eye
142
What are the characteristics of the eye of a hurricane?
low pressure center, very calm, light winds
143
What are the spiral rain bands?
bands of clouds and precipitation moving out from the eye wall with increased intensity towards the eye.
144
What is the eye wall?
Ring of intense storms that rotate around the eye with the most rain and fastest winds
145
What are the hazards of a tropical cyclone?
1) Strong winds covering large areas
2) Hurricane-spawned tornadoes
3) Heavy rainfall
4) Storm surge
146
What part of the hurricane has the strongest winds, and why?
The northeast corner, because the wind speed and the speed of the hurricane moving north are added together
147
The average hurricane produces how many gallons of rainfall each day?
1 trillion gallons
148
Hurricanes cause extensive floods far inland when what?
They get stuck on a topographic barrier
149
What causes a storm surge?
Winds pushing a bulge of water that is lifted up by the low pressure center
150
What causes the most fatalities?
storm surge
151
What 3 things cause the height of a storm surge?
Wind speeds, fetch, and shape of the coast
152
What is fetch?
Distance of open water the storm travels over
153
Fetch: The longer the duration of the storm at a specific size, the ______
higher the surge it is going to be
154
A _____ shaped sea floor can increase the size of the surge
gently sloped
155
Bays and inlets do what?
Funnel the storm surge and increase height
156
What is the scale used to measure the magnitude of a hurricane event?
The Saffir-Simpson scale
157
What is the Saffir-Simpson scale based on?
the maximum sustained wind speed at the time of observation
158
What is the wind speed of a category 1 hurricane?
64-82KT
159
What is the wind speed of a category 2 hurricane?
83-95 kt
160
What is the wind speed of a category 3 hurricane?
96-112 kt
161
What is the wind speed of a category 4 hurricane?
113-136 kt
162
What is the wind speed of a category 5 hurricane?
> 136 kt
163
What are thunderstorms?
small, convective storms that produce thunder and lightning
164
What are thunderstorm cells composed of?
1 updraft, 1 downdraft, a single cumulonimbus cloud
165
What is an updraft?
warm, moist air rising
166
What is a downdraft?
cold, drier air falling
167
What is lightning?
The discharge of electricity from a cloud
168
What is the first step of lightning?
Two types of ice are present
169
What are the two types of ice that must be present for lightning to form?
crystals and hailstones
170
What occurs within the cloud between the two types of ice?
They rub against each other and create a static charge, making the hail negatively charged and the crystals positive
171
What is the second step of the formation of lightning?
Hail sinks to the bottom and crystals rise to the top, making the cloud like a battery.
172
What is the third step of lightning formation?
Ground becomes positively charged
173
What is the fourth step of lightning formation?
Charges in the cloud become unbalanced
174
What does the cloud send down to look for positive charges?
A "stepped leader"
175
What is a stepped leader?
A small tendril of electrons with a negative charge
176
What is stepped 5 of the formation of lightning?
Ground sends up a streamer
177
What is a streamer?
a positively charged tendril
178
What is step 6 of the formation of lightning?
stepped leader and streamer connect, electricity discharged as a "return stroke"
179
What is thunder?
The sound produced by lightning
180
What causes thunder?
Lightning very quickly heats the atmosphere to very high temperatures, causing the rapid expansion of air.
181
What is step 1 of the thunderstorm life cycle?
Cumulus stage
182
What occurs during the cumulus stage?
A cumulus cloud grows vertically with an updraft. Expands in volume and warms adiabatically. RH increases. Condensation level lifts above 0*F isotherm, bergeron process
183
What is step 2 of the thunderstorm life cycle?
The mature stage
184
What happens during the mature stage?
Falling precipitation creates a cool downdraft. Top of the cloud spreads into a anvil. Most intense part of the storm
185
What direction is the anvil pointing on a cumulonimbus cloud?
The direction the storm is moving
186
What is step 3 of the thunderstorm life cycle?
Dissipating stage
187
What occurs during the dissipating stage?
The downdraft strengthens and updraft weakens. Downdraft spreads out and cuts off the updraft, making precipitation end. Cloud evaporates from the bottom-up
188
What are the types of thunderstorms?
single-cell thunderstorm, multicell thunderstorm, squall, supercell thunderstorm
189
What must a severe thunderstorm do?
At least one of the following: create hail >= 1 in, winds > 50 kt, or create tornado
190
What is a single cell thunderstorm composed of?
1 cumulonimbus cloud with one updraft and one downdraft
191
How long does a single cell storm last?
20-30 min
192
What kind of weather does a single cell storm produce?
small hail, heavy rains, thunder and lightning
193
What is a multicell thunderstorm composed of?
Multiple cumulonimbus clouds that move together as a single unit with multiple updrafts and downdrafts
194
In a multicell, the downdraft of one cell does what?
creates a new updraft in another
195
What kind of weather comes from a multicell?
larger hail, stronger winds, weak tornadoes
196
What is a squall?
A line of thunderstorm cells along a cold front
197
What kind of weather might we see in a squall?
large hail, heavy rain, weak tornadoes, strong winds
198
What might you see in a squall's clouds?
a shelf cloud
199
What is a shelf cloud?
A cloud that slopes down and away from leading edge of the squall
200
What does a shelf cloud mean?
shit is about to get real. strongest part of the storm
201
What is a supercell?
a massive group of thunderstorm cells rotating and moving as one
202
What does a supercell interact with to begin rotating?
upper-level winds
203
What weather might you see in a supercell?
very large hail, huge tornadoes, winds >90 kt
204
What is a tornado?
A rapidly rotating column of air around an intense low pressure center
205
In the northern hemisphere, most tornadoes spin which direction?
counter-clockwise
206
What direction do most tornadoes move?
southwest to northeast
207
What is the average length of a tornado's path?
7 km
208
When are tornadoes most common?
spring and early summer
209
What is the first step of tornado formation?
convergence or crossing of warm low level winds with cooler upper level winds
210
What is step 2 of tornado formation?
air between upper and lower winds create wind shear (spinning)
211
What is step 3 of tornado formation?
Updraft of thunderstorm lifts spinning tube into a vertical position. Called mesocyclone
212
What is step 4 of tornado formation?
Precipitation wraps around mesocyclone
213
What is step 5 of tornado formation?
Downdraft wraps around mesocyclone, pulling and stretching it. rotation speed increases. when it touches ground, it's a tornado.
214
What is climate?
long-term statistics of atmospheric conditions that are calculated over decades, centuries, and millenniums
215
What is more predictable, weather or climate?
climate
216
Why do we classify climates?
to simplify and organize data about a complex system and to compare climates.
217
What is the koppen climate classification based on?
annual and monthly temperature and precipitation data
218
What seasons does the koppen climate classification consider?
summer and winter
219
What is the A group?
tropical humid
220
What is the C group?
mild mid-latitude
221
What is the D group?
severe mid-latitude
222
What is the E group?
polar climates
223
What is the B group?
dry climates
224
What is the H group?
highland climates
225
What does the second letter in the koppen classification mean?
seasonal precipitation patterns
226
What does the third letter in the koppen classification mean?
seasonal temperature patterns
227
What is a climate system?
A series of interconnected spheres exchanging matter and energy
228
What are the 5 spheres of the climate system?
1) atmosphere 2) cryosphere 3) hydrosphere 4) geosphere 5) biosphere
229
What is climate change?
change in the statistics of a climate that lasts at least 10 years
230
What is climate change initiated by?
A forcing mechanism
231
What is a forcing mechanism?
A process that initiates a climate change in the system.
232
What is a feedback mechanism?
Processes in the climate system that alter a climate change already underway
233
What is positive feedback?
Processes that enhance a change already underway
234
What is negative feedback?
processes that suppress a change already underway, decreasing impact
235
What are long-term climate forcers?
things that do not operate on human timescales. Take billions of years
236
What are some forcing mechanisms?
1) solar cycle 2) ocean oscillations, 3) Volcanic activity 4) anthropogenic climate forcing
237
The solar cycle operates on an _____ cycle
11 year
238
What are the symptoms of a solar cycle?
sunspots and faculae
239
A high number of solar symptoms means what?
more solar activity
240
What are ocean oscillations?
fluctuations in sea surface temperature and pressure centers over oceans
241
What do volcanoes release?
dust/ash and SO2.
242
Aerosols do what to sunlight?
reflect sunlight and have a cooling impact on climate
243
What is anthropogenic climate forcing?
the unintended side effects of humans on the climate
244
What are the two was humans effect the climate?
a) land degradation b) changing chemical composition of the atmosphere
245
What are the greenhouse gases that humans have increased in the atmosphere?
CO2, Methane, Nitrous Oxide, Ozone, Manmade gases
