Final Flashcards
(158 cards)
1
Q
What direction are trade winds and polar winds?
A
Easterlies
2
Q
What direction are winds in the upper atmosphere?
A
Westerlies
3
Q
What direction is southerly flow in the northern hemisphere?
A
Westerly
4
Q
What direction is northerly flow in the northern hemisphere?
A
Easterly
5
Q
Where do dry regions occur?
A
Where wind diverges (30°N and S)
6
Q
Where do wet regions occur?
A
Where wind converges (ITCZ and polar front)
7
Q
What are the key features of January in wind flow patterns?
A
Icelandic and Aleutian Low and Siberian High
8
Q
What are the key features of July in wind flow patterns?
A
Bermuda and North Pacific High and Monsoonal Low
9
Q
What are the features of the subtropical highs?
A
East limb: descending branch of Hadley Cell, West limb: bringing warm/moist air from equator, South limb: trade winds
10
Q
Why are there not deserts everywhere at 30°?
A
Because deserts only occur on the east limb of subtropical highs
11
Q
What happens when air rises?
A
Precipitation tends to be abundant
12
Q
Where is the low in the sea breeze?
A
Over the land
13
Q
What time of day does seabreeze occur?
A
During the day
14
Q
Where is the low in land breeze?
A
Over the water
15
Q
What time of day does land breeze occur?
A
At night
16
Q
Is there a greater change in pressure at the surface in sea breeze or land breeze?
A
Seabreeze
17
Q
Is there a stronger pressure gradient, force, and higher winds with sea breeze or land breeze?
A
Sea breeze
18
Q
What is a thermal low?
A
When there is low surface pressure occurring where there is the most warming and high surface pressure where there is more cool temperatures
19
Q
What is the Asian monsoon?
A
The change in annual Winflo patterns associated with the winter and summer
20
Q
Where are monsoons located?
A
Throughout southeast Asia, Africa, and the US
21
Q
What direction does valley breeze blow?
A
Uphill
22
Q
What direction do mountain breezes blow?
A
Downhill at night
23
Q
When do strong katabatic winds form?
A
When cold winds rush downhill from an elevated plateau, covered with snow, with the warm temperatures at the bottom relative to the top, creating a pressure differential that results in downward flow
24
Q
What is a chinook wind?
A
A warm wind blowing down a mountain often occurring on the east slope of the Rockies. It is fundamentally different from other local wins because it’s not a thermal low, but it is driven by the westerly flow across the Rockies.
25
What is the rising air on the west of a chinook mountain like?
Cooling at the moist adiabatic lapse rate
26
How does the ITCZ shift throughout the year?
It moves far south word in January and north word in July and is the expression of the monsoon over Southeast Asia
27
What is surface circulation?
Ocean currents are masses of water that flows from one place to another and surface currents develop from friction between the ocean, and the wind that blows across the surface, they are huge slowly, moving gyres
28
What direction are gyres in the northern hemisphere?
Clockwise, mimicking the overlying subtropical high pressure systems
29
Where are the five main gyres?
North pacific, south pacific, north, Atlantic, south Atlantic, Indian Ocean
30
What are gyres deflected by?
The Coriolis effect
31
What is the importance of surface circulation to climate?
Currents from low latitudes into higher latitudes transfer heat from warm to cooler areas, and the influence of cold currents are most pronounced in the tropics, or during the summer months in the middle latitudes
32
What is upwelling?
The rising of cold water from different layers, most characteristic along the west coast continent, bringing greater concentration of dissolved nutrients to the ocean surface
33
What directions do winds blow along the coast to get upwelling?
Parallel to the coast to transfer water out to sea
34
What is the Ekman spiral?
A diagram that shows the direction of each ocean column and proves that the net movement of water is perpendicular to the wind direction
35
Where is upwelling common?
Along eastern boundary currents, which are along the west coast of continents
36
What is the second major area of upwelling?
Along the equator, where the waters diverge
37
Why are high latitude oceans nutrient rich?
Cool sea surface temperatures result in a less stable ocean layer, which allows for more mixing
38
What is deep ocean circulation?
Response to density differences also called thermohaline circulation
39
What factors create a dense mass of water?
Colder water is denser and greater density with increased salinity
40
What are the different parts of thermohaline circulation?
Dense water from the north Atlantic deep water flows to warmer, less dense water. Antarctic bottom water is even colder and denser, continuing to drive ocean currents. Warmer surface flow completes the loop
41
Why is north Atlantic Deepwater created?
Evaporation from warm golf stream further south leaves ocean saltier as the current travels poleward and sea ice formation results in saltier waters due to brine rejection, so they are left with cold salty water that sinks in the north Atlantic
42
Why my production of NADW shut off?
Freshening up the north Atlantic due to sea ice melt, ice sheet melt, more precipitation then evaporation, or more river flow into the Arctic in Russia
43
What could happen if the NADW shuts down?
The global conveyor belt could be limited, causing less warming in northwest Europe
44
What is the Walker Circulation?
An east-west Hadley Cell like circulation in the Pacific, resulting in offshore flow off South America, and upwelling
45
What does el niño do?
Atmospheric pressure decreases over the eastern Pacific and rises over the western Pacific, this causes the trades to weaken or reverse directions, enhancing the countercurrent that brings warm water from the west over a vast region of the tropical pacific.
46
What does la niña do?
La niña enhances the trade winds in the walker circulation, which leaves rising air and heavy rain over the western pacific and sinking air and dry weather in the east. When the trades are strong, the water around the eastern pacific becomes cool
47
Is there upwelling in El Niño or la niña?
la niña
48
Is ENSO shorter term or longer term?
Shorter term
49
What does the Southern Oscillation Index measure?
The difference in pressure between Darwin, Australia (western Pacific) and Tahiti (Central Pacific), with a larger pressure difference indicating a stronger high off south America and a strong low off of Indonesia, or La Niña conditions
50
What are conditions in the US due to El Niño?
Fewer Atlantic hurricanes, wetter California and Gulf Coast
51
What are conditions in the US due to La Niña?
More Atlantic hurricanes and more tornadoes in Tornado alley
52
What is the Pacific Decadal Oscillation?
The typical sea surface temperature departure from normal
53
What are the conditions of the warm phase of the PDO?
A stronger Aleutian low, with more storms in Alaska and fewer in the PNW, so more salmon in Alaska
54
How long is the cycle of PDO?
20-30 years
55
What is the North Atlantic Oscillation?
Change in surface atmosphere pressure and typical weather patterns associated with a warm, positive phase, and a cool, negative phase
56
What is the positive phase of the NAO like?
Strengthened westerlies, with warm/wet winters in N Europe, mild/dry winters in central/south Europe, and wet/mild winters in eastern US
57
What is the negative phase of the NAO like?
mild/wet winters in Spain/mediterranean, cold/dry winters in N Europe, and cold/snowy in eastern US
58
What is the length of NAO?
Short, like ENSO
59
What is Arctic Oscillation?
Change in surface atmospheric pressure in polar regions and typical winter weather patterns associated with a warm phase and a cold phase. Very similar to NAO, just another way to measure the same thing
60
What is the Atlantic Multidecadal Oscillation?
Similar to PDO in timeline, but measures changes of sea surface temperature in the North Atlantic
61
What does the AMO affect?
Temperature and rainfall in the Northern Hemisphere, especially droughts in the midwest and possibly Atlantic hurricanes
62
What is the first stage in the growth of a thunderstorm?
The cumulus stage
63
What does the cumulus stage of a thunderstorm include?
Vertical growth; release of latent heat; evaporates at top due to dry air, but moistens with time; updrafts only
64
What is the second stage of thunderstorm development?
The mature stage
65
What does a mature stage of a thunderstorm look like?
Downdrafts develop; following precipitation evaporates due to entrainment, drier air resulting in cooling which drives descent
66
What is the gust front?
Cold downdraft spreading out at ground, may enhance updraft by forcing warm, humid air up
67
What is the last stage of a thunderstorm?
The dissipating stage
68
What does the dissipating stage of a thunderstorm include?
Updraft weakens as gust front moves on; downdraft dominant
69
What is a squall line?
A line of thunderstorms along cold front or in front of it
70
What is a mesoscale convective complex?
Thunderstorms organized in large circular weather system
71
What is a microburst?
An extreme down burst resulting from downdraft hitting the ground
72
What is lightning?
A discharge of electricity – extreme heating of atmosphere results in a shockwave and thunder
73
What is the time between lightning and thunder?
Five seconds per mile
74
What is the development of a lightning strike?
A negative charge near the bottom of the cloud becomes large enough to overcome the air's resistance, a flow of electrons- the stepped leader- rushes towards the earth. As the electrons approach the ground, a region positive charge moves up into the air through any conducting object, including trees, buildings, and even humans. When the downward flow of the electrons meets the upward surge of positive charge, and strong electric current carries positive charge upward into the cloud.
75
What is shear?
Change in wind velocity with height
76
What are severe thunderstorms?
Large hail, strong downdrafts, or tornadoes
77
What is a supercell?
If a strong sheer and changing wind direction with height, storm can move so downdraft does not cut off updraft, creating horizontal spin
78
What are the conditions of a tornado?
Warm humid air at surface overlain by cooler dry air aloft, very unstable
79
What is a tornado?
Rapidly rotating column of air about an intense low with circulation that reaches the ground, most are counterclockwise, some are clockwise
80
What is the diameter of a tornado?
100 to 600 m
81
What is the speed of a tornado?
20 to 40 knots
82
What is a mesocyclone?
A rotating tube by updraft into storm
83
How is a tornado produced?
By rear flank downdraft interacting with inflow at the ground
84
What are clouds like in a tornado?
Forms with updrafts but inflowing air cools and condenses and causes descent to surface
85
How can a gust front enhance updraft?
By forcing it up
86
What moves a tornado system?
Strong wind shear, so downdraft does not cut off updraft
87
What is a hurricane?
An organized mass thunderstorms with a strong circular flow around low pressure composed of convective clouds with air ascending in spiraling motion
88
What speed are winds in a tropical cyclone?
Over 74 mph
89
Where do hurricanes form?
Over the north Atlantic and the north pacific
90
What is the diameter of a hurricane?
Over 500 km, with a 40 km eye
91
What is hurricane season for Atlantic hurricanes?
June through November
92
What direction is the circular flow of the hurricane?
Counter clockwise in the northern hemisphere
93
What is a tropical disturbance?
A wave that moves slowly westward bringing fair weather on the western side and showers on the eastern side, usually with bending streamlines around the 700 mb level
94
What does sea surface temperatures have to be for hurricane?
Over 26.5°C
95
What kind of windshear is needed for hurricane?
No wind shear, a strong wind shear destroys hurricanes
96
What kind of humidity is needed for a hurricane?
High
97
At what latitude do hurricanes occur?
5 through 20°
98
Where can convergence for hurricane occur?
Tropical wave over Africa for Atlantic hurricanes, the ITCZ, or mid latitude front extending to tropics
99
When do hurricanes dissipate?
Over colder water or land
100
What is the difference between a mid latitude storm and a hurricane?
Mid latitude storms are a surface low intensified with height; while a hurricane is a surface low that weakens with height
101
Where are the higher sustained winds be on a hurricane moving north in the Atlantic?
The eastern side
102
What was the Laurentide ice sheet over?
Eastern North America
103
What was the cordilleran ice sheet over?
western north America
104
How do we find evidence for past climates?
lake and marine sediments, pollen grains, speleothems, ice cores, historical record, glacier and ice caps, and tree rings
105
If the ratio of 18O/16O is large, what is it called?
Heavy
106
If the ratio of 18O to 16O is small, what is it called?
Light
107
What does evaporation preferentially concentrate?
16O
108
What does precipitation preferentially concentrate?
18O
109
When the temperature of water is cooler, what is more concentrated?
18O
110
What happens during glacial periods (18O/16O)?
Increased evaporation and cooler temperatures leave the ocean heavier
111
What is the period of the glacial-interglacial cycle?
100,000 years
112
What is the Milankovitch theory?
Cyclical changes in the Earth's orbit are needed to understand the glacial interglacial cycle
113
What is eccentricity?
The circularity of the Earth's orbit
114
What is the periodicity of eccentricity?
About 100,000 years
115
What is eccentricity currently?
Low
116
What type of eccentricity favors glacials?
High eccentricity, because of effect with precession
117
What is obliquity?
The tilt of Earth
118
What is the period of obliquity?
41,000 years
119
What is the range of obliquity?
22.5 to 24.5
120
What is our current obliquity?
23.5
121
What obliquity factors glacials?
Low obliquity, cool summers = less melting
122
What is precession?
The change of the direction of Earth's axis of orientation relative to the sun
123
What is the period of precession?
23,000 years
124
For a glacial period, what are the ideal conditions?
Mild winters and cool summers, so a small tilt, large eccentricity with a co-occurence with NH summer at aphelion
125
When was the Younger Dryas?
11,640 years ago
126
How long was the cooling of the younger dryas?
8200 year cooling, 400 years long
127
When was the holocene climatic optimum?
10,000 years ago in Alaska, 6,000 years ago North Atlantic
128
When was the medieval climatic optimum?
1000-1300 Ad
129
What was the medieval climatic optimum due to?
Solar and volcanic
130
When was the little ice age?
The late 1500s to the mid 1800s
131
What was the Younger Dryas due to?
A weakening of thermohaline circulation due to glacial melting and freshening of north Atlantic
132
What does the Younger Dryas have to do with Noah's Arc?
Sea level rise from melting ice flooded Lake Euxine, creating the Black sea
133
What was the initial cooling in Greenland/globally due to the younger dryas?
Greenland: 5-9°C; Global: 0.6°C
134
What was the medieval climatic optimum?
A warm period that occurred mainly in the North Atlantic, may have caused Vikings to settle in Greenland
135
How long is the sunspot cycle?
11 years
136
What do more sunspots lead to?
More solar radiation, due to faculae
137
What was the Maunder Minimum?
A period from about 1650 to the early 1700s where there were no/very few sunspots, coincides with little ice age
138
How can volcanoes impact climate?
Enhance or reduce el niño, reduction of diurnal cycle, summer cooling of NH tropics and subtropics, reduced tropical precipitation, ozone depletion, global cooling, stratospheric warming, and winter warming of NH continents
139
What did the volcanic explosion at Tambora lead to (along with an explosion from an unknown volcano) in 1816?
The Year without a Summer
140
When was there a high frequency of volcanoes?
1250-1500, and 1550-1700, coinciding with LIA
141
When was there a low frequency of volcanoes?
1100-1250, coinciding with medieval climatic optimum
142
What causes climate change (not human caused)?
The sun, orbital positions of earth, volcanoes, tectonic processes, greenhouse gases, aerosols, THC
143
What does the ozone do?
Absorb ultraviolet radiation
144
What causes the ozone hole?
CFCs
145
How much has the Earth warmed?
1.09°C
146
How do we know climate change is human caused?
The rate of warming is unprecedented in at least the last 2000 years
147
What is greenhouse gas warming partly masked by?
Aerosol cooling
148
What is the main emission scenario used?
RCP 4.5
149
What level of warming might be associated with RCP 4.5?
2.5°C
150
How much might sea levels rise in RCP 4.5?
.4 m
151
What is positive feedback?
Amplifies original disturbance
152
What is negative feedback?
Dampens original disturbance
153
Do clouds lead to positive or negative feedback?
Lower clouds=negative, higher clouds=positive
154
Is water vapor feedback positive or negative?
Positive
155
Is sea ice albedo feedback positive or negative?
positive
156
What are the current levels of CO2?
410 ppm
157
What are the future impacts of global warming?
More extreme weather, reduction of cyrospace, intensification of weather, earlier spring snowmelt, and increased monsoon precipitation
158
What is carbon budget?
The amount of CO2 emissions that could still work towards a goal of a certain temperature
