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Synoptic Meteorology II > GEOGR 5210 Exam I > Flashcards

GEOGR 5210 Exam I Flashcards

1
Q

What does the term “theory” mean in science?

A

Any hypothesis that succeeds in explaining a wide array of observations over a period of time.

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2
Q

What is the difference between weather and climate?

A

climate - broad composite of the average condition of a region
weather - shorter fluctuations in atmospheric conditions on the order of hours, days, weeks, or a few months

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3
Q

How old is the Earth? How do we know that?

A

4.55 billion years ago

We know this by radiometric dating.

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4
Q

What is climate forcing? What are some examples?

A

Climate forcing is a reference to factors that drive or cause changes in the climate system that result in climatic shifts.

Some examples are changes in plate tectonics, changes in the Earth’s orbit, and changes in the Sun’s strength.

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5
Q

What is a climate response? Examples?

A

The results of a climate forcing.

Some examples are changes in atmospheric, changes in ice, changes in vegetation, changes in ocean, and changes in land surface.

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6
Q

How do response times differ? Give an example of a response at a short time scale and at a long time scale.

A

Response times differ due to the specific properties of the substance that is changing.

A fast response is the daily heating and cooling of the atmosphere. A slow response is the advances and retreats of glaciers.

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7
Q

Does the climate system ever reach equilibrium? Why or why not?

A

No. The system is complex and due to the different time scales of climate response, if an equilibrium is reached it will be short lived.

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8
Q

What is climate feedback? Give an example of a positive and a negative feedback in the climate system. Be able to recognize positive and negative feedbacks.

A

climate feedback - processes that alter climate changes that are already underway, either by amplifying them or suppressing them.

An example of a positive feedback is a decrease in the amount of insolation entering the climate system will allow more ice to grow on the surface of the earth, which will reflect even more insolation, propagating cooling.

An example of a negative feedback is chemical weathering. As Earth warms, the atmosphere is able to produce more precipitation which will enhance the amount of weathering, which removes CO2, resulting in cooling.

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9
Q

How does ozone in the upper atmosphere protect us from UV radiation?

A

Energy gets absorbed by an O3 molecule and separates it into O2 and O.

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10
Q

What is latent heat?

A

The amount of heat associated with a phase change.

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11
Q

What is evapotranspiration?

A

evapotranspiration - the process by which water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from plants

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12
Q

What causes atmospheric circulation?

A

Differences in heating from poles to tropics, land to oceans, and surface to top of the atmospheric layer.

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13
Q

Why is there uneven heating of the earth’s surface?

A
  • Unequal radiation on a sphere
  • Tilt of the earth
  • Specific heat of water is much higher than land
  • Albedo differences
  • Sun angle
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14
Q

Where is there a net gain in radiation? Where is there a net loss? Why?

A

The tropics.

The poles.

Poles typically have higher albedos, lower sun angles, less land, etc. Tropics are the opposite.

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15
Q

Be able to explain Hadley cells and trade winds.

A

Wow. Hadley cell.

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16
Q

Why is there lots of precipitation at the equator? Why dry at 30N?

A

Generally low pressure at the equator due to the convergence of the two Hadley cells. Low pressure promotes lifting mechanisms and supports precipitation.

Generally high pressure at 30N due to convergence of Hadley and Ferrell cells. High pressure promotes subsidence mechanisms and suppresses precipitation.

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17
Q

Why does the ocean circulate?

A

To distribute heat from the tropics around the globe.

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18
Q

Where is the “hinge” of thermohaline circulation?

A

Where the majority of the dense water sinks, northern Atlantic near Greenland

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19
Q

What drives the thermohaline circulation?

A

Density differences in water due to temperature and salinity.

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20
Q

What is a climate archive?
In what settings are they found?
How do they record climate?
Give pros and cons of different examples.

A

A type of record that can hold climate information.
They record climate by quantifying climatic indicators like isotopes or fossils and we can deduce information.
Pros - Invaluable direct records of the climate system at that point in time.
Cons - Can be incomplete, can have low resolution, etc.

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21
Q

How are archives dated to produce a chronology?

A

Radiometric dating
Radiocarbon dating
Counting annual layers
Correlating with other climate archives

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22
Q

What is meant by a climate proxy? Be specific.

A

climate proxy - a quantifiable indicator of climate change contained in a climate archive and covering an interval that precedes direct instrument measurements of climate

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23
Q

What is a high resolution climatic record? What is a low resolution?

A

A high resolution record allows fine temporal detail, e.g. a tree ring.

A low resolution record allows low temporal detail, e.g. an ocean sediment core.

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24
Q

What is a climate model?

A

A computer generation of a climate system derived from numerical representations and simulations of real atmosphere processes.

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25
Q

Define insolation.

A

insolation - incoming solar radiation

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26
Q

Define albedo.

A

the decimal fraction or percentage of incoming solar radiation reflected from a surface

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27
Q

Define greenhouse effect.

A

the warming of Earth’s surface and lower atmosphere that occurs when Earth’s emitted infrared heat is trapped and reradiated downward by greenhouse gases

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28
Q

Why SPECIFICALLY is Venus so much hotter than the Earth?

A

Its CO2 enriches atmosphere creates a much stronger greenhouse effect that traps much more heat.

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29
Q

What is a carbon reservoir? How has carbon been exchanged between reservoirs throughout Earth history?

A

A carbon reservoir is an effective place for carbon to be stored in the climate system.
Carbon has been exchanged through volcanic input and chemical weathering.

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30
Q

How does chemical weathering act as a thermostat for Earth’s climate?

A

Chemical weathering is a negative feedback process, tied closely to the availability of the atmosphere to store moisture. If there is warming, the atmosphere can hold more moisture and can precipitate more. All precipitation is slightly acidic and reacts chemically with silicate rock and takes carbon from the atmosphere in the reaction. The reduction of carbon in the atmosphere makes it cooler. The opposite happens in a cooler situation, making the atmosphere warmer.

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31
Q

What is the evidence for, and the hypothesis that, explains Snowball Earth?

A

In a Snowball Earth, most of the available land is covered by ice. Evidence that shows this happened are moraines, loess, U-shaped valleys, cirques, and rocks smoothed and polished by glaciers.
The hypothesis that accounts for Snowball Earth is lowered solar luminosity, low CO2 due to the emergence of shelled organisms, and land mass configuration that did not allow for efficient heat transfer.

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32
Q

What are the two types of crust?

A

Lithosphere and asthenosphere

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33
Q

What types of plate margins interact in Earth’s lithosphere?

A

Divergent boundaries produce ocean ridges.
Convergent boundaries between ocean and continental plates cause the ocean plate to subduct. Convergent boundaries between two continental plates create high terrain.
Transform boundaries happen when plates slide against each other (San Andreas fault).

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34
Q

What is the polar position hypothesis? How well does it work to explain climate?

A

The polar position hypothesis is the hypothesis that ice sheets exist during intervals in Earth’s history when landmasses are moved into polar regions by plate tectonic processes.

It doesn’t work very well at all.

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35
Q

What was Pangaea? What type of climate did it have? What proxy evidence do we find to support this interpolation?

A

Pangaea is the giant supercontinent that existed between 300 and 175 mya and consisted of al landmasses present on Earth.
Pangaea had a dry tropics and subtropics and moist polar branches. The summer hemisphere was warmer than the winter hemisphere. Pangaea also had monsoons.
There is evidence of the aridity in the tropics from evaporite deposits, and evidence of the monsoons are found in red rock beds.

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36
Q

What is the BLAG hypothesis? How does it explain variations in CO2 over time?

A

BLAG is the hypothesis that tectonic-scale climate changes are driven by variation in the global average rate of seafloor spreading, which alter the amount of CO2 introduced in the atmosphere.
It suggests that the higher the rate of seafloor spreading, the lower the amount of CO2 in the atmosphere, and vice versa.

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37
Q

What is the uplift/weathering hypothesis?

A

This hypothesis proposes that chemical weathering is an active driver of climate change, rather than just a passive negative feedback that moderates climate.

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38
Q

How does uplift/weathering explain variations in CO2 over time? What is the role of surface area in the weathering hypothesis?

A

It postulates that in times of active uplift and fresh rock generation, CO2 is sequestered out of the air by chemical weathering at a higher rate and promotes cooling.
Surface area is directly related to the amount of chemical weathering that occurs.

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39
Q

What is the climatic significance of the Himalayas and Tibetan plateau?

A

The Earth returned to a icehouse phase after the formation of this geologic feature.

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40
Q

Why do we know so much more about Cretaceous climate than previous climates?

A

Proxies fall off and are not as highly resolved before the Cretaceous period.

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41
Q

What evidence exists that suggests what Cretaceous climates were like, and that they were produced by high concentrations of CO2 in the atmosphere?

A

A big indicator is the stomata of leaves during this time period. If there is a lot of available CO2, there is not a need for a lot of stomata.

42
Q

What factors can produce sea level change?

A

Changes in the volume of ocean ridges, collision of continents, transfer of continental sediments to the ocean, water stored in ice sheets, and thermal expansion and contraction of sea water.

43
Q

What evidence supports an asteroid impact 65 mya? How did this impact affect climate on the short and long term? Be specific.

A

Evidence includes the worldwide distribution of a thin layer of sediment enriched in iridium, and element that is rare on Earth but abundant in space.
Instantaneous effects include shock waves that vaporized water and rock and caused tidal waves and firestorms. Short term, soot and dust were lofted to the stratosphere, causing cooling. Longterm this caused higher levels of CO2 and warming.

44
Q

Why did the Earth get briefly even warmer during the Paleocene-Eocene?

A

Breakdown of the thermohaline circulation.

45
Q

What is icehouse Earth? What is greenhouse Earth? Which one are we in now? Why?

A

Icehouse Earth is a phase of the Earth in which ice is present. Greenhouse Earth is a phase in which ice is not. We are currently in Icehouse Earth because ice is present.

46
Q

Beginning in the Eocene, how did Earth’s climate change between 50 mya the past ~2 mya?

A

General cooling, which a sharp cooling around 35 mya, then a constant state, and another sharp cooling at 15 mya, then another constant state.

47
Q

How do ratios of oxygen isotopes work as a paleothermometer and as an indicator of global ice volume? Where/how are these data archived? Be specific.

A

Oxygen has two primary isotopes, O16 and O18. O16 is lighter than O18 and preferentially evaporates. If ice is stored on the Earth’s surface, this is primarily O16, meaning there is a deficit in the oceans. If ice is stored on the Earth’s surface, this means that it is cooler. Therefore, it is a paleothermometer because if this ratio is greater, the temperatures are generally cooler.
These data are archived in foraminifera plankton in ocean sediment cores.

48
Q

What is the Gateway hypothesis? How do changes in these gateways explain global cooling? Is this a good explanation?

A

The Gateway hypothesis focuses on narrow passages that allow or impede exchanges of ocean water between ocean basins. They have proposed that changes in key gateways caused glaciations by altering the poleward transport of heat or salt.
No.

49
Q

What is the ocean heat transport hypothesis?

A

The hypothesis that changes in the amount of heat transported toward polar regions by the ocean cause changes in polar climate.

50
Q

What is the main driver of climate on tectonic scales?

A

Changes in CO2.

51
Q

What is the best explanation for the past 50 myrs of cooling? What two factors could produce changes in CO2? How well do the data support either of these?

A

The Uplift Weathering Hypothesis.
The rate of uplift and rate of weathering.
Relatively well.

52
Q

What causes earth’s seasons?

A

The tilt of the Earth’s axis

53
Q

Be able to define (describe) eccentricity, obliquity, and precession of the equinoxes.

A

Eccentricity - the extent to which Earth’s orbit of the Sun departs from a perfect circle
Obliquity - the extent to which Earth’s axis departs from 0 degrees (range from 22.5-24.5)
Precession of Equinoxes - the absolute motion of the equinoxes and solstices in the larger reference frame of the universe

54
Q

What is the period for eccentricity, obliquity, and precession of the equinoxes?

A

Eccentricity - 100,000 years
Obliquity - 41,000 years
Precession - 23,00 years

55
Q

What are the causes for variations in our orbit?

A

The gravitational pull of other celestial bodies.

56
Q

Explain why we were receiving so much more summer insolation 11,000 years ago.

A

The Earth was at a point in its precession where the summer hemisphere was coincident with perihelion, increasing the insolation.

57
Q

Who was Milutin Milankovitch? What was his contribution to understanding climate change?

A

Milutin Milankovitch was a Serbian astronomer who first calculated in a systemic way the impact of astronomical changes on insolation received on Earth at different latitudes and in different seasons.
His contribution to understanding climate change is that he proposed that orbitally controlled fluctuations in high-latitude solar radiation (insolation) during summer control the size of ice sheets through their effect on melting.

58
Q

What season is most important to the growth and decay of ice sheets?

A

Summer

59
Q

What hemisphere is most important to the growth and decay of ice sheets? Why?

A

Northern Hemisphere, land needed to grow ice.

60
Q

Does ice build or melt more quickly? Why?

A

Ice melts more quickly due to there being more available energy acting to remove ice in a melting scenario vs. the rate at which ice builds (multiple seasons).

61
Q

Where do we get long-term records of greenhouse gas concentrations (what proxy and where geographically)?

A

Ice core concentrations found at the poles

62
Q

How long temporally are ice core records? How do we date them?

A

The records span hundreds of thousands of years.

They can be dated by layer counting, radiometrically, and by ice flow models.

63
Q

Do greenhouse gas records from proxy match recent, instrumental data?

A

Yes.

64
Q

What is the preindustrial range of CO2 concentrations (over the last ~800,000 years?)

A

180-280 ppm

65
Q

What proxy does the CO2 concentrations from ice cores match?

A

Recent and current CO2 measurements

66
Q

What’s the period for glaciations for the last 900,000 years? What about 900,000 to 2 million? Why are they not the same?

A

100,000 years
41,000 years
They are dependent on CO2 thresholds.

67
Q

Why is ice slow to build but quick to melt (relatively speaking)?

A

It is a constant that ice builds over multiple seasons, where ice can melt in less than one season.

68
Q

Where does the CO2 go during glacial periods?

A

Into deep ocean storage

69
Q

Why does the monsoon match methane which follows the precessional signal?

A

More summer insolation -> stronger monsoon -> more moisture -> more standing water -> more methane production

70
Q

Why is the northern hemisphere so important in understanding the Last Glacial Maximum?

A

The Northern Hemisphere has more land on which to grow ice.

71
Q

What was the cryogeography of the LGM? Where were the major ice sheets?

A

Laurentide ice sheet - centered on east-central Canada
Cordilleran ice sheet - over the Rockies in the American west
Scandinavian ice sheet - northern Europe
Barents ice sheet - northern Eurasian continental shelf

72
Q

What was wrong with the glacial chronology developed from the relationships of terminal moraines in North America?

A

Moraines can get erased by other glacial advances/hard to date, etc.

73
Q

How did the Laurentide Ice Sheet affect weather patterns in North America?

A

The ice interrupted the lower-level winds which disrupted the normal path of the jet stream. High pressure system over central ice sheet. Allowed more precipitation in the intermountain west which filled many basins.

74
Q

What/when/how long/how rapid/where were effects felt of the Younger Dryas?

A 
Slower melting of ice sheets and a major cooling in the North Atlantic region
12,000 years ago
Lasted about 1,300 years
Incredibly rapid
All over the world
75
Q

What is hypothesized to have caused the Younger Dryas?

A

Meltwater flooding from glacial lake Aggazi cooling the north Atlantic

76
Q

What evidence has been found to support the hypothesis that glacial lake Aggazi’s drainage caused the Younger Dryas?

A

Records of oxygen and carbon isotopes in the Gulf of Mexico

77
Q

What is the difference between proglacial and pluvial lakes? Give an example of each.

A

proglacial - a short-lived lake that develops after the retreat of an ice sheet in the bedrock depression left by the weight of the ice
pluvial - form in closed drainage basins during periods of differing climate regimes

78
Q

What is isostatic rebound and what does this have to do with deglaciation?

A

Isostatic rebound is the slow return of rock to fill a basin. The rock was displaced by the weight of an ice sheet. This only occurs after deglaciation.

79
Q

What is the Holocene Thermal Maximum? What caused it? What evidence is there for it?

A

The Holocene Thermal Maximum is a jump in temperatures caused by the Holocene Insolation Maximum. Evidence is found in pollen.

80
Q

What is ice rafted debris? What can we learn from it?

A

Ice rafted debris is sediments of widely ranging sizes eroded from the land by ice, carried to the ocean, and deposited on the seafloor. We can learn how currents were moving a particular time in Earth history.

81
Q

Was the Little Ice Age a local, regional, or global event? Describe some evidence that supports this view. What factors may have caused it?

A

It seems that the Little Ice Age was a global event, but it’s extent was much bolder in Europe than any other place. There are sketches and letters of people living in the Alps who had to leave their homes to evacuate advancing ice. Some scientists pose that this is due to the Maunder Minimum.

82
Q

Explain the difference between the following measures of climate change over time: 1) instrumental records, 2) high resolution proxy measurements, and 3) low resolution proxy measurements.

A
  1. Don’t go back very far in time but are extremely precise
  2. Useful for time periods in which instrumentation was unavailable
  3. Main advantage over long time periods
83
Q

What are some of the physical processes that we monitor to understand the direction and pace of anthropogenic climate change? What are some of the biological indicators? Give examples of both.

A

Physical processes - warming, decreasing ice expanse, rising sea level
Biological indicators - migration patterns of animals, extinctions

84
Q

What methods do we use to predict the future of anthropogenic climate change? What limitations do these methods have?

A

Climate models.
These models are not a sum of its parts. There are feedbacks that even the most sophisticated models cannot capture, making the predictability of our climate capped.

85
Q

Why is the arctic responding so dramatically to greenhouse warming? Why is the Antarctic not responding in the exact same fashion?

A

Ocean currents. There is more land based ice in the Antarctic which makes it less susceptible to warmer ocean currents. Also, the invigorated hydrologic cycle is putting more ice down in the Antarctic than the arctic.

86
Q

When talking about recent climate change, what two facts are indisputable?

A

Greenhouse gases from the burning of fossil fuels are accumulating at an unprecedented rate
Global average temperatures have increased by 1 degree Celsius in the last 100 years

87
Q

What are the relative abundances of CO2 and CH4 during: 1) glacial maxima, 2) interglacial periods, 3) now.

A

1) 190 ppm - CO2, 350 ppb - CH4
2) 280 ppm - CO2, 700 ppb - CH4
2) 400 ppm - CO2, ~2000 ppb - CH4

88
Q

What effect could sulfate aerosols be having on global climate? What is the implication of this effect on the pace of greenhouse gas warming?

A

Sulfate aerosols could be mitigating the true effect of anthropogenic climate change. By removing these aerosols through anti-pollution initiatives, the planet could be “warming” much faster than has been previously observed.

89
Q

Describe the trends in average global temperature over: 1) the past 1000 years, 2) the past 140 years. How well do model outputs match with this data?

A

1) Not much variation
2) About 1 degree of warming

Match relatively well

90
Q

When discussing the “uncertainty of the impacts of humans on future climate, what are the two “known unknowns”?

A
  1. Future emissions

2. Climate sensitivity

91
Q

What is the range of average global temperature increase from model output? What factors that we cannot know about affect the range of these results?

A

2-10 degrees of warming

Climate sensitivity and future emissions

92
Q

What time lag factors must be included in any prediction on future anthropogenic climate change?

A

The thermal lag that is inherent in CO2 gas, as well as the lag from insolation.

93
Q

Can we count on natural climate change to negate the effects of human activities? Why or why not?

A

Of course not. Humans are using much more energy per capita than the Earth is receiving. It’s an energy imbalance.

94
Q

What factors will cause sea level rise in a greenhouse warmed world?

A

Ice melt and thermal expansion

95
Q

What are the key uncertainties in predicting the pace and extent of global climate change due to human activities?

A

Population growth, rate of emissions, climate sensitivity, etc.

96
Q

Why should we try to limit temperature increases below 2 degrees? What are the feedbacks that might cause runaway greenhouse warming?

A

This keeps our climate from triggering a carbon cycle feedback that could cause runaway global warming. Another feedback is Siberian permafrost melt.

97
Q

What are the warming implications of global dimming?

A

Global dimming has diminished the true effect of global warming, should expect more temperature increase as pollution goes down.

98
Q

How might global dimming have caused the drought in Ethiopia in the 1980s?

A

Pollution from Europe and N. America disrupted the seasonal monsoon and it didn’t hit Ethiopia which threw off drought patterns.

99
Q

List three sources of CO2.

A

Cars, industry, humans.

100
Q

List two sinks of CO2.

A

Ocean and vegetation.

101
Q

List two sources of CH4.

A

Agriculture and anaerobic decomposition.

102
Q

List two sinks of CH4.

A

Ocean and sediments.

Synoptic Meteorology II (2 decks)

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