Unit 3 Test

Question 1

What is the typical lifecycle of a single-cell thunderstorm?

Answer 1

Approximately 30 minutes

Question 2

What is a downdraft and why does it occur?

Answer 2

Rapidly sinking air caused by precipitation, which helps cut off the rising motion of single-cell thunderstorms

Question 3

What is a mesoscale convective system?

Answer 3

Group of “cells” of thunderstorm, with each being from 30-60 minutes and the whole system lasting several hours, which is overall typically more intense than a single-cell thunderstorm

Question 4

What are the two types of mesoscale convective systems?

Answer 4

Squall-lines and mesoscale convective complex (MCC)

Question 5

What is a squall-line?

Answer 5

A line of thunderstorms formed along or out ahead of a cold front

Question 6

What is a mesoscale convective complex (MCC)?

Answer 6

A circular-shaped, self-sustaining system of thunderstorms

Question 7

Why are tornadoes so common in the central and southern US?

Answer 7

We have all the “ingredients” - weather systems with fronts, unstable air, and lots of vertical wind shear

Question 8

What time of the year do tornadoes most frequently occur?

Answer 8

March-June

Question 9

How does hail form?

Answer 9

1. A frozen water droplet is swept up by currents within a thundercloud
2. Supercooled moisture freezes onto the droplet’s surface forming a layer of ice
3. As it gets heavier, gravity pulls it downward
4. Then it’s sucked back up by strong updrafts
5. As the process continues, thick layers of ice accumulate on the hailstone’s surface
6. Eventually, gravity pulls the hail through the warm, wet cloud base and finally to the ground

Question 10

What are the stages involved in lightning formation?

Answer 10

1. Potential difference - A buildup of negative charge at the base of a thundercloud creates a positive charge region on the ground
2. Stepped leader - A channel of negative charge moves from the cloud to the ground in a series of steps
3. Streamer formation - Positive charges move upward from the ground toward the cloud
4. Return stroke - The stepped leader and streamer meet, creating a conductive channel that allows a large electric current to flow from the cloud to the ground, which is the visible lightning flas
5. Short circuit - The high-temperature conducting channel short-circuits to the ground
6. Final stage - The channel continues to transfer charge to the ground, but less intensely

Question 11

Describe the spiral rain bands of tropical cyclones?

Answer 11

Curved bands of clouds and thunderstorms that trail away from the eye wall in a spiral, often producing heavy rain and wind, or even tornadoes

Question 12

Describe the eye of tropical cyclones?

Answer 12

The center of the storm, which is an area of sinking air and light winds, making up the calmest part of the storm

Question 13

Describe the eye wall of tropical cyclones?

Answer 13

An area around the eye of the storm consisting of a ring of tall thunderstorms producing heavy rain and the strongest winds

Question 14

Why is the front right quadrant of a hurricane important?

Answer 14

High wind speeds, storm surge, and tornadoes are all maximized in this area

Question 15

What is storm surge and where is it the greatest?

Answer 15

Ocean waters that pile up ahead of the hurricane due to the storm’s net winds, which is greatest to the right of where the winds are the greatest

Question 16

How do volcanoes impact climate over the short term?

Answer 16

Atmospheric cooling due to the injection of aerosols, which raise global albedo, reflecting solar radiation into space and cooling for a year post-eruption

Question 17

How do volcanoes impact climate over the long-term?

Answer 17

The long-term effect is warming because volcanoes do emit greenhouse gases (but they aren’t a significant contributor to current climate change)

Question 18

How does solar output impact climate?

Answer 18

Earth’s temperatures are linked to variations in the amount of energy emitted by the Sun, reflected in sunspot activity, but this has been declining in recent decades even as temperatures continue to rise, so it is not a cause of global warming

Question 19

What are the two Milankovitch cycles?

Answer 19

Eccentricity and precession

Question 20

What is eccentricity Milankovitch cycle?

Answer 20

Describes variattions in how elliptical Earth’s orbit is, which varies in ~100,000 year cycles. Low eccentricity = little variation in the earth-sun distance; high eccentricity = up to 20% difference in solar radiation between perihelion and aphelion

Question 21

What is precession Milankovitch cycle?

Answer 21

Describes the wobble of Earth’s axis like a top, which varies in ~26,000 year cycles. Currently, the Northern Hemisphere is tilted away from the sun during the perihelion [closest point in orbit to sun]; eventually the Northern Hemisphere will point toward the sun during the perihelion

Question 22

How is the recent period of global warming different than past periods of warming, and how do we know it’s not due to the discusses natural sources of climate change?

Answer 22

Our climate has changed before, but our role is new. Based on Milankovitch cycles, we should be starting a long, gradual decline into another ice age, and natural sources of climate variability do not account for this warming trend

Question 23

What is the cause of the recent period of global warming?

Answer 23

The main cause is humans changing the atmospheric composition since the Industrial Revolution by adding greenhouse gases

Question 24

Who was Eunice Foote?

Answer 24

She first saw the effects of selective absorption by greenhouse gases (in 1856)

Question 25

Who was John Tyndall?

Answer 25

He first documented the effect of greenhouse gases by capturing gas emitted during the combustion of coal in a glass tube and finding that it was a powerful absorber of infrared energy (in the 1860s)

Question 26

Who was Svante Arrhenius?

Answer 26

He calculated the influence of CO2 emissions on global temperature (doubling of CO2 leading to an increase of 5 degrees C; today's estimate is closer to 1.5-4.5 degrees C), thinking it would be beneficial to warm colder regions (in the 1890s)

Question 27

What is a positive feedback loop?

Answer 27

Increases the initial change, moving away from equilibrium and producing instability (ex: ice-albedo and water vapor feedback)

Question 28

What is a negative feedback loop?

Answer 28

Decreases the effect of change, moving away from equilibrium and maintaining instability (ex: regulation of temperature through cloud cover)

Question 29

How has the sea level changed in recent decades, and why?

Answer 29

Has increased by ~4 inches since 1993 due to the melt of grounded ice (glaciers + ice sheets) and the subsequent runoff

Question 30

What are the leading sources of anthropogenic greenhouse gases?

Answer 30

Mainly due to the use of fossil fuels due to cars, heating buildings, and power factories

Question 31

Which economic sectors contribute the most to global emissions?

Answer 31

Transportation, electric power, and industry

Question 32

What are the nuances of which countries contribute the most to greenhouse gas emissions?

Answer 32

China looks to lead it by far, but looking by capita is actually in 7th place, with US, Canada, and South Korea leading. Much of China's carbon emissions are also to satisfy the "appetite" of western countries

Question 33

Define uniformitarianism?

Answer 33

The same physical processes active in the environment today have been operating throughout geologic time; "The present is the key to the past"

Question 34

What are endogenic processes?

Answer 34

Encompasses internal processes that produce flows of heat and material from deep below Earth's crust; radioactive decay is the main energy source (Ex: tectonics, earthquakes, and volcanism)

Question 35

What are exogenic processes?

Answer 35

Involves external processes that set into motion air, water, and ice, all powered by solar energy (Ex: Rivers, landforms, weathering, erosion, oceans, and glaciers)

Question 36

What is the order of the Earth's interior layers?

Answer 36

Inner core, outer core, mantle, crust (innermost to outermost)

Question 37

Describe the pattern of density of the layers of the Earth's interior?

Answer 37

The inner core is extremely dense, with density decreasing as you move outward

Question 38

Are the layers of the Earth's interior liquid or solid?

Answer 38

Inner core - solid, outer core - liquid, mantle - solid, crust - solid

Question 39

What is responsible for the generation of the Earth's magnetic field?

Answer 39

The outer core, which flows as the Earth spins, generates the Earth's magnetic field because it is made of liquid molten metallic iron. Its strength and orientation vary, and it reverses itself every ~500,000 years

Question 40

What is the lithosphere?

Answer 40

Made up of the crust and uppermost mantle, is 50-100 km thick, and litho = rock because it's brittle and "breaks"

Question 41

What is the asthenosphere?

Answer 41

Only the mantle, is ~250 km thick, and astheno = "w/o strength" because it's ductile and bends

Question 42

What are minerals?

Answer 42

Naturally occurring, inorganic, solid, crystalline structure, and definite chemical composition

Question 43

What are rocks?

Answer 43

Naturally occurring aggregates of minerals (1 or more)

Question 44

What are the three main rock types and their subtypes?

Answer 44

Igenous (extrusive or intrusive), sedimentary (clastic or chemical), and metamorphic

Question 45

How are igneous rocks formed?

Answer 45

From molten rock which becomes magma

Question 46

What's the difference between extrusive and intrusive igneous rocks?

Answer 46

Extrusive rocks form at the surface due to eruptions and volcanic activity, are fine-grained, and cool rapidly, while intrusive rocks are formed underground, are coarse-grained, and cool and solidify more slowly

Question 47

How do sedimentary rocks form?

Answer 47

Through lithified sediment; composed of grains

Question 48

What's the difference between clastic and chemical sedimentary rocks?

Answer 48

Clastic are formed from particles (or clasts) that are eroded from other rocks and deposited (can range anywhere from coarse to fine), while chemical are formed from minerals precipitated from solution, which occurs in bodies of water, such as lakes or oceans

Question 49

How do metamorphic rocks form?

Answer 49

Recrystallization of other igneous, sedimentary, or metamorphic rocks to a different mineral structure under great heat and pressure; higher density; more resistant to weathering

Question 50

What is foliation?

Answer 50

A repetitive layering pattern of buildup seen in metamorphic rocks

Question 51

What are the evidences of plate tectonics and how do they support the theory?

Answer 51

Signs of continental drift are seen in how continent shapes fit together like a puzzle and alignment of fossils across continents

Question 52

What type of earthquake activity is associated with subduction zones?

Answer 52

The deepest earthquakes occur along subduction zones, and we can see a progression from shallow to deep earthquakes along subduction zones

Question 53

What is rifting?

Answer 53

Rifting is the extension/spreading of plates (divergent plate boundaries)

Question 54

What landforms are associated with continental and oceanic rifting?

Answer 54

Oceanic rifting creates mid-ocean ridges, while continental rifting creates valley dividing continents and new ocean basins

Question 55

At what plate boundaries does subduction occur?

Answer 55

Subduction occurs at oceanic-oceanic and oceanic-continental convergent plate boundaries (very little or none at continental-continental convergent)

Question 56

What features are present along subduction zones?

Answer 56

One plate being pulled under another is what occurs along subduction zones, along with deep earthquakes. Oceanic-oceanic creates ocean trenches and volcanic activity above surface, and oceanic-continental creates volcanic activity on land

Question 57

Is there volcanic activity at subduction zones and, if so, what type (effusive vs explosive)?

Answer 57

Volcanic activity is present at rifting/subduction plate boundaries, specifically explosive types (the typical volcano type you think of – more explosive; forms new continental ground; steep-sided volcanoes due to interlayered ash and lava; pyroclastic flow and lahars)