Units 30-31 Flashcards
What is the key agent in modifying Earth’s surface?
Water
True or False: The role of water is simple but the behavior of water is complex
True
Hydrological cycle
The movement of water through various reservoirs on or near Earth’s surface
Reservoir
A place or state where water can reside within the Hydrological sytem
What is the most important reservoir of fresh water for human use?
Groundwater
What drives the hydrological cycle?
Solar heating
Transpiration
water that evaporates out of plants
Residence time
The average amount of time water spends within a reservoir
Stream
A conduit through which surface water moves, either constantly or intermittently.
It is any system of flowing surface water with a headwater and an endpoint.
Stream gradient
The slope of the terrain over which a stream flows
Base level
The elevation of a stream end point
True or False: As the velocity and volume of a stream goes up, the capacity of the stream to carry sediment increases.
True
True or False: There is more sediment carried by stream runoff during Spring than in the Fall (melting snows)
True
Equilibrium profile
The slope at which sediment is transported
Alluvial fan
Sediment and debris at the mouth of a canyon deposited by intermittent water flow
Delta
Sediment and debris deposited in an ocean or lake at the mouth of a river
Floodplains
Plains intermittently covered with water from a flooding river.
True or False: A drop in base level causes down cutting by a stream
True
True or False: A relative rise in base level causes sediment to be deposited
True
When will sediment be deposited by a stream?
Wherever and whenever the velocity of water is too slow to carry the sediment in the stream.
What are three examples of places / circumstances when sediment is deposited by a stream?
- Alluvial fans
- Deltas
- Floodplains
Where do alluvial fans form most readily?
In arid mountainous regions
Why do alluvial fans form in arid mountainous regions?
Because mountains provide the steep gradient for rapid flow. Aridity prevents permanent streams from forming.
True or False: Deltas are some of the most rich, fertile places on earth and are typically places where humans have settled
True
Zone of accumulation
The region of a glacier where snow accumulates
Zone of ablation
Region of a glacier where snow and ice decrease by melting, sublimation, or calving
Alpine glacier
A glacier formed in a mountain valley
Continental glacier
Glacier covering a large portion of a continent or land mass
Moraine
Rock and sediment carried by a glacier
Till
Moraines left in the zone of ablation
Why do glaciers form?
Because snowfall exceeds summertime evaporation and melting
Calving
Where large blocks of ice break off of a glacier
How do icebergs form?
When glaciers calve into the ocean
Why do glaciers “flow”?
Because the zone of accumulation exceeds a certain weight. They are usually in mountains anyway, so gravity is helping.
True or False: Glaciers need to be on a hill to flow/move.
False
When would a glacier flow horizontally?
When it is moving from an area of high pressure to low pressure
True or False: Glaciers can flow uphill
True
Does ice have elastic or plastic properties?
Both
What is the difference in sedimentary deposit behavior of a glacier and a stream?
Streams: transport smaller sedimentary particles farther than large particles
Glacier: transport particles of various sizes the same distance
Which presents more pressure on bedrock, glaciers or streams? What does this result in?
Glaciers
They pick up rocks and drag them along the bottom, SCOURING the bedrock
Porosity
The percentage of empty spaces in a rock that water can occupy
Permeability
A measure of how easily water can flow THROUGH rock or sediment
Water table
the depth in the ground where rock is saturated with water
Aquifer
A ground layer saturated with water and having sufficient porosity and permeability to supply groundwater to a well or spring
Aquitard
A ground layer saturated with water and lacking sufficient porosity and permeability to supply groundwater to a well or spring
Fun Fact: Antarctica is covered in continental glaciers that are 3500 meters thick in some places
WOAH
True or False: Groundwater resides in underground pools or lakes
FALSE
Does water flow more easily through rocks of high or low permeability?
High
True or False: High permeability and high porosity OFTEN go hand in hand
True
True or False: Despite its high porosity, clay is almost always an aquitard.
True
Recharge
Water that soaks into the ground replenishing the groundwater reservoir
Discharge
Water released from a groundwater reservoir
Gaining stream
A stream whose volume of flowing water increases from groundwater discharge along its channel
Losing stream
A stream whose volume of flowing water decreases as stream flow is lost to groundwater recharge along its channel
Where does groundwater originate?
Snow and rainfall
In a gaining stream, is the water table above or below the water line?
Above
In a losing stream, is the water table above or below the water line?
Below
Why does water flow into a stream (gaining stream)?
The fluid pressure in the aquifer is higher than in the stream. Fluids flow from regions of high to low pressure, so water migrates into the stream.
True or False: In streams, water flows from the ground to the stream, not only from runoff.
True
Cone of depression
A region next to a well or source of discharge where the water table is lowered.
Downcutting
The erosion of the base of a stream until the stream reaches its equilibrium profile.
Equilibrium profile
The slope of a stream at which sediment is transported instead of deposited and eroded.
Slope retreat
The erosion of the sides of a stream.
Intermittent streams
Watercourses that only carry water during flashfloods
True or False: Although some of the rocks at the bottom of the grand canyon are 2 billion years old, the process to form the grand canyon took only 4 million yearsish
true
True or False: The Colorado river carved the grand canyon on its own
FALSE
Why is the Grand Canyon so wide in some areas?
Because of side streams and tributaries from the main Colorado river, carving out their own canyons
Which erodes faster, sediment or bedrock?
Sediment
Where does the stream flow the fastest, in the middle or on the sides?
Middle
What shape valley is formed by alpine glaciers?
U-shaped
What shape valley is formed by streams?
V-shaped
True or False: Moraines are characterized by angular and unsorted debris
True
How are sinkholes and caverns formed?
Water dissolving certain kinds of rock, like limestone
Climate
The historic cycle of weather patterns. The generally prevailing weather conditions throughout the year. The expected or average weather conditions.
True or False: Climate changes abruptly
False (but weather can)
What are the five types of climates in Koppens climate system?
- Humid tropical
- Dry
- Humid mid latitude with mild winters
- Humid mid latitude with severe winters
- Polar
What is a humid tropical climate?
Warm places that NEVER experience cold temperatures. Temps average well above freezing all year long.
What is a dry climate?
Places where water is always deficient because evaporation and transpiration rates are greater than precipitation rates.
What is a humid mid-latitude with mild winters climate?
Places with average temps below 64 degrees F but above 27 degrees F
What is a humid mid-latitude with severe winters climate?
Places with mean temperatures above 50 degrees F but with the coldest monthly averages below 27 degrees F
What is a polar climate?
Places that never experience warm summers. All months are below 50degrees F
Examples of local influences that affect climate (other than the location that place is on the earth):
- Land and water
- Prevailing winds
- Mountains and highlands
- Ocean and air currents
- Pressure and temperature
True or False: Land gains and loses heat faster than water
True
True or False: Temperature variations are much greater over land than over oceans or large lakes
True
Why do places farther from water have colder winters and hotter summers?
Because they are on the land, where temperature variations are larger. Land gains and loses heat faster than water. Water locations regulate temps better.
How do prevailing winds affect local climate?
Winds blowing air in from the ocean bring moisture with it. Winds that blow air out TO the ocean take moisture, leaving that area dry.
Why are mountains and highlands important to climate?
They promote rainfall and moisture
How do ocean and air currents affect local climate?
Convection currents carrying warm water to colder regions and cold water to warmer regions, moderating their temps.
Is El Nino cold or warm?
Warm
Is La Nina cold or warm?
Cold
Is earth in a warming or cooling period?
Warming
What is a temperature proxy?
The way we look at approximate temperatures of ancient dates to see what our ancient climate has been like.
Examples of temperature proxies:
- Width and characteristics of tree rings
- Chemical abundance in snow, corals, and stalactites
- Recorded histories of sea ice melting and crop harvest times
- Isotope analysis (for much farther dates), usually oxygen
- Ice cores - for millions of years
What is “eccentricity”
The amount that Earth’s orbit varies from being circular (and becomes more elliptical)
When does earth’s climate vary more, during a circular or elliptical orbit?
Elliptical
Milankovitch Cycles
The name given to the three cycles in Earth’s orbital conditions that influence climate on regular intervals of 100,000-year, 41,000-year, and 23,000-year cycles.
What is a positive feedback?
Turns a small temperature change into a larger one. Amplifies the influence a small temperature change has on the environment.
A small temp drop causes land masses to be covered with ice, which in turn reflects more sunlight back into space without heating up. As a consequence, the global temp is lowered further, more snow and ice accumulates, and the temp drops even more.
What is a negative feedback?
The opposite of a positive feedback. Reduces the temp drops/changes.
Minimizes the influence of a temperature change on the climate.
Greenhouse gases
Gases in the atmosphere that trap heat and keep earth warmer than it would otherwise be.
What are the 4 most important greenhouse gases?
- Carbon dioxide
- Methane
- Nitrous oxide
- Water vapor
True or False: Greenhouse gases are significant temperature regulators
True
black-body radiation
Electromagnetic radiation given off by all objects with a temperature above absolute zero.
It is the continuous light spectrum emitted by a hot, dense object. Hot = above absolute zero.
In other words, all things in the universe glow to some degree
Greenhouse effect
Short wavelength light from the sun is transmitted through the atmosphere warming the earth’s surface.
Long wavelength light (infrared,heat) from the EARTH is absorbed by greenhouse gases in the atmosphere.
This prevents heat from escaping , increasing earth’s temp.
How much visible and near UV light from the sun are reflected back by snow, ice, and clouds?
About 30%
What wavelengths/light is captured by greenhouse gases?
Black-body radiation coming from the earth
True or False: Rotting vegetation creates methane
True
True or False: Rotting vegetation producing methane is an example of positive feedback
True
What type of feedback is represented by high levels of water vapors creating more clouds that prevent sunlight from reaching earth’s surface?
Negative
True or False: When the earth’s temperature gets warmer, it encourages an even higher number of CO2 and CH4 emissions, which is a positive feedback
True
True or False: Negative feedback is an effect caused by changes in climate that decreases how much the climate responds to the change.
True
True or False: Positive feedback is an effect caused by changes in climate that increases how much the climate responds to the change.
True
What happens during the first 100,000 year cycle of the earth’s orbit?
It goes from a circular orbit to an elliptical one. This changes the sunlight distribution and heat affecting earth in different parts of the orbit.
What happens during the second 41,000 year cycle of the earth’s orbit?
The earth goes from a large tilt to a smaller tilt (by about 3)
What happens during the third 23,000 year cycle of the earth’s orbit?
the axis points change as the earth’s rotation on its axis is uneven.
