Geoscience 40 Exam 3
Geostrophic gyres
(geos, "earth"; strophe, "turning"), gyres in balance between the pressure gradient and the Coriolis effect, and their currents are geostrophic currents
Tidal range
(high-water to low-water height difference) varies with basin configuration
Neap tides
(noepa, "hardly disturbed") occur when the moon, earth, and sun form a right angle.
Thermohaline currents
(so named because they depend on density differences caused by variations in water's temperature and salinity) are the slow, deep currents that affect the vast bulk of seawater beneath the pycnocline
In a simplistic system, we think of the solid Earth rotating through an ellipsoidal envelope of ocean water
- 1 full rotation takes the Jersey Shore through 2 bulges every 24 hours - Leading to 2 tides per day
If inputs - outputs - balance is positive
- Accretion of deposition - Coast builds out
What is the earth's velocity halfway between the north pole and the equator in km/hr?
- At 45 degrees North latitude, the circle's radius and circumference are half that of the equator - So speed at 45 degrees North latitude is half that at the equator
Surface occurs when d < L/2
- Bottom of wave hits shore bottom - Bottom of wave slows down from friction - Wave height increases - Wave topples over as a breaker in surf
Tidal drag slows down the earth's reaction
- Cambrian (560 Ma): 425 days - Permian (280 Ma): 395 days - Today (0 Ma): 365 days
Impacts of El Nino
- Climate changes are global - Hot and dry in southeast Asia - Leads to droughts and famine - Wet along west coast of north America - Leads to storms and mudslides
Overfishing
- Marine sources account for 17% of total animal protein consumed by humans - 90% of worldwide stocks of tuna and cod have disappeared - 30% of marine fisheries overexploited - Not enough breeding stock to replenish species - 57% at limit of exploitation
In comparison, the total amount of energy that all humans use in a year is
4.1 x 10^20 Joules.
Antarctic bottom water has been identified as high as
40 degrees north latitude on the Atlantic floor, a journey that has taken some 750 years
Earths circumference
40,010 km
Each hour
430 quintillion Joules of energy from the sun hits the Earth. That's 4.30 x 10^20 Joules.
In theory, the direction of Ekman transport is
90 degrees to the right of the wind direction in the Northern Hemisphere and 9- degrees to the left in the southern hemisphere
La Nina
("the girl"), contrasting colder-than-normal events
The berm (or berms)
An accumulation of sediment that runs parallel to shore and marks the normal limit of sand deposition by wave action
Normal flow
La Nina
Positive numbers mean that the eastern Pacific is warm and negative numbers mean the eastern pacific is cold. Are we in an El nino or La nina today?
La nina
Oceanic eddies can be generated by anything that perturbs
Laminar flow
Interactions between wind and water are complicated by
The fluidity of water
Wavelength
The horizontal distance between two successive crests (or throughs)
Currents
The horizontal drift of ships and the vertical movement of cold water toward the ocean's surface are caused by the mass flow of water
Storms can affect tide height
Meteorological tide
Weather-related alterations are sometimes called
Meteorological tides after their origin
Coriolis deflections in northern and southern hemisphere are
Mirror images of each other
The tidal pattern is called
Mixed (or semidiurnal mixed) if successive high tides or low tides are of significantly different heights throughout the cycle
Equatorial upwelling
Occurs in these westward flowing equatorial surface currents
Atmospheric flow and
Ocean currents are linked
Gravitational forces from moon and sun attract
Ocean waters
Beach nourishment
The importation of sand trapped behind dams (or from other sources) is also only a temporary and very expensive measure
Gravity waves
The inertia of the water causes the crests to overshoot and become troughs
The location of a coast depends
Primarily on global tectonic activity and the volume of water in the ocean
The phenomena of the Southern Oscillation and El Nino are coupled
So the terms are often combined to form the acronym ENSO, for El Nino/Southern Oscillation
In the northern hemisphere, a south-to-north wind leads to an easterly Coriolis deflection
So water piles up against a coast to the east.
First, the wind must be moving faster than the wave crests for energy transfer from air to sea to continue
So, the mean speed, or wind strength, of the wind is clearly important to wind wave development
The primary driver of thermal energy exchange between the ocean and the atmosphere is
Solar radiation
Waves are energy cycles in motion
Sometimes it is useful to think of wave cycles rather than wave distances
As a rule of thumb, if you want to know the weather in state college tomorrow, find out what the weather today is
Chicago
Although the Coriolis effect is weak near the equator (and absent at the equator)
Water moving in the currents on either side of the equator is deflected slightly poleward and replaced by deeper water
Which of the following reflects the time that it takes for a wave cycle to pass?
Wave period
Celerity
Wave speed in distance / time units
During their formation, moderate-sized wind waves in the open ocean exhibit a maximum
Wave steepness (ratio of wave height to wavelength) and angle of their crest
Gradual slope
Waves "spill"
Wave motion can be modeled by sine waves
Waves are generated by disturbing forces and by restoring forces
No matter at what depth water masses are located, the characteristics of each are usually determined by the
Conditions of heating, cooling, evaporation, and dilution that occurred at the ocean surface when the mass was formed
Well-mixed estuaries
Contain differing mixtures of freshwater and salt water through most of their length
Ocean currents are stratified on the basis of density. Are the most dense layers at the ocean surface or the ocean floor
Dense currents are at ocean floor
Winds drive surface currents in oceans. What guides the movement of deep ocean currents?
Density differences
Barrier islands
Depositional coasts can also develop narrow, exposed sandbars that are parallel to but separated from land
Highest tides occur when moon and sun are aligned
Spring tides
When earth, moon, and sun are aligned - biggest tides
Spring tides
Deep ocean currents
Stable stratification of 5 deepwater currents
Storm surges are sometimes even called
Storm tides when the volume of water they force onshore is greatly increased if the surge arrives at the same time as a high tide
Irregular longshore bars
Submerged or exposed accumulations of sand, complete the seaward profile
Laminar flow
Every fluid molecule follows a straight path that is parallel to the boundaries
Turbulent flow
Every fluid molecule follows a very complex path
Equilibrium theory of tides
Explains many characteristics of ocean tides by examining the balance and effects of the forces that allow a planet to stay in a stable orbit around the sun, or the moon to orbit earth.
Jetties or groins
Extensions of rock or other material placed at right angles to longshore drift, to stop the longshore transport of sediments
The result of no thermahaline circulation
Extreme weather variations
Fjord estuaries
Form where glaciers have gouged steep, U-shaped valleys below sea level
A bay mouth bar
Forms when a sand spit closes off a by attaching to a headland adjacent to the bay
Sand spits
Forms where the longshore current slows as it clears a headland and approaches a quiet bay
What is the inverse of period (1/P)
Frequency
Tide-dominated deltas
Freshwater discharge is overpowered by tidal currents that mold sediments into long islands parallel to river flow and perpendicular to the trend of the coast
The Ekman Spiral for winds
From north to south
NASA selected cape Canaveral for rocket launches to
Gain added oomph (=momentum) of southerly location
Wave-dominated deltas
Generally smaller than either tide or river dominated deltas and have a smooth shoreline punctuated by beaches and sand dunes
The effect of Coriolis forces on atmospheric convection generates three convection belts each in the northern and southern atmospheres. From the equator to the north pole, they are:
Hadley, ferrel, polar cells
Air at 30 degrees latitude
Has lost its water to make desert belts
Tidal bore
If conditions are ideal, will form in some inlets (and their associated rivers) exposed to great tidal fluctuation (bara, "wave")
Internal waves
Subsurface waves
Mixed
Successive high and low tides have significantly different heights (double bumps)
The Net Water Transport is the
Sum of all of those currents
Halite
Table salt NaCl
Which two factors are most important in determining the density of ocean water
Temperature and salinity
We sometimes call inertia centrifugal force
The "force" that keeps water against the bottom of a bucket when you swing it overhead in a circle
Why do we not find built-out deltas on the Atlantic coast of the United States?
The Atlantic ocean currents are so strong that they redistribute river sediment before it accumulates in a delta.
Sea islands are composite structures that contain
a firm central core that was part of the mainland when sea level was lower
The net water transport is the
sum of all those currents
Beach scarp
A vertical wall of variable height, often carved by wave action at high tide - to the low-tide mark where the offshore zone begins
The kind of wave is known as an orbital waves
A wave in which particles of water move in closed circles as the wave passes
A beach
A zone of loose particles that covers part or all of ashore
El Nino
- Climate cycle originating in equatorial pacific with global amplification - Likely started at least about 10,000 years ago, based on 13,000 year - old corals - Cayse of major famines in Asia due to failures of monsoonal rains and in south America due to collapse of fishing
In the northern hemisphere, Coriolis Forces lead to
- Clockwise rotation around downwelling and downdrafts - Counter-clockwise rotation around upwelling and updrafts
Consequences of the Ekman spiral
- Coastal winds frictionally move surface layer along coast - Water below upwells to replace advected water - Net flux of upwelled water is away from coastline
The Ekman spiral
- Coriolis forces deflect the surface current created by a northerly wind to the East - And the water beneath the surface current is deflected by Coriolis forces - And the water beneath that current is deflected by Coriolis forces
The ekman spiral
- Coriolis forces deflect the surface current created by a northerly wind to the east - And the water beneath the surface current is deflected by Coriolis forces - The water beneath that current is deflected by Coriolis forces
According to the dynamic theory of tides, since the moon is usually not in the equatorial plane of earth
- Coriolis forces divert tide waves towards the southwest in the southern hemisphere - "no-tide" nodes called amphidromic points occur in each ocean basin
"Boxing Day" Tsunami - Dec. 26, 2004
- Countries most affected: Indonesia, Sri Lanka, Thailand, India - 187,000 dead and 43,000 missing = 230,000 - Second largest earthquake ever recorded --- After 9.5 in Chile on 22 May 1960 - Faulting lasted 500 to 600 seconds --- Longest duration ever observed - Energy released equal to 0.25 gigatons of TNT - Earth's surface oscillated 8-12 inches at epicenter --- About half an inch over whole planet
Earth and moon rotate around this center of mass (like figure-skaters)
- Creates an ocean bulge on the opposite side - Ocean is flung outward because of centrifugal force
3 types of waves defined in terms of relative water depth
- D > L/2 = deep water wave - In between = transitional waves - D < or equal too L/20 = shallow water wave
Waves are defined in terms of depth (d)
- Deep water waves: d > L/2 - Transitional waves: L/2 > d > L/20 - Shallow water waves: L/20 > d
Smoothing rough coastlines
- Deposition in embayment's - Erosion of headlands
ENSO
- El nino - southern oscillation - Variations in the temperature of the equatorial pacific
Waves move energy, not matter
- Energy transfer occurs by circular motions of water molecules, or "orbits" - No net lateral motion of water or seagull as wave passes by
Two ways of describing tidal behavior
- Equilibrium theory - Dynamic theory
If inputs - outputs - balance is negative
- Erosion - Coast gets eaten away
Structures on rocky shores
- Gravel beach - Wave-cut - Sea cave - Tombolo headland - Embayment - Future sea stack - Sea arch - Sea stacks - Wave-cut bench - Pillar
Tidal bulges on Earth result from a combination of
- Gravitational force - Inertia (or centrifugal force)
Three approaches to saving coastal areas
- Hard stabilization --- Structures built to prevent movement of sand along a beach - Beach nourishment - Relocation
Capillary waves coalesce to wind waves given
- High wind velocity - Long wind duration - Long fetch
The greenhouse
- High-energy radiation is transmitted from Sun to Earth - Earth reflects lower energy radiation towards outer space - Lower energy radiation is absorbed by greenhouse gases
The atmosphere - ocean link
- Hot ocean water at the equator evaporates. - Water vapor rises, cools, and falls - Atmospheric convection frictionally induces oceanic circulation
Frequency
- How many wave crests pass a fixed point each second - Measured in cycles per second - So period = 1 / frequency
Period
- How much time passes between each wave crest - Measured in seconds per cycle
Sediment inputs - sediment outputs = balance
- If inputs - outputs - balance is positive - If inputs - outputs - balance is negative - In inputs = outputs - steady state
Dynamic theory of tides
- Includes the effect of continental margins on tides - Predicts that Coriolis forces will move tidal bore in a counterclockwise fashion in northern ocean basins - Rotation occurs about central amphidromic points
Shapes of coastlines controlled by sediment supply
- Inputs - Outgo
The Antarctic circumpolar current
- Is the only current to completely encircle earth - Moves more water than any other current - Has lots of upwelling of nutrients for plankton - Is critical to the THC's global overturning circulation --- Connects the three main ocean basins to the north, thus enabling a truly global circulation --- Permits water masses to undergo large vertical excursions in a stratified ocean without crossing density surfaces
Tsunami at Fukushima Nuclear Plant, Japan
- Known as 2011 Tohoku Earthquake - Magnitude 9.03 earthquake --- Most powerful ever to hit Japan --- Fifth most powerful known - Focal depth of 20 miles - Tsunami reached heights of 133 feet - 15,882 deaths, 6,142 injured, and 2,668 people missing - Three nuclear reactors experienced full melt down - 380,000 buildings collapsed
Exxon Valdez tanker spilled 10.8 million gallons of oil in Prince Willian Sound, Alaska in 1989
- Led to deaths of --- 100,000 and 250,000 seabirds --- 2,800 sea otters --- 300 harbor seals --- 247 bald eagles --- 22 orcas
Oceanic eddies can be generated by anything that perturbs laminar flow
- Local winds channeled by coastal topography - Abrupt changes in wind direction at atmospheric fronts - Oceanic currents at promontories - Water exchange through straits - Instabilities at oceanic current boundaries
Oceanic transgressions are coastal incursions that lead to flooding of landmasses
- Melting of glaciers and ice caps due to global warming - Longshore sediment removal outpaces river inputs - Periods of fast ocean spreading that make shallow seafloor (e.g., Atlantic ocean relative to deep pacific)
Longshore drift
- Migration of sand in direction of wave approach - Beaches as "rivers of sand"
Isostasy
- Mountains and icebergs need deep roots --- Provide buoyant support - As mountains erode or iceberg melts, roots get shallow and boundary shifts upward
Wave motion is oscillatory
- No "net" forward motion of a particle of "parcel" of water - Much like riding on a Ferris wheel
Celerity is related only to water depth (d)
- Not wavelength or period as with deep-water waves - C^2 = g x d, or C = square root of g x d where g is the gravitational acceleration (a constant = 9.8 m/sec^2) and d is depth (in m)
Marine pollution
- Plastic trash pollution on beach of Labuan Bajo (Flores Island) - 5.25 trillion pieces of plastic trash in the world's oceans, and each year, 8 million tons of plastic are added to the count - The deep-water horizon spilled an estimated 210 million gallons of oil in the gulf of Mexico in 2010. - Biomagnification of polychlorinated biphenyls (PCBs) concentrates toxins up the food chain. - New York State discourages children under 15 not to eat > ½ lb of local bluefish or striped bass each week because of PCBs - A 3,000-passenger ship, which today would rank just over medium - size, can produce 21,000 gallons of sewage a day - Mercury is a known neurotoxin that can bioaccumulate in humans causing - Numb or tingling fingers, lips and toes - Developmental delays in children - Muscle and joint pain - Increased risk of heart attack - In the 1950sm an industrial plant in Minimata Bay, Japan discharged methyl mercury directly into the ocean water - Children were born with horrific deformities. 2,265 victims have been officially recognized - Eutrophication - a "green tide" resulting from discharge of nutrients into oceans from agricultural fertilizers that lead to explosive algal blooms - Dead organic matter soaks up oxygen and leads to hypoxia, leading to more fish deaths than any other source
Major control in the moderation of global temperatures
- Poles warmed by equatorial waters - Equator cooled by return of polar waters
Rule of thumb
- Ratio of wavelength to wave height is 7:1 - If L = 70 m, then H = 10 m
Outputs
- Remove of sediment by longshore transport - Removal of sediment by offshore transport
Ocean acidification
- Rising CO2 in the atmosphere leads to the production of carbonic acid and bicarbonate - Rising acidity dissolves calcareous shells of mollusks and corals
Must know both temperature and salinity to compute density of water
- Salinity in measure in psu - Practical salinity units (measured by electrical conductivity) - Essentially the same as parts per thousand (ppt) or per mile
Importance of oceanic gyres
- Salinity is homogenized by oceanic gyres - Nutrients are dispersed by surface circulation
Effects of global warming
- Sea level rise due to glacial melting and water expansion --- 20 inches by 2100? - Agricultural productivity shifts - Changing weather patterns --- More intense hurricanes from higher water temps --- More intense droughts - Crashing of marine ecosystems
Which of the following could explain the oceanic transgression
- Sediment was removed from this area - Sea level has risen
The lighthouse below originally was built on land. Which of the following statements about the picture below is true?
- Shoreline has retreated since the lighthouse was built - Oceanic transgression
The wavelength of tsunami is ~200 km/cycle, and L/20 = 10 km
- Since ocean depth is 4-5 km on average, tsunami are shallow water waves - Travel at 800 km/hr in deep ocean - Wave heights in deep ocean are barely perceptible --- Tsunami peak heights rise to 10 m or more as depth lowers
Examples of waves
- Sound (energy moving through air) - Earthquakes (energy through solid Earth) - Ocean waves (energy moving through liquid)
Melting ice and river inputs dilute salinity
- Summer season - Greenhouse ages
Steep seabed gradients make for plunging waves
- Teahupo'o in French Polynesia is a famous location for big waves - Shallow coral reefs (light blue) fringe the islands --- Corals are surrounded by deep water --- Large depth gradient from sea to beach
Antarctic bottom current
- Temperature : -0.5 degrees Celusis (=31 degrees Fahrenheit) - Salinity: 34.65% - Density: 1.0279 g/cm ^3 - 750 years to reach north Atlantic
Coriolis forces
- The Coriolis forces explain why cyclonic systems in the northern hemisphere rotate in a counter-clockwise sense - Coriolis forces in the northern and southern hemispheres are mirror images - Coriolis forces will occur on any spherical planet that rotates about a fixed axis
Examples of advection
- The chinook winds - warm, dry air that blows from the east flank of the Rockies each spring - The Peru oceanic current, heading northerly along the west coast of Souther America - The flow of the Hudson River from upstate to downstate New York
Why doesn't the moon fly off in outer space
- The orbit of the moon around earth is stable because of the combined actions of gravity and inertia - Inertia + gravity = stable orbit - Inertia of rotating object = centrifugal force
Inputs
- Transport of sediment by currents parallel to shore --- Longshore transport - Transport of sediment by currents perpendicular to the shore --- Onshore transport - River supply
Gulf Stream
- Travels 4.5 miles per hour - Water moves 100 miles per day - Depth: 450 m (1500 ft) - Width: 70 km (43 miles) - Amount of water moved is huge! --- 55 million cubic meters per sec --- 300 times flow of amazon river --- 10^15 calories moved between air and water per second ------- 10^6 times world consumption
Tsunami
- Tsunami are shallow water waves - Tsunami can originate from submarine landslides and meteorite impacts - In the deep ocean, tsunami can travel over 500 miles per hour.
Tidal surges are influenced by positions of moon and sun
- Two springs tides are two neap tides each month - Continental margins experience 1,2, or a mixed number of tides per day
Pycnoclines
- Typically coincide with thermoclines and haloclines - Responsible for ocean stratification - Steepest pycnocline located between warm surface waters and intermediate currents
Fetch
- Uninterrupted distance over which the wind blows without significant change in direction - Largest waves along the Antarctic Circumpolar Current
Tsunami result from
- Volcanic eruptions - Landslides - Meteorite impacts - Earthquakes
How is the walker circulation cell related to the Hadley circulation cell
- Walker circulation currents are perpendicular to Hadley circulation currents
Water is most dense at 4 degrees Celsius
- Water < 4 degrees Celsius is buoyant and rises - Leads to overturning in lakes and oceans - But, salinity can modify behavior
Advection applies to
- Water flow on land or in oceans - Groundwater circulation - Wind
Waves can be periodic over distance and over time
- Wave period measures the amount of time it takes for 2 wave crests to pass a single position - Measured in seconds per cycle
Waves are energy in motion
- Wavelength = distance from crest to crest - Amplitude = distance from still water level to crest (or trough) - Wave height = distance from crest to trough - Celerity = wave velocity (m/sec)
Wind waves travel as "wave trains"
- Wavelengths from 2 cm to 100 m - Gravity not surface tension restores smoothness
Capillary waves are "babies" from which larger waves grow
- Wavelengths less than ~2 cm - Surface tension, not gravity, restores smoothness
Steep slop
- Waves "plunge" - Breakers can form "tubes"
Because atomic or molecular bonds in fluids are much weaker than in solids
- When the top layer of a fluid is pushed, the layer below responds to that push - But the layer below can also respond to other forces
Wind
- Wind patterns affect surface temperatures on the earth - Wind frictionally drives oceanic circulation - Winds are observed on Jupiter and mars
Low - pressure mass
- Winds flow downward around edges toward center due to low pressure - Coriolis forces deflect winds to make counter-clockwise flow - Air collects at center and rises upward - Warm, moist air cools and condenses to rain - Warm moist air cools and makes rain
Coriolis effect
- Winds north from the equator are deflected to the east - Winds from the north pole are deflected to the west
High - pressure mass
- Winds spread outward from margins of air mass - Coriolis forces deflect winds to make clockwise flow - Air deficit at center creates vacuum - Cool, dry air rushes downward and can absorb moisture - Cool dry air descends
Freezing ice removes H2O and increases salinity
- Winter season - Ice ages
El Nino
-mA semi-regular cycle in atmospheric pressure in the western pacific - First described in 1904 by Sir Gilbert Walker - Mathematician in British Colonial Service tasked with predicting famines in south Asia after 1877 catastrophe - Begins with the southern oscillation
Trade winds
0 degrees to 30 degrees Lat and from east to west
Objects launched from the equator have twice the momentum (= mass x velocity) as objects launched from 45 degrees North latitude
0 km/hr
Mid-latitude waters have
1 thermocline but 2 or more haloclines
What is the earth's velocity at the equator in km/hr relative to the north pole
1667 km/hr
How many spring tides occur over one month (approximately)?
2
The tilt of earth's rotational axis relative to the plane of rotation about the Sun is called Earth's obliquity. Which number represents that angular tilt?
23.5 degrees
Earth rotates every
24 hrs about its tilted north-south axis
How long does it take for the Earth-moon system to complete one full rotation
27.3 days
Westerlies
30 degrees to 60 degrees Lat and from west to east
That tilt, or obliquity, is at an angle of
32.5 degrees relative to the plane that Earth orbits the Sun
Today there are 365 days in a year. During the Cambrian (560 Ma), there were 425 days in a year. How many days will make up a year 280 million years in the future?
335 days
The angular velocity (in degrees per hour) is the same over the entire planet
360 degrees divided 24 hr = 15 degrees / hr
For context, the average American home uses
39 billion Joules of electricity each year
At what temperature is water density the highest
4 degrees Celusis
How many ocean-scale gyres do you see?
5
Air mass
A body of air measuring > 1,500 km across with uniform physical characteristics
Estuary
A body of water partially surrounded by land, where freshwater from a river mixes with ocean water
What is the scientific definition of a wave?
A disturbance caused by the movement of energy through some medium (solid, liquid, or gas)
In 1963 the nuclear-powered USS thresher
A fast attack submarine, was lost off the coast of Massachusetts with all hands
Gyre
A flow of current around the periphery of an ocean basin
Lagoon
A long, shallow body of seawater isolated from the ocean - behind these sand dunes
Spilling wave
A more gradually sloping bottom generates a milder, as the crest slides down the face of the wave
Swell
A pack of waves with similar wavelengths and speeds
An inlet
A passage to the ocean - may be cut through a bay mouth bar by tidal action, by water flowing from a river emptying into the bay, or by heavy storm rains
Atmospheric circulation is driven by solar heating
A review of convection
Rip currents
A rip is a strong, localized, and narrow current of water which moves directly away from the shore --- Incorrectly called "rip tides" --- Cut through the lines of breaking waves like a river running out to sea --- Travel up to 8 ft/sec, faster than Olympic swimmer
Tidal wave
A steep wave moving upstream generated by the action of the tide crest in the enclosed area of a river mouth
Slack water
A time of no currents, occurs a short time after high and low tides when the current changes direction
Waves
All of which are disturbances caused by the movement of energy from a source through some medium (solid, liquid, or gas)
Dynamic theory of tides and amphidromic points
Amphidromic tides lead to higher tides in northeastern parts of ocean basins in northern hemisphere
At mid latitudes in the northern hemisphere, cold north-to-south surface currents and upwelling of deep water generally occur
Along the west coasts of continents
Surface currents
About 10% of the water in the world ocean is involved, water flowing horizontally in the uppermost 400 meters (1,300 feet) of the ocean's surface, driven mainly by wind friction
How long are the cycles from one El Nino event to the next
About 3 to 5 years
Dynamic theory
Adds complexities of coastlines, bays, ocean basin geometry, earth deformation, and role of the sun
Why is the Ekman spiral important?
Advection (of wind) can lead to Convection (of ocean water)
Why does water flow around the periphery of the ocean basin instead of spiraling to the center
After all, the Coriolis effect influences any moving mass as long as it moves, so water in a gyre might be expected to curve to the center of the north Atlantic and stop
The net motion of the water down to about 100 meters (330 feet)
After allowance for the summed effects of Ekman spiral (the sum of all the arrows indicating water direction in the effected layers), is known as Ekman transport (or Ekman flow)
What might account for the desert belts at 30 degrees North and South latitude
Air descending at the boundary between the Hadley and Ferrel cells has lost its moisture
Meridional
Aligned with lines of longitude
Newton's first law of inertia
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force
Advection of water by wind displaces
And allows colder and denser water to rise
Cyclonic flows of low
And high pressure air masses
Some of these caves may eventually form sea arches
And in time collapse to become sea stacks as wave energy continues to erode the cliffs
Continents interrupt ocean water flow
And not every coast sees 2 tides a day
Fastest at the equator
And slowest near the poles
The place where ocean meets land is usually called shore
And the term coast refers to the larger zone affected by the process that occur at this boundary
Contiental landmasses modify the pattern of surface winds
And therefore of oceanic circulation currents
Tracers
Another method, developed for studying thermohaline circulation, senses the presence in seawater of chemical, artificial substances with known histories of production of release
Which of these deepwater currents is the most dense
Antarctic bottom current
AABW
Antarctic bottom water
In the northern hemisphere
Anti-cyclones spin clockwise and have dry high-pressure centers
The popular media and general public tend to label
Any unusually large wave a "tidal wave" regardless of its origin
Plunging waves
Form when waves approach a steeply sloping bottom
River-dominated deltas
Are fed by a strong flow of freshwater and continental sediments, and they form in protected marginal seas
Wind waves
Are gravity waves formed by the transfer of wind energy into water.
The prevailing surface winds between the equator and 30 degrees north latitude
Are known as the "trade winds" and move from east to west
Erosional coasts
Are new coasts in which the dominant processes are those that remove coastal material
Low-energy coasts
Are only infrequently attacked by large waves
Tides
Are periodic, short-term changes in the height of the ocean surface at a particular place, caused by a combination of the gravitational force of the moon and sun and the motion of earth
Depositional coasts
Are steady or growing because of their rate of sediment accumulation or the action of living organisms (such as corals)
Marine erosion is usually most rapid on high-energy coasts
Areas frequently battered by large waves
Remember that Coriolis Effects result from changes in momentum
As objects move towards or away from a rotational axis
It seems strange to refer to tsunami - waves with wavelengths up to 200 kilometers (125 miles)
As shallow water waves
Equilibrium theory
Assumes earth is a smooth ball
This deeper layer of water moves
At an angle to the right of the overlying water
Water vapor condenses to rain
At equator to make rainforest belt
Solar heating of oceans creates
Atmospheric convection cells affected by Coriolis forces
So winds along the coast induce a flow
Away from the coast
Inland of the berm crest, extending to the farthest point where beach sand has been deposited
Backshore
Thermohaline circulation
Because density is largely a function of water temperature and salinity, the movement of water due to differences in density (therme, "heat"; halos, "salt")
Which American Founding Father first discovered the Gulf Stream?
Ben Franklin
The peaked top of the highest berm, is usually the highest point on a beach
Berm crest
Westerly winds from Coriolis forces drive systems to the East
But high-pressure cells move more quickly than low-pressure cells
A sandy beach might form the shore in an area
But the coast or coastal zone includes the marshes, sand dunes, and cliffs just inland of the beach, as well as the sand bars and throughs immediately offshore
Wavelength determines the size of the orbits of water molecules within a wave
But water depth determines the shape of the orbits
In an ocean wave, a ribbon of energy is moving forward at the speed of the wave
But water is not
Nor'easter systems travel west to east
But winds at coast originate from NE
Is pushed
By wind
Two - body systems orbit about a center of mass
Called barycenter is located beneath Earth's surface
Earth's tilt
Called its obliquity, gives rise to seasonality
Wind waves grow from
Capillary waves
If water returning to the ocean - the backwash
Carries back the same amount of material as it delivered, the beach slope will be in equilibrium; that is, the beach will not become larger or steeper
Water from waves washing onto a beach-the swash
Carries particles onshore, increases the beach's slope
Solar tides
Caused by the gravitational and inertial interaction of the sun and earth
Which of the following parameters of a wave is measured in meters per second
Celerity
Yes, there really is a hill near the middle of the North Atlantic
Centered in the area of the Sargasso sea; satellite images provide the evidence
In an ocean eddy that is downwelling in the northern hemisphere, will the rotation be clockwise or counter-clockwise?
Clockwise
Suppose instead of a low-pressure cell with upward drafts of air, we have a high-pressure cells with downdrafts. Is the flow clockwise or counter-clockwise?
Clockwise
What is the sense of rotation if your eyeball looked from the south pole
Clockwise
Coriolis effects are weak near the
Coast
The natural sector of a coastline in which sand input and sand outflow are balanced may be thought of as a
Coastal cell
Wind blowing parallel to shore or offshore can cause
Coastal upwelling
Uplifted terraces
Coastline rises above sea due to jerky uplift by subduction events at active margins
Tectonic motions and isostatic adjustment can change the height and shape of a coast
Coasts can experience uplift as lithospheric plates converge or can be weighted down by masses of ice during a period of widespread glaciation. The continents slowly rise when the ice melts.
Upwelling
Cold ring
What causes Earth's tides?
Combination of gravity and inertia
Oceanic circulation at the surface is
Controlled by prevailing wind directions
Other forces
Coriolis forces
Low tides
Correspond to the throughs, the area between bulges
In the 1890s it was reported that Peruvian fishermen were using the expression
Corriente del Nina ("current of the [Christ] child") to describe the flow; that's where the name, El Nino, came from
Minor gyres in fair north rotate
Counter-clockwise
By analogy with atmospheric cyclonic cells, would an upwelling eddy in the Northern Hemisphere rotate clockwise or counterclockwise
Counterclockwise
High and low pressure cells are
Coupled
The reef is not a single object, but a composite of more than 3,000 individual coral reefs
Covering 350,000 square kilometers (135,000 square miles) - collectively the largest structure made by living organisms on earth
Although the main cause of tides is the gravity of the moon and sun acting on the ocean, the forces that actually generate the tides vary inversely with the
Cube of the distance from Earth's center to the center of the tide-generating object (the moon or sun)
After sinking
Current travels south and connects with Antarctic bottom current
Straight wave fronts evolve to
Curved wave fronts
A storm in the Northern Hemisphere of Jupiter
Cyclone with updrafts
A breaking wave
D<L/2
Fjords
Deep, narrow bays, are often formed by tectonic forces and later modified by glaciers eroding valleys into deep, U-shaped throughs.
Winds from the equator to the north pole are
Deflected east
Winds from the north pole to the equator are
Deflected west
The shoreline in such places is much different from its configuration at the end of the last ice age. The most important of these coastal features
Deltas
Path of individual water molecule is circular in deep water
Diameter of orbits gets smaller with increasing depth
Waves can have the same celerity (meters per sec) but
Different periods (and frequencies)
Ekman transport leads to a
Doming of water in the center of the North Atlantic Gyre
Downwelling
Downward movement
Suppose that a wind from south to north blows along a coast to the east in the northern hemisphere. Will Ekman transport lead to
Downwelling
The Labrador Current off the east coast of Labrador, Canada
Downwelling
Anticyclones
Dry
The water itself may occupy more or less volume as its temperature varies
During times of global warming, seawater expands and occupies more volume, raising sea level
Salt wedge estuaries
Form where a rapidly flowing large river enters the ocean in an area where tidal range is low or moderate
What heat source drives mantle convection
Earth's magnetic field
So Coriolis forces deflect the tide wave towards the ____ in the northern Atlantic
East
West boundary currents in Northern Hemisphere gyres are different from
East boundary currents
Which pattern would you expect for Northern Hemisphere Gyres?
East boundary currents: fast, deep, narrow
The result is a dome shifted to the
East called the Sargasso Sea
Cold-core eddies form in the gulf stream as it meanders
Eastward upon leaving the coast of North America off Cape Hatteras
Water rushing out because of the fall in sea level as tide approaches
Ebb current (the terms ebb tide and flood tide have no technical meaning)
Reverse flow
El Nino
Disturbing force
Energy that causes ocean waves to form
By a depth (d) of ½ the wavelength (L)
Energy transfer (and orbital wave motion) are negligible
Tides are a
Form of wave
All major and minor oceanic gyres in the northern hemisphere rotate clockwise
False
Inertia (or centrifugal force)
Far side from moon
East currents
Fast and deep
West currents
Fast and deep
Dynamic theory of tides
First proposed in 1755 by Laplace, added a fundamental understanding of the problems of fluid motion to Newton's breakthrough in celestial mechanics
Water rushing into an enclosed area because of the rise in sea level as a tide crest approaches
Flood current
Global warming consequences
Flooding of coastal regions by melting of continental ice sheets
Gyre (gyros, "a circle")
Flow, around the periphery of an ocean basin
The west wind drift, or Antarctic circumpolar current, as this exception is called
Flows endlessly eastward around Antartica, driven by powerful, nearly ceaseless westerly winds
Glacial fjords
Glacially carved valley flooded by sea level rise with characteristic U cross-section
Rainforests and deserts reflect
Global atmospheric convection cells
Climate scientists are worried that global warming may terminate thermohaline circulation
Global warming will cause Greenland ice to melt, diluting the thermohaline current
What two forces work together to create an Ekman Spiral and begin the motion of the surface currents
Global winds and Coriolis forces
Which equation describes the relationship for gravity tidal forcing for the Earth and Moon?
Gravitational force for tides = mass of moon / (distance) ^3
Which disturbing force is most responsible for Earth's tides?
Gravity
The coldness at the poles results from
Greater absorption at the poles by thicker slices of atmosphere than at the equator and more concentrated footprint of light beams on the equator than at the poles
Density of H2) increases with lower temperatures until reaching a maximum at 4 degrees Celusis
H bonds hold molecules further apart in solid than in liquid
Thermo
Heat
Costal dunes
Heavy sand and supply and high winds
If a wave gets any higher than this ration for its wavelength, it will break, and excess energy from the wind will be dissipated as turbulence
Hence the whitecaps or cumbers associated with a fully developed sea
Downdrafts
High pressure zones
As a rule of thumb, are high pressure systems associated with rainy or fair weather
High pressure: fair. Low pressure: rainy
A second factor is the length of time the wind duration
High winds that blow only a short time will not generate large waves
The shape of a gyre in the absence of Coriolis Effects
Highly Symmetric
But Coriolis effects make gyres
Highly asymmetric
Forced waves
Huge shallow - water waves are never free of the forces that cause
Equilibrium theory
In his pioneering work that described the motion of planets, moons, and all other bodies in gravitational fields, Issaac Newton developed a gravitational mode of the tides
Smaller gyres at poles and
In north Indian ocean
Does the ACC flow
In the direction of Earth's rotation
Ocean wave orbitals dimmish with
Increasing depth
The wind-driven horizontal movement of water can sometimes
Induce vertical moment in surface water (wind-induced vertical circulation)
Analogy with skaters again
Inertia (centrifugal force) leads to oceanic bulge opposite Moon and Sun
Breakwater
Interrupts the progress of waves to the beach, weakening the longshore current and allowing sand to accumulate there
Onrushing water disappears
Into a beach made of coarse particles, so little water is left to rush down the slope, thereby minimizing the transport of sediments back to the ocean
Wave crest
Is the highest part of the wave above average water level
The gulf stream
Is the largest of the western boundary currents
A fully developed sea
Is the maximum wave size theoretically possible for a wind of a specific strength, duration, and fetch
The surf zone
Is the region between the breaking waves and the shore
Wave through
Is the valley between wave crests below average water level
The card beneath
It in the deck feels this card's movement and begins to move
The amount of water in the world ocean can vary. Sea level is lower during periods of global glaciation (ice ages) because some of the water that was previously in the ocean becomes frozen in land-based glaciers
It is higher during warm periods, when water from melting glaciers is released back into the ocean. Periods of abundant volcanic outgassing can also add water to the ocean and raise sea level
Remember, the second card in the deck cannot feel the wind directly
It is only moving in response to the movement of the topmost card
Are the waves in the southern ocean likely to be highest in January or July
July
Smooth, nearly level wave - cut platforms can be found
Just offshore, which marks the submerged limit of rapid marine erosion
What is the equation for wavelength (L) in terms of period and celerity
L = C x P
Wave bottom slows when depth
L/2
With increasing salinity, the density of water increases
Linearly
Weather reflects
Local (geographically smaller) atmospheric convection cells
Local changes are bound to occur, and two other factors produce variations in
Local sea level
Sediments are also transported in the surf zone in a
Long shore current
Tsunami
Long-wavelengths, shallow-water progressive waves caused by the rapid displacement of ocean water; a descriptive Japanese term combining tsu ("harbor") with nami ("wave")
The movement of sediment (usually sand) along the coast, driven by wave action
Longshore drift
Below the low-tide mark, wave action turbulent backwash, and longshore currents excavate, parallel to shore
Longshore through
Would you expect high pressure or low pressure zones at the boundary between the polar and Ferrel cells
Low pressure
Rising air creates
Low pressure at the surface
Updrafts
Low pressure zones
In the north hemisphere
Low-pressure cyclones with rising air rotate counter-clockwise
Storms rotating counter-clockwise in the Northern Hemisphere are
Low-pressure cyclones with updrafts
Think of the figure-skaters' joined hands as gravity (if they lost their grip, they'd start sliding apart as a result of inertia, or the centrifugal force)
M is called the Center of Mass of this rotating system
Plate tectonics is driven by
Mantle convection
This results in a stair - step formation along the coast known as a wave-cut terrace
Marine terrace
Gravitational force for tides is proportional to
Mass of planet / (distance)^3
Momentum is
Mass x velocity and is maximized at the equator
On coasts with mixed tides, the zero tide level is the average level of the lower of the two daily low tides
Mean lower low water or MLLW
Thermohaline circulation
Movement of ocean water caused by density differences due to temperature and salinity
Importance of oceanic gyres
Movement of water from equator to poles transfers heat energy from equator to poles
Lowest tides occur when moon and sun are at 90 degrees
Neap tides
When earth + moon alignment is perpendicular to earth + sun alignment - smallest tides
Neap tides
Gravitational force
Near side to moon
Is the Coriolis effect more pronounced for objects near the equator or near the poles
Near the poles
Is the change in velocity higher near the equator or near the poles?
Near the poles
Waves slow down
Near the shore
Do you see a lot of change in salinity as the seasons pass based on the bottom scroll?
No
If inputs = outputs - steady-state
No change in coast position
Is the ice in icebergs salty
No! The formation of ice takes H2O out of seawater and leaves NaCl behind, making the water saltier and denser
NADW
North Atlantic deep water
These channels allow the cold, dense water formed in the Arctic to flow into North Atlantic to form
North Atlantic deep water
Cold waters upwell off the coast of California due to Ekman transport. What must the prevailing wind direction be here?
North to South
The Antarctic circumpolar current
Not considered a gyre because the circulation encompasses a continent
Because of the urging of the Coriolis effect
Note that east-west currents in the North Atlantic gyre flow to the right of the drinking winds
Between 20 million and 50 million cubic meters
Of this brine from every second
The pacific coast of the United States has a mixed tidal pattern
Often a higher high tide, followed by a lower low tide, a lower high tide, and a higher low tide each lunar day
The earth-moon system revolves
Once a month - (27.3 days) around the system's center of mass
Diurnal
Once/day
Others have diurnal (daily) tides
One high and one low
Interference
One wave doesn't crawl over the others when they meet; instead, they add to or subtract from one another
Deep water waves are defined as waves traveling over depths that are what multiple of the wavelength (L)?
One-half the wavelength (2L)
Doming is visible in NASA satellite images
Only 2 meters higher than surrounding ocean
The planets lie in nearly the same
Orbital plane, or ecliptic
In the US, low-pressure cyclonic cells often originate
Originate from warm moist air originating in the Gulf of Mexico
Wind and currents, storm surges, an El Nino or La Nina event
Other effects of water in motion can force water against the shore or draw it away
Sun, moon, and earth
Parallel alignment twice per month --- Spring tides Perpendicular alignment twice per month --- Neap tides
Coastal plains and sandbars
Passive continental margins
Waves also are classified in terms of their
Period
Waves are defined in terms of their
Period
Paradoxically, net water flow over the water column may be
Perpendicular to the wind direction
Coriolis effects are strong near the
Poles
Tsunami arrive at ~ 50 km/hr as wall of water 10 m high
Preceded by sharp pullback of water
The process of wave separation, or dispersion
Produces the familiar smooth undulation of the ocean surface called swell
Wave trains
Progressing groups of swell with the same origin and wavelength
Because the wave form moves forward, these waves are a type of
Progressive wave
The balance of wind energy, friction, the Coriolis effect, and the pressure gradient
Propels gyres and holds them along the edges of ocean basins
When a truck passes you at high speech, after it passes, the pressure difference
Pulls you towards it
Cyclones
Rainy
The bending of waves as they shoal (approach shallow water) is called
Refraction
Both the rate of rotation and the degree of tilt are
Remnants from the collision with the Mars-sized object that made the moon
Global heating
Rising CO2 in the atmosphere leads to the capture of infrared radiation, leading increased temperatures
River dominated
River builds out into ocean from coastline
This is an aerial photograph of the Yellow River delta in China
River dominated
Swampy deltas
Rivers deliver high sediment loads
Is salty water more or less dense than freshwater
Salt water is more dense and will sink in fresh water
Haline
Saltiness
The parade of wave cuts
Sea caves into the cliffs at local zones of weakness in rocks
How does the formation of sea-ice in the winter influence seawater density
Sea-ice formation increases seawater density
Foreshore
Seaward of the berm crest, is the active zone of the beach, washed by waves during the daily rise and fall of the tides
Shapes of coastlines controlled by sediment supply
Sediment inputs - sediment outputs = balance
If the wavelength of a tsunami is in the range of 200 km/cycle, and the ocean depth on average is 4 km, then tsunami must always be
Shallow-water waves
Which scientist first proposed an atmospheric convection cell within the Pacific Equatorial Plane
Sir Gilbert Walker
Sea cliffs
Slope abruptly from land into ocean, their steepness usually resulting from the collapse of undercut notches
East currents
Slow and diffuse
West currents
Slow and diffuse
So, do waves speed up or slow down as they reach shallower water depths
Slow down
Wave refraction
Slowing a bending of waves in shallow water
Over time, do offshore currents smooth or roughen rocky shorelines
Smooth
The turbulent mass of agitated water rushing shoreward during and after the break is known as
Surf
Constructive and destructive interferences
Surf beat
Atmospheric convection cells generate
Surface winds from high to low pressure
The best course of action to take when you are caught swimming in a rip is to
Swim parallel to the shore
Why does the Gulf Stream sink in the Labrador Sea
The Gulf Stream gets saltier and colder as it travels to the northern Atlantic Ocean
Storm surge
The abrupt bulge of water driven ashore by a tropical cyclone (hurricane) or frontal storm
An archer stands at the north pole and aims his arrow directly at a target on the equator. What effect will the earth's rotation have on the path of the arrow after it is shot?
The arrow will travel to the west of the target.
Suppose we spray the bottom of a glass of water with liquid nitrogen (temperature = - 196 degrees Celsius) and create the temperature profile indicated. What would happen to the water at the base of the glass?
The bottom-most layer will rise
Front
The boundary between air masses
High tides
The bulges are the crests of the planet - sized waves
Destructive interference
The cancelation effect of subtraction, not because of harm to lives or property but because wave interference destroys or cancels waves
CE
The center of earth - are the inward pull of gravity and the outward - moving tendency of inertia exactly equal and opposite
Southern oscillation
The change in atmospheric pressure (and this in wind direction)
Restoring force
The dominant force that returns the water surface to flatness after a wave has formed in it
A modification proposed by Pierre - Simon Laplace about a century later
The dynamic theory, takes into account the speed of the long-wavelength tide wave in relatively shallow water, the presence of interfering continents, and the circular movement of rhythmic back-and-forth rocking of water in ocean basins
If the rotational axis of the earth were not tilted relative to its orbital plane around the sun, then
The earth would not experience seasons
In the northern hemisphere, winds from te equator to the north are deflected to
The east
Westward intensification
The effect on currents flow
Coupling between wind and solids is pretty straightforward
The entire solid moves in the direction of the wind
The poles are coldest
The equator is hottest
Ocean waves are classified by disturbing force that creates them
The extent to which the disturbing force continues to influence the waves once they are formed, the restoring force that tries to flatten them, and their wavelength
Which statement concerning the movement of water in waves on the open ocean is correct?
Water molecules follow a circular path as the wave passes
Spring tides
The large tides caused by the linear alignment of the sun, earth, and moon "to move quickly springen
Eddies
The looping meanders sometimes connect to form turbulent rings, that trap cold or warm water in their centers and then separate from the main flow
What is the definition of laminar flow
The molecules within the fluid flow in straight lines
Active coasts near the leading edge of moving continental plates, were found to be fundamentally different from
The more passive coasts near trailing edges
Antarctic bottom water
The most distinctive of the deep-water masses, is characterized by a salinity of 34.65%, a temperature of 0.5 degrees Celius (31 degrees Fahrenheit), and a density of 1.0279 grams per cubic centimeter
Argo system
The most successful, a vast sampling net-work of nearly 4,000 independently drifting sensors
Amphidromic point
The node (or nodes) near the center of an ocean basin (amphi, "around"; dromas, "running")
Wave frequency
The number of waves passing a fixed point per second
Deflections due to the Coriolis effect in the northern hemisphere are
The opposite of those in the southern hemisphere
Tractive forces
The outward - flinging force of inertia and the inward-pulling force of gravity
Ekman spiral
The resulting situation after the Swedish oceanographer who worked out of the mathematics involved
Deep water follows
The same trends
Distributaries
The split ends of the river - in a characteristic bird's foot shape
Which is the best definition of inertia
The tendency for a moving object to keep moving (or for a resting object to stay at rest)
Wave period
The time it takes for a wave to move a distance of one wavelength
Advection
The transfer of heat or matter horizontally by fluid flow
Sverdrup (SV)
The unit used to express Volume transport in ocean currents, named in honor of Harald Sverdrup, one of the last century's pioneering oceanographers.
When higher sea level returned
The valleys were flooded, or drowned, with seawater
Wave height
The vertical distance between a wave crest and the adjacent through
The term spiral is somewhat misleading
The water itself does not spiral downward in a whirlpool-like motion like water going down a drain
To turn further right
The water would have to move uphill against the pressure gradient (and in defiance of gravity), but to turn left in response to the pressure gradient would defy the Coriolis effect
Water is moving faster than
The wave
On coasts with diurnal and semidiurnal tides
The zero tide level is the average level of all low tides (mean low water, MLW)
Vertical circulation
Thermohaline conveyer belt
King tides
These very high tides are sometimes
After they are formed, wind waves and tsunami are free waves
They are no longer being acted upon the force that created them and do not require a maintaining force to keep them in motion
Shallow-water waves
This behavior of tides is only one variation from the ideal that the dynamic theory explains
Because earth's mass is 81 times that of the moon
This common center of mass is located not in space but 1,650 kilometers (1,023 miles) inside earth
The volume of the ocean's "container" may vary, high rates of seafloor spreading are associated with the expansion in volume of the oceanic ridges
This expansion displaces the ocean's water, which climbs higher on the edges of the continents. Sediments shed by the continents during periods of rapid erosion can also decrease the volume of ocean basins and raise sea level
The restoring force for very small capillary waves
Those with wavelengths less than 1.73 centimeters (0.68 inch) - is cohesion, where as for larger waves, gravity pulls the crests downward
Running at high speed
Thresher may have encountered an internal wave and been forced beyond its test depth
The moon and sun create
Tidal bulge on Earth through differences in gravitational attraction on close and far sides of Earth
The rise or fall in sea level as a tide crest approaches and passes will cause a
Tidal current of water to flow into or out of bays and harbors
The reference level to which tidal height is compared is called the
Tidal datum
Tide-dominated
Tidal flow landward and seaward causes channels and islands perpendicular to coast
Weaker effect for Sun results from farther distance from the Earth
Tidal forcing varies as cube of distance
Lunar tide
Tides caused by gravitational and inertial interaction of the moon and Earth, complete their cycle in a tidal day (also called a lunar day)
Astronomical tides
Tides caused by inertia and the gravitational force of the sun and moon
Surface water
To a depth of about 200 meters (660 feet)
Intermediate water
To about 1,500 meters (5,000 feet)
The key to understanding the equilibrium theory of tides is
To see Earth turning beneath these bulges
Central water
To the bottom of the main thermocline (which varies with latitude)
Will the Coriolis effect deflect a rocket launched north from the equator to the east or the west
To the east
Southern hemisphere currents flow
To the left
Because of the Coriolis effect Northern hemisphere surface currents flow
To the right of the wind direction
If the island is close to shore, a bridge of sediments may accumulate to connect the island to the mainland
Tombolo
The maps above depict the development of the western interior seaway in the united states during the cretaceous period, splitting the US mainland in two. Does the period from 105 Ma to 85 Ma represent a time of oceanic
Transgression
The transfer of energy from water particle to water particle in these circular paths, or orbits
Transmits wave energy across the ocean surface and causes the wave form to move
Mangroves
Trees that can grow in salt water
The momentum of objects at Earth's equator is greater than the momentum of objects located close to the Earth's poles.
True
Seismic sea waves
Tsunami caused by the sudden, vertical movement of earth along faults (the same forces that cause earthquakes
Semidiurnal
Twice/day
Some coastlines experience semidiurnal (twice daily) tides
Two high tides and two low tides of nearly equal level each lunar day
The gull moves in circles
Up and forward as the tops of the waves move to its position, down and backward as the tops move past
Tidal reach measures the vertical distance between low and high tide
Up to 16m at Bay of Fundy
The shape of a coast is a product of many processes
Uplift and subsidence, the wearing down of land by erosion, and the redistribution of material by sediment transport and deposition
Upwelling
Upward movement of water, the process brings deep, cold, usually nutrient-laden water toward the surface
The Canary Current along the west coast of Africa.
Upwelling
The Gulf Stream along the East Coast of the US.
Upwelling
The distance velocity (in km or miles per hour)
Varies with location
Dissolved sodium chloride (NaCl) also changes water density. Where did the chlorine in seawater come from?
Volcanic emissions
Downwelling
Warm ring
El nino
Warm water to the east
La nina
Warm water to the west
Deep water
Water below intermediate water but not contact with the bottom, to a depth of about 4,000 meters (13,100 feet)
Bottom water
Water in contact with the seafloor
Shallow-water waves
Waves in water shallower than 1/20th their original wavelength
Deep-water waves
Waves moving through water deeper than half their wavelength
Wave-dominated
Waves push sediment back onto coastline
Tidal forcing by Sun is 46% as strong as tidal forcing by Moon
Weaker but not insignificant
Classic inverted "V" forms
When cold front from west swoops in on cyclonic warm front to east
Dynamic theory of tides and amphidromic points
When the moon is north of the equator, it pulls the bulge of ocean water to the north
Distinct from convection
Which involved the vertical transfer of heat and/or matter
Mean seal level
Which is the height of the ocean surface averaged over a few years' time
This is due to wave refraction
Which results in wave energy being focused onto headlands and away from bays
Lateral movement of air from high pressure to low pressure is called
Wind
Why does wind blowing across the surface of water lead to upwelling?
Wind advects surface water, and water upwells to maintain isostatic balance
Wind strength
Wind must be moving faster than the wave crests for energy transfer to continue
Tsunami (not Tsunamis) are not
Wind waves or tide waves
Surface currents
Wind-driven movements of water at or near the ocean's surface
Upwelling occurs when
Winds blow along the west coast of a continent in the northern hemisphere
Wind duration
Winds that blow for a short time will not generate large waves
Wave heights are highest at the acc
Winds travel without obstruction by continents
Rogue wave
Would be much larger than any notice before or after, and it would be higher than the theoretical maximum wave capable of being sustained in a fully developed sea
Pycnocline
Zone of major density change
Halocline
Zone of major salinity change
Thermocline
Zone of major temperature change
Coriolis forces result from
differences in momentum between the equator and the poles
Gravity and inertia lead to
oceanic bulges on the sides nearest and farthest from the moon
Three of these factors are responsible for eustatic change
or variations in sea level that can be measured all over the world ocean, whereas the other two influence local sea level
Deeper estuaries exposed to similar tidal conditions but greater river flow become
partially mixed estuaries
There are five large western boundary currents; the gulf stream (in the North Atlantic), the Japan or Kuroshio Current (in the North Pacific)
the Brazil current (in the South Atlantic), the Agulhas Current (in the Indian Ocean), and the east Australian Current (in the south pacific)
Is the additive formation of large crests or deep throughs, the size of
throughs, the size of which exceeds the size of each participating wave
The third factor is the uninterrupted distance over
which the wind blows without significant change in direction, the fetch