Chapter 6 Air-Water Interaction, 7 Ocean Circulation, 8 Waves, 9 Tides and 10 Coastal Waters

What is an isothermal layer?

A layer of constant temperature

Tilt configuration that cooresponds to spring

A the vernal equinox, which occurs on or about March 21st, the sun is directly overhead along the equator. During this time, all places in the world experience equal legths of night and day. In the Northern hemisphere, the vernal hemisphere is also known as the vernal equinox.

semidiurnal tidal pattern

A tidal pattern exhibiting two high tides and two low tides per tidal day with small inequalities between successive highs and successive lows; a semi-daily tide.

What is Ekman transport?

All water layers combined to give net movement 90 degrees from wind direction

What is the influence of swash and backwash on wave refraction and longshore drift?

As a result of wave refraction, swash moves up the beach face at a slight angle, but backwash flows down the beach face under gravity and does so perpendicular to beach face. This produces not a back and forth movement of water perpendicular to the shoreline, but a zigzag pattern that moves both water and sediment with a net movement parallel to the shore.

Tilt configuration that corresponds to fall

At the Autumn equinox, which occurs on or about September 23rd, the sun is directly overhead along the equater again. In the Northern hemisphere, the autumn equinox is also known as the fall equinox.

Tilt configuration that corresponds to summer

At the summer soltice, which occurs on or about June 21st, the sun reaches its most northernly point in the sky, directly overhead along the Tropic of Cancer, at 23.5 North Latitude.

What is the influence of backwash on with of berm?

Backwash dominates during strong activity associated with winter and its stormy weather. As a result, sediment is moved off shore and a narrower berm is formed. The eroded sand is transported just beyond where waves break to form off shore sandbars.

prevailing westerlies

Because of the Coriolis Effect, the prevailing westerlies blow from the Southwest to Northeast in the Northern Hemisphere and from Northwest to Southeast in the Southern Hemisphere.

Global or eustatic sea level change is driven by

Changes in glacier ice volumn Changes in seafloor spreading rates Thermal expansion of water

What direction do gyres rotate in the northern hemisphere?

Clockwise

Which way do cyclones rotate in the southern hemisphere?

Clockwise circulation because winds are deflected towards the left

constructive wave interference

Constructive or destructive interference results when two swells of the same wavelength come together. If the wave trains are in phase, meaning the crest of one meets the crest of another, we get constructive interference, and wave heights are the sum of both waves. If wave trains are out of phase, with the crest of one wave meets the trough of the other, we get destructive interference. This reduces wave heights ore eliminates waves altogether.

What is the relationship between divergence and convergence?

Convergence generally means coming together, while divergence generally means moving apart. In the world of finance and trading, convergence and divergence are terms used to describe the directional relationship of two trends, prices, or indicators.

Characteristics of air masses at high pressure

Cool, sinking air creates high pressure at the surface.

Which way do anticyclones rotate in the northern hemisphere?

Coriolis Effects sets up the wind to be deflected to the right and it moves clockwise.

Which way do anticyclones rotate in the southern hemisphere?

Counter clockwise as winds are deflected towards the left

What direction do gyres rotate in the southern hemisphere?

Counterclockwise

What effet does declination of the moon have on the tidal range?

Declination produces unequal tidal ranges between successive tides.

How do water masses form?

Deep water masses are formed where the air temperatures are cold and where salinity of surface waters are high. The combination of salinity and cold temperatures make the water denser and causes it to sink to the bottom.

Depositional (sandy) shoreline features

Depositional shoreine features are primarily deposits of sand transported by longshore drifts and modified by other processes. A wide variety of landforms are found along depositional coasts, such as extensive coastal wetlands and mudflats. Examples of coastal depositional landforms are spits and bay barriers.

What is the Coriolis Effect's relationship to major wind belts?

Earth is spinning as air moves over its surface. This causes the Coriolis effect. ... Without the Coriolis effect, the global winds would blow north to south or south to north. But the Coriolis effect makes them blow northeast to southwest in the Southern hemisphere or the reverse in the Northern Hemisphere.

ENSO

El Niño-Southern Oscillation

What are the Characteristics of western boundary currents?

Fast, narrow and deep, warm water

Characteristics of air masses at low pressure

Heating creating rising air and low pressure at the surface. Heat rises.

Describe the sea surface temperature, pattern and characteristics of El' Nino

High pressure in East weakens, weak trade winds--> Western warm water flows back East

Isothermal Isohaline versus a stratified water column and how that impacts vertical movements

I don't know...

What is isopycnal? Isothermal? Isohaline?

If the water column has the same density over depth, it has neutral stability. If the water column has the same temperature over depth. If the salinity is constant over depth.

What is the differernce in partical motion between longitudinal and transverse waves?

In a longitudinal wave, the particle motion is parrallel to the direction of wave propagation. In a transverse wave, partical motion is perpendicular to the direction of wave propagation.

Climate effects in South America due to

In extreme years, western South America experiences intense rain and the western pacific experiences drought.

What happens to a wave's speed, wavelength, height and steepness as it approaches shore?

It slows the wave down wavelegth decreases wave heights increase

What is a subtropical gyre?

Large loops of ocean currents bounded by continents Two in the Atlantic and Pacific One in the Indian Ocean

thermocline circulation-where do deep water masses form?

Large volumes of deep water form in the Norwegian sea, then flow in the subsurface to the North Atlantic and become part of the North Atlantic deep water. North Atlantic deep water also originates from the Irminger seas off Greenland and the Labrador Sea. Deepwater forms along the margins of Antarctica. This water mass is known as arctic bottom water and is the densest of all the water masses.

Why does the amount of radiation change with latitude?

Less radiation reaches Earth's surface at high latitudes compared to low latitudes because the Earth's atmosphere absorbs some of it. High angle of incidence equals low latitudes equals more radiation Low angle of incidence equals high latitudes equals less radiation

mixed wave interference

Mixed interference occurs when swells of different wave heights and wave lengths come together. Mixed interference produces waves of different heights. They vary in wave train (surf beat)

What do the lines on the temperature-salinity diagram represent?

Once surface water sinks, it changes little as the processes that change temperature and salinity operate at the surface. Therefore, deep water masses can be distinguised by their temperature, salinity and density characteristics.

Differences between positive and negative feedbacks

Positive feedbacks amplify or reinforce the initial change. Negative feedbacks diminish or counteract the initial change, helping to keep systems stable Positive feedback accelerates a temperature rise, whereas negative feedback slows it down. Scientists have identified several positive feedback loops in the climate system. Ocean warming provides a good example of a potential positive feedback mechanism.

polar easterlies

Prevailing winds that blow from northeast in the Northern hemisphere and from Southeast in the Southern hemisphere.

Difference between relative and eustatic sea level changes

Relative sea level change are local causes. Global or eustatic sea level change is change in volumn of sea water.

What are the characteristics of eastern boundary currents?

Slow, wide, shallow and cold water

What is the Ekman spiral speed and direction?

Speed and direction of flow varies with depth

What are spring tides?

Spring tides is when the Earth, sun and moon are aligned or when tidal range is at its maximum.

Pattersn in SST and Thermocline during El Nino?

Strong El Nino = ENSO warm phase High pressure in the East weakens, reducing the pressure difference between the west and east and weakening the trade winds. In very strong El Nino events, walker may actually reverse with the trade winds blowing from west to east. With weak or reverse trade winds, warm water from the Western Pacific flows back east. This deepens thermocline in the east and instead of cold, nutrient rich water, upwelling supplies warm nutrient poor water.

What is the patterns in SST and Thermocline during La Nina?

Strong La Nina = ENSO cool phase Some years, what we call normal conditions are enhanced. That is there are stronger pressure differences and stronger trade winds. As a result, cooler water penetrates farther west in the south equatorial pacific. The thermocline is also shallower off the coast of South America, producing more upwelling.

What are the causes of tsunami waves?

Sudden change in seafloor, displacement transmitted through water column to surface Most are caused by vertical movement along a fault Largest tsunamis are produced by landslides or under water volcanic eruptions

What is the difference between swash and backwash?

Swash transports sediment landward, backwash transports sediment seaward

Local processes leading to relative sea level change

Tectonicly active margins --> uplift of land. down dropped basins Isostatic adjustments due to removal of ice or sediment--> isotatic uplift Subsidence: compaction and sinking of sediment

How to read temperature-salinity- density diagram

Temperature is plotted on the Y axis Salinity on the X axis The blue lines stretching across the graph are lines of equal density. We see that low temperatures combined with high salinity produce the highest denisities in the bottom right corner. As you move toward the top left, densities decrease.

Which way do cyclones rotate in the northern hemisphere?

The Coriolis Effect causes wind to be deflected right and sets up counter clockwise circulation

Northwest trade winds

The masses of air that move across Earth's surface from the subtropical high pressure belts toward the equatorial low pressure belts constitute the trade winds.

Why does tidal range vary over the monthly tidal cycle?

The moon follows an eliptical path around the Earth. The distance between them varies by about 31,000 miles over the course of the month.

How does the declination of the moon impact the alignment of the tidal bulges?

The moon is not alwasy aligned with the equator, and therefore, the lunar bulge is not always centered over the equator

Describe partical motion in an ocean wave

The movement of particles in ocean waves involves components of both longitudal and transverse waves. Particles move in circular orbits.

What is apogee?

The point in orbit when the moon is farthest from Earth.

What is perigee?

The point in orbit which the moon is closest to Earth

What is perihelion?

The point in the orbit when Earth (planet, asteroid, or comet} at which it is closest to the sun.

What is the purpose of a groin?

The purpose of a groin is to stop the loss of sand to longshore drift. It increases erosion immediately downdrift of the groin. This leads to construction of more groins until you have a groin field.

What is the direction of flow for flood and ebb tide?

The term flood tide describes an advancing high tide. The reverse condition is a receding high tide, referred to as ebb tide.

What is net transport direction?

The term long term current refers specifically to the net movement of water parallel to shore, while long shore drift describes the movement of sediment parallel to shore.

What is the cause of the tides?

The tides are created by the tidal bulges, a distortion of the ocean's surface, because we have two tidal bulges on each side of the Earth, the wavelength and distance between crest to crest is half the circumference of the Earth, and so tides behave as shallow-water waves

What is the cause of the seaons?

The tilt of the Earth's axis - The surface connecting all points in Earth's orbit is called the plane of the ecliptic. Earth's axis of rotationis not perpendicular relative to the plan of the eliptic. Rather, it tilts at an angle of 23.5 degrees. As a result, different hemipheres on Eart are titled more directly toward or away from the sun during Earth's yearly orbit, which is the cause of the seasons.

Tilt configuration that corresponds to winter

The winter solstice, which occurs on our about December 22nd, the sun is directly overhead along the tropic of Capricorn at 23.5 degrees latitude. In the southern hemisphere the seasons are reversed. Thus, the winter solstice is a time when the southern hemisphere is most directly facing the sun, which is the beginning of the southern hemisphere summer.

Describe a thermocline of El Nino

Thermocline deepens in East---> upwelling supplies warm nutrient poor water or there is downwelling Thermocline deeper, water temperature warmer, more storms, flooding.... Lower biological productivity, less food fish.... (El Niño)

What are the causes of divergence and convergence?

Upwelling caused by divergence of water masses at surface with no deep water moving up to replace

What is the difference between upwellng and downwelling?

Upwelling is movement of cold, deep nutrient rich water to the surface. Associated with high productivity Downwelling movement of surface water to deeper parts of the ocean. Associated with low productivity in surface waters

Deep water waves

Water depth is greater than wave base No interferance with ocean bottom Includes all wind generated, open ocean waves

shallow water waves

Water depth is less than 1/20 of the wavelength Ocean bottom interferes with orbits creating an eliptical motion that approaches horizontal oscilation near seafloor Ex: Nearshore wind waves/tsunami tides

Erosional (rocky) Features

Wave action at base of headland leads to wave cut cliffs Sea caves may form at cliff bases Caves may eventually erode to form sea arches Sea stacks are formed when the tops of sea arches collapse under continued erosion

What is the definition of wave refraction?

When a wave approaches shore at an angle, the part of the wave that reaches shallow water first slows down causing the wave to bend or refract.

What is a neap tide and when does it occur?

When the moon is in first or third quarter phase, the solar and lunar tide generating forces are at right angles to eachother. Tidal range is at its minimum

What is wave interference?

When two waves meet, their amplitudes combine

What is the influence of swash on with of berm?

When wave activity is low, as is typically in summer, swash dominates. Sediment is transported on shore, which builds a wider beam. This occurs because water soaks into the beach face and there is less water available to carry sediment off shore on the return flow.

How to determine direction of longshore drift based on depositional patterns

You can determine the dirction of longshore drift by the pattern of sand deposition and erosion relative to the groins.

temperature-salinity (T-S) diagram

a diagram with axes representing water temperature and salinity, whereby the density of the water can be determined

Halocline

a layer of water in which the salinity changes rapidly with changes in depth The marked change in salinity with depth is called the _____.

Thermocline

a steep temperature gradient in a body of water such as a lake, marked by a layer above and below which the water is at different temperatures.

What is the Ekman spiral?

a structure of currents or winds near a horizontal boundary in which the flow direction rotates as one moves away from the boundary

diurnal tidal pattern

a tidal pattern exhibiting one high tide and one low tide during a tidal day; a daily tide

southeast trade winds

blow from the southeast toward the northwest

tidal patterns

diurnal, semidiurnal, mixed Be able to identify three tidal patterns from a chart

temperature and density

generally, the higher the temperature of a substance, the farther apart the particles of the substance and thus the lower the density Temperature increases, density decreases

Air always moves from _____ pressure to ___ pressure.

high low

What is a gyre?

large system of circulating ocean currents

El Niño and La Niña (Southern Oscillation (ENSO))

large-scale weather phenomenon occurs every few years when prevailing winds in the tropical Pacific Ocean weaken and change direction o Above-average warming of Pacific waters affects populations of marine species by changing the distribution of plant nutrients, hurting fishing industry o Low nutrients, low dissolved oxygen (in South America, but in Australia during La Niña) o Severe flooding, storms, drought, mudslides, $ damage, human health hazards (dehydration, diarrhea, zoonotic diseases [lyme, Hanta])

What is aphelion?

the point in the orbit when Earth (planet, asteroid, or comet) is furthest from the sun.

What is the Coriolis Effect?

the rotation of Earth causes winds to be deflected to the right in the Northern Hemisphere, and to the left in the Southern Hemisphere

mixed tidal pattern

two high tides and two low tides each day, but the amount of water at each time is different - Pacific Coast of the US