Oceanography Notes Midterm Corrections



Download 177.02 Kb.
Page3/3
Date18.10.2016
Size177.02 Kb.
1   2   3

density and salinity remain mostly unchanged in deep ocean



temperature-salinity diagram: identify deep water masses by temperature, salinity, and density.

isothermal water column makes for easier up and down welling.



Antarctic bottom water: formed under sea ice in s subpolar lats in Antarctic continental margins. Sink down Antarctica continental slope. Densest water in open ocean. spreads into all ocean basins. returns to surface in 1000yrs.

North Atlantic Deep Water: from: Irminger Sea, Labrador Sea, Med Sea, Norwegian sea. moves to all ocean basins. less dense; sits on top of Antarctic bottom water

no sinking at subtrop convergences



arctic convergences: mass sinking occurs

antartic intermeiate water: formed sinking at Antarctic convergence. ;east studied water mass.

no vertical mixing at low lat, much vertical much at high lat



ocean common waters: mix of antarctic bottom water and north atlantic deep water. lines basins of Indian and pacific oceans because no access to N hemis deep water.

surface water of pac to salin to sink, Indian too warm to sink

difficult to identify where verticle flow to surface occurs. every liter water that sinks much rise

supposedly greater in low lat areas

also, deep water moving along rugged topography produces upwelling

most intense deep water flow along western side due to coriolis and bathymetric features



conveyer belt circulation: model combing deep and surface currents

cold water dissolve more oxygen than warm water.

in past, warm water probably was more a part of deep water

conveyer belt circulation initiated in Atlantic.



Chapter 7 Online Wrong

    • ocean currents driven and energized by solar heat

    • transfer 30% heat from tropics to poles

    • West Wind Drift part of: North pac gyre, S Atl gyre, Indian gyre

    • Surface water does NOT move at angle to wind direction

    • Ekman transport results in water piling at center of gyre

    • areas with well-developed pycnocline have little downwelling

    • NOT result of El Nino climate:

      • inc water temp/destruction coral in E pac

      • inc sea lvl E pac

      • more hurricanes E pac

    • cold downwelling water=100 amazon river volumes.


Chapter 8

    • disturbing force: energy that cause ocean waves

      • -rock thrown into pond: release of eng causes waves

    • wind generates most waves; radiate in all directions

    • waves created between fluids [water, air] and within them

    • ocean waves: air-water interface [movement air across ocean]

    • atmospheric waves: air-air interface. movement of different air masses. common at cold fronts. ripple-like clouds

    • internal waves: water-water. movement of different water densities, along boundaries. associated with pycnocline. larger than ocean waves. can be seen from space. dangerous for submarines. can’t “break” except in essence. created by tidal movement, turbidity currents, wind stress, passing ships.

    • sea floor movement->large waves

    • waves are energy in motion. the energy moves within them but does not affect their movement.

    • progressive waves: oscillate uniformly, travel without breaking: longitudinal, traverse, orbital

      • longitudinal waves: [push-pull waves] particles push and pull in same direction the the energy travel

      • sound is longitudinal waves

      • longitudinal can be in all forms of matter

      • traverse waves: [side to side] eng travel at right angles to direction of vibrating particles

      • rope to doorknob, wave rope up and down to produce waves

      • traverse only through solids

      • longitudinal and traverse waves called body waves

      • ocean waves are body waves, and since they involve aspects of longitudinal waves and traverse waves, they are orbital waves

    • sine waves: idealized waveforms that do not exist in nature

    • crests: high parts of waves

    • trophs: low parts of waves

    • still water lvl: halfway b/w crest and troph. zero energy lvl. lvl of water if not waves

    • wave height [H]: verticle distance b/w crest and troph

    • wavelength [L]: crest to crest. troph to troph.

    • wave steepness: ratio of height to wavelength-> H/L

    • wave period [T]: time for 1 wavelength to pass a fixed position. typically 6-16s

    • frequency: 1/T

    • circular orbital motion: water moving in a circular motion to pass wave energy along

    • floating objects move up and back as crest approached

    • up and forward as it passes

    • down and forward after it passes

    • down and back as troph approaches.

    • so, object moves in a circle to return to a spot slightly forward of its original position

    • wave drift: orbit in the troph is slower than at the crest. accounts for slight forward movement.

    • water particles orbit but waves more forward

    • circular orbit of an object at surface has diameter=wavelength

    • wave base: where circular orbital movement is negligible= L/2, measured from still water lvl.

    • longer the wave, deeper the base

    • easier to swim below waves than to fight them at the surface

    • deep water waves: if water depth [d]> L/2. have no interference with ocean bottom

    • wave speed [S]: rate at which a wave travels L/T. celerity

      • celerity used only in relation to waves no mass moving, just wave form

      • speed depends on wavelength

      • longer the wavelength, faster the wave travels

      • so, fast wave not neceissarily have great height, b/c S only dependent on L

    • shallow water waves: wave with d<1/20 of L. long waves S=d/T

      • ocean floor interferes with their orbital motion

      • speed of these waves influenced by gravitational acceleration [g] and depth [d]. mostly by depth

      • deeper the water, faster the wave

      • include: tsunami, tides, and wind-generated waves moved into shallow nearshore areas.

      • tsunami, tides very long L [greater so than ocean depth]

      • particle movement: flat elliptical orbit

    • transitional waves: some characteristics of shallow and deep water waves. L b/w 2 and 20 times the water depth. Speed depends on L and d.

    • wind creates pressure, stress

    • capillary waves: L-1.74cm. ripples. small, rounded, v-shaped troph

    • restoring force: destroy capillary waves, restore smooth surface. Capillarity dominant

    • gravity waves: symmetric waves with L>1.74cm. gravity more dominant restoring force. L is 15-35x their height. trochoidal waveform.

    • Sea”: where wind-driven waves are generated. choppy, many direc.

    • energy in waves: 1] wind speed 2] duration [of wind in 1 direction] 3]fetch [distance wind blows]

    • whitecaps: open ocean breakers

    • Beaufort Wind Scale: describes all appearances of sea

      • sir Francis Beaufort of British Navy

    • Ramapo and wave H 1935

    • fully developed sea: equilibrium condition. when waves can no longer grow

    • swells: long-crested part of “sea.” waves that have traveled out of their area of origination

      • reason for waves at windless shore

    • wave trains: groups of waves that follow out of the sea area the faster waves

    • wave dispersion: the sorting of waves by their L

    • longer waves outrun shorter waves

    • decay distance: distance waves change from choppy sea to uniform swell. can be hundred miles

    • as train moves, front wave disappears over and over, but # of waves remain, b/c new wave forms in back of train

    • train moves at ½ velocity of any individual wave in group, b/c of this progression

    • interference patterns: swells from different storms run together. sum of disturbance that each wave would have produced individually.

      • constructive interference; wave with same L->crest to crest, troph to troph-> height increases

      • destructive interference: wave with same L->crest to troph->height decreases

      • mixed interference: different L

        • surf beat: varied sequence of high and lower waves

    • surf zone: zone of breaking wave at continental margins

    • shoaling: becoming shallower

    • any sunken obstacle causes waves to lose energy

    • breaking wave indicates shallow water

    • wave speed decreases as water shoal. L decreases. H increases. increase wave steepness [breaks at 1/7]

    • swell from far off storm break near shore. parallel lines of uniform breakers

    • local wind waves not swell break further off shore; rough, choppy, irregular

    • depth of water where waves breaking is 1.33x breaker height

    • waves break in surf zone because particle motion at bottom of wave restricted

      • bottom wave slower than top, which subsequently topples over

    • rogue waves: unusually large waves

    • spilling breaker: turbulent mass of air and water running down slope of wave. low overall eng. result at gently sloped ocean bottoms. long, boring surfing.

    • plunging breaker: curling crest move over air pocket. particles in crest outrun the wave. form on steep beach slopes.

    • surging breaker: build up and break right at shoreline. caused by abrupt slope.

    • refraction: bending of each wave crest as wave approaches shore

    • waves bend almost parallel to shore

    • refratction of waves along irregular shoreline distributes wave energy unevenly along shore

    • orthogonal lines: wave rays. indicate direction waves travel: spread so that energy between lines is equal at all time.

      • -converge on headlands jutting into sea

      • -diverge in bays

    • wave reflection¨: wave reflected back into ocean with min loss of eng. reflected most often at angle.

    • the wedge: W of jetty that protects harbor entrance at Newport, Cali.

    • standing waves: stationary wave. produced by waves reflecting at 90 deg. sum of 2 waves with ame L traveling in dir directions. no circular motion.

    • nodes; no movement. horizontal

    • antinodes; movement. vertical

    • tsunami: large destructive waves. NOT tidal waves. seismic sea waves

      • most cause by fault movement; vertical, not horizontal displacement.

    • splash waves: above water landslides or meteor impact tsunamis

    • tsunami L-125miles avg can be felt 62 miles deep. S=435mph in opean ocea. 5meteres high

    • they are more like an increase/decrease in sea lvl than a breaking wave

    • typically are a series of waves. largest surface in generally the later surge

    • extremely large/destructive every 15-20years. 57 noticeable tsunami per decade. 86% in pacific.

      • Krakatu eruption [1883] 36k dead from tsunami.

    • Pacific Tsunami Warning Center [PTWC]: coordinates infor from 25 pacific rim countries. HQ in hawii. 50 measuring stations

    • tsunamigenic->capable of producing tsunami

    • transform faults do not create tsunami

    • best to move ships out to sea open ocean

    • 10 megawatts per .6m of shoreline with wave power harnessing

    • LIMPET 500: 1st commercial wave power plant. 2000

    • more wave energy along W coast than E coast. largest waves associated with prevailing westerlies.


Chapter 8 Wrong

    • internal wave occur at strong steady pycnocline most

    • tsunami from Hawaii 5 hours to reach W coast.

    • surf zone is where waves are actively breaking

    • velocity of wave decreases once it touches bottom

    • wave fronts of storms are beyond the “limit of the storm”

    • storms and tidal movements are also disturbing forces

    • ocean waves cannot: be described by the way they form, be described by T, L, H, and not by the way they form

    • Orbital waves=Swell!!!!!

    • ocean waves are oribital waves

    • body waves: longitudinal and traverse

    • 1 meter high tsunami with a bigger wave base than 1000m long wave

    • we can determine S if we know L, T, F

    • either interferences [destruc, construc] caused by either refraction or reflection




Chapter 9

tides: periodic raising and lower of avg sea lvl.

450 BC Hertodotus observe tides in writing.

Issac Newton 1642-1727 universal law gravitation

barycenter: 1k miles beneath surface earth. earth and moon rotate around these.

gravity pulls all water on earth to moon and sun

tides generated by forces imposed on earth generated by combination of gravity and motion among earth, moon and sun

gravitational force: derived from Newton’s law: every particle of mass in the universe attracts every other particle

if mass increases, gravitational force increases

if distance increases, gravitational force greatly decreases

the greater the mass of objects and the closer they are, the greater they attract



zenith: pt closest to moon, greatest grav attraction

nadir: pt furthest from moon, weakest grav attraction

at angles. causing grav attraction b/w each particle and moon be slightly different



centripetal force: required to keep planets in orbit. inward center-seeking force. provided by grav attraction b/w planets and sun

broken string, ball flies tangent to orbital pattern

gravity supplies centripetal force

particles identical mass rotate in identical sized paths due to E moon rot sys

each req identical centrip force to maintain circular path

supplied force: [gravitational attraction between particle and moon] dif from

required force [b/c grav att varies with ditance from moon]

resultant forces: b/c of above difference. the mathematical dif between two sets of arrows [centripetal force=req force; gravitational force=supplied force]

red arrow to black area at pt of beginning

avg 1 million the magn E grav

if res force vertical; at nadir and zenith arrow outward, and along “equator” N and S arrows downward. no tide effect



tide-generating forces: if resultant force significant horizontal to E surface: produce tidal bulges. small forces, but max at 45deg relative to NS “equator”

gravitational attraction inversely proportionate to the square of the distance between two masses.

tide-gen force inversely proporationate to the ccube of the distance between each point on earth and center of moon or sun

distance more highly weighed variable for tide-gen force

tide-gen force pushes water into bulges oat zenith and nadir [Lunar bulges]

side facing moon bulge is because grav force>centripetal. side away from moon is because centripetal>grav force.

bulges are equal. all pts on earth experience 2 tides per day except the poles

atmospheric tides: can be miles high. solid-body/Earth tides: within interior of Earth; stretch skin of earth by centimeters

there is tide in glass of water



tidal period: time b/w each tide [2 per day] 12 hours ideally at equator

lunar day: 24hr 50m, moon overhead to overhead

solar day: 24hr, sun overhead to overhead

moon rises 50min later each day, high tides occur 50 mins later each consecutive day.



solar bulges: caused by sun; at closest and furthest distance from thereof

sun 27mx bigger than moon

sun tidal attract is less than moon because sun is 390x farther from earth

solar bulges 46% of lunar bulges



flood tide: tides appear move toward shore

ebb tide: away shore

but; earth’s rotation carries various location into and out of the tidal bulges, which are fixed relative to sun and moon

monthly tidal cycle 29.5 days; this is how long it take moon to orbit earth

new moon: moon between earth and sun; can’t be seen at night/ conjunction

full moon: moon opposite side of sun. fully visible. opposition

quarter moon: half lit half dark. moon at 90 deg angles with E relative to sun

tidal range: vertical difference between high and low tides

very large at new and full moons



spring tide: max tidal range. 2x per month

syzygy: call the moon during full and new.

at quarter moon, lunar/solar tide working at right angles



neap tide: small tidal range; destructive interference

quadrature: call the moon at quarter moon

time b/w spring tides or neap tides is ½ monthly lundar cycle: 2 weeks

time b/w spring and neap tides is ¼ monthly lunar cycle: 1 week

waxing crescent: new moon to first quarter moon

waxing gibbous: first quarter moon to full moon

waning gibbous: full moon to third-quarter

waning crescent: third quarter to new moon

moon has synchronous rotation: identical periods of rotation

“blue moon” once every 2.72 years.

declination: angular distance of sun or moon above or below Earth’s equatorial plane

ecliptic: imaginary plane containing the invisible ellipse on which E revolves around the sun.

max declination of sun relative to Earth’s equator is 23.5

plane of moon’s orbit tilted 5deg with respect to ecliptic

so, max declination of moons orbit relative to Earths equator= 28.5

changes dec from N to S during the miltiple lunar cycles within 1 year

so, tidal bulges are rarely aligned with the equator [as is ideal]

earth 92.2million miles from sun during N hemis winter. 94.5 million miles during summer

distance b/w E and sun varies 2.5% over course of year



perihelion: earth nearest to sun. tidal ranges large. January

aphelion: earth furthest from sun. tidal ranges small

greatest tidal ranges in Jan each year

moon around earth elliptical, E-M distance varies 8%

perigee: moon closest to earth. largest tidal ranges

apogee: moon furthest from earth. smallest tidal ranges

moon cycle: perigee, apogee, back to perigee every 27.5 days



proxigean: spring tide coincide with perigee. especially high tides. storms heavy dmg now.

also, spring tide graeter range during N hemis winter

max spring tide once every 1600 yrs

declination of moon determines position of tidal bulges

neither the 2 high or 2 low tides of same H b/c of declination of moon and sun

tidal moves more as forced waves with their speed determined by ocean depth

435mph avg.

bulges don’t exists, because they’re too slow



cells: what ocean tides break up into instead

amphidromic point: near center of each cell, around which crests and trophs of tide wave rotate.

no tidal range here



cotidal lines: radiate from amphidromic point: connects point where high tide occurs simultaneously.

tide wave rotates CCW in N hemis, CW in S hemis

wave complete 1 rotation during tidal period [12 lunar hours] limits size of cells.

low occurs 6 hrs after high in amph cell

high on “10” cotidal line, low must be occurring on “4” cotidal line of cell

inc turbulence and mixing strongly affect tides. tidal waves breaking conts produces internal waves

over 150 factors affect tides at given coast

effect: high tide rarely occurs when moon at apogee. vary place to place

mathematical model beyond limits of scientists

diurnal tidal pattern: single high and low tide each lunar day. tidal period= 24hr 50m.

common in shallow inland seas



semidiurnal tidal pattern: 2 high and low tides each luner day. H of successive H and L tides approx the same, NEVER exactly. tidal period: 12hr, 25m

common along atlantic coasts of us



mixed tidal pattern: character of both above. successive H and L very different H [condition called diurnal inequality]. Tidal period typically 12hr 25m, but can exhibit diurnal period too.

most common type; pac coast N America



bay of Fundy: largest tidal range

rotary current: produced by current rotation CCW in N hemis basin. In open portion of basin

reversing current: moves into and out of restricted passages along coast. caused by increased friction in nearshore shoaling waters. once a rotary current.

rotary currents less .6mph. reversing currents up to 28mph in restricted channels.

rev currents in mouths of bays

flood current: produced when water rush into bay/river with incoming high tide.

ebb current: produced when water drains from bay/river because low tide approaching

high slack water: occurs at peak of each high tide

low slack water: peak of each low tide

during these times, no currents occur more some minutes

reversing currents cause navigational hazards, but prevent sed build-up and replenish bay nutrients

tidal current significant even at depths



whirlpool/vortex: rapidly spinning body of water. cause by rev currents.

most common in shallow passages connecting 2 large bodies water with difference tidal patterns/cycles

up to 10 mph

Maelstrom off N coast Norway is strongest in world



Datum: MLLW; avg of 2 low slack waters

tidal bore: wall of water that moves up low-lying rivers due to incoming tide.

to 5m high/14 mph. develop where large tidal range, loww-lying river exists.

due to resistance of river flow. Chientang River [China] has the largest bore.

grunion: slender silvery fish that spawns on land.

Chapter 9 Wrong

no neap tide during solar eclipse

open ocean tidal current rotary

strongest gravitational force=highest tide

go collecting during spring tide [great tidal range]

ideal high tide interval; 12hr 25m

force of gravity not related to velocity

plane of solar system= eclictic plane

moon over equator will not describe tropical tides

tidal waves are thousands of kilometers, and are deep water waves

centripetal force act perpendicular to the solar gravitational force

side of earth closest to sun, high tides not form due to gravitational forces

tidal forces not greatest at sygyzy

semidiurnal tides result in 2 predicatable lows every day


Chapter 10

US 80% pop coastal

waves crash on most coasts 10k per day

shore: zone between lowest tide lvl and highest elevation on land affected by storm waves

coast: inland from shore as far as ocean-related features can be found

shore and coast greatly vary



coastline: boundary between shore and coast

backshore: above high tide shoreline-> water covered only during storms

foreshore: submerged at high tide, exposed at low tide.

shoreline: water’s edge. follows tide

nearshore: seaward from low tide shoreline to low tide breaker line

-never exposed. affected by waves



offshore zone: beyond low-tide breakers. waves rarely affect bottom

beach: a deposit of the shore area

wave-cut bench: flat, wave-eroded surface

bench is the entire active area of coast that experience changes due to breaking waves



recreational beach: area of beach above shoreline

berm; dry, gently sloping region at foot of coastal cliffs or dunes.

beach face: wet, sloping surface extend from berm to shoreline

more exposed low tide. also called low tide terrace



longshore bars: beyond beach face: 1 or more; sand bars parallel coast. these “trip” water

longshore troph: separate longshore bar from beachface.

notch: between coastline and berm.

order: coastline-notch-berm-high tide shoreline-beach face-low tide shoreline-wace cut bench-longshore troph-longshore bar-low tide breaker line

beach sediment finer from rivers that drain lowland areas than highland areas

mud coasts: Suriname, SW India

beaches: material in transit along shoreline

movement parallel and perpendicular to coast



swash: water from broken wave running up beach face. soaks in.

backwash: drains back. picking up sed

whichever is dominant dictates deposition or erosion

light wave activity – more swash. wide, developed beach

heavy wave activity-less swash, more backwash. New wave swash on top of old wave backwash. removed sand creates bars



Chapter 10 wrong

a beach on low relief tropical island made mostly of calcium carbonate

isostatic rebound CANNOT produce global sea lvl rise

barrier flat is the woodland above the salt marshes, which are closest to lagoon



shore includes from low tide line to notch


COPYRIGHT 2007 BY LITERAL, INC.

Download 177.02 Kb.

Share with your friends:
1   2   3




The database is protected by copyright ©ininet.org 2020
send message

    Main page