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OCEANOGRAPHY II NOTESMRS. BURKEY

EARTH SPACE SCIENCE – CY CREEK HS

TIDES

• THE RISE AND FALL IN SEA LEVEL IS CALLED A TIDE.

•CAUSED BY A GIANT WAVE.

•AVERAGE LOW-TIDE/HIGH-TIDE CYCLE TAKES ABOUT 12 HRS AND 25 MIN.

TIDAL RANGE

• IS THE DIFFERNCE IN OCEAN LEVEL BETWEEN HIGH AND LOW TIDE.

• EX: HIGH TIDE= 25FT LOW TIDE= 20FT TIDAL RANGE= 5FT

HIGH TIDE= 20FT LOW TIDE= 7 FT TIDAL RANGE= 13FT

HIGH TIDE= 30FT LOW TIDE=20FT TIDAL RANGE= 10FT

GRAVITATIONAL EFFECT OF THE MOON

• TWO BIG BULGES OF WATER FORM ON

THE EARTH:

•ONE DIRECTLY UNDER THE MOON

•ANOTHER ON THE EXACT OPPOSITE SIDE

•AS THE EARTH SPINS, THE BULGES

FOLLOW THE MOON.

GRAVITATIONAL EFFECT OF THE SUN

1. SPRING TIDES

• EARTH, MOON, AND SUN ARE LINED

UP

•HIGH TIDES ARE HIGHER AND LOW

TIDES ARE LOWER THAN NORMAL

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GRAVITATIONAL EFFECT OF THE SUN

2. NEAP TIDES

• EARTH, MOON, AND SUN FORM

RIGHT ANGLES

•HIGH TIDES ARE LOWER AND LOW

TIDES ARE HIGHER THAN NORMAL

TIDAL PATTERNS• DIURNAL

• ONE HIGH AND ONE LOW TIDE EACH (LUNAR) DAY

• SEMIDIURNAL

• TWO HIGH AND TWO LOW TIDES OF ABOUT THE SAME HEIGHT DAILY

• MIXED

• CHARACTERISTICS OF BOTH DIURNAL AND SEMIDIURNAL WITH SUCCESSIVE HIGH AND/OR LOW TIDES HAVING SIGNIFICANTLY DIFFERENT HEIGHTS

Variations in tidal form world wide

VARIABLE TIDES

DATUM - A REFERENCE

FROM WHICH MEASUREMENTS ARE MADE.

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MONTHLY TIDAL CURVES

Figure 9-16

Bay of Fundy

High tide

Low tide(6 hours later)

Video Clip:http://www.youtube.com/watch?v=qfhNjpu_IU4

BATHYMETRY“BATHY” = DEEP/DEPTH“METRY” = TO MEASURE

THE STUDY OF UNDERWATER DEPTH

FEATURES ON THE OCEAN FLOOR

http://www.ngdc.noaa.gov/mgg/image/2minrelief.html

SONAR• SOUND NAVIGATION AND RANGING

• TECHNIQUE THAT USES SOUND PROPAGATION TO NAVIGATE, COMMUNICATE WITH OR DETECT OBJECTS ON OR UNDER THE SURFACE OF THE WATER.

• PROVIDES A QUICK WAY OF LOOKING THROUGH WATER TO IDENTIFY FEATURES IN AND UNDER THE WATER (FISH, SANDBARS, ETC.)

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Gravitation Detection - local direction of gravitybased on attraction to underwater mountains.

HTTP://MARINE.USGS.GOV/FACT-SHEETS/FS172-97/MAPPING.HTML

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1. CONTINENTAL SHELF

• SUBMERGED EDGE OF CONTINENT

• GENTLE SLOPE AWAY FROM SHORE

• RESOURCES!

(GAS, OIL, GRAVEL, FISHING!)

2. CONTINENTAL SLOPE

• STEEP!

• TRANSITION FROM SHELF TO DEEP

OCEAN FLOOR

3. CONTINENTAL RISE

• MEDIUM STEEP...

• SEDIMENT THAT COLLECTS AT

BOTTOM OF SLOPE

Continental Margin

SUBMARINE CANYONS• CUT INTO CONTINENTAL SHELF & SLOPE!

• MOST CAUSED BY EARTHQUAKES

http://oceanexplorer.noaa.gov/explorations/deepeast01/background/dumping/media/dumping1.html

OCEAN BASIN FLOOR

1. DEEP-OCEAN TRENCHES• SUBDUCTION ZONES

• SUPER DEEP! (>10,000M)

2. ABYSSAL PLAINS• FLATTEST PLACES ON EARTH!

• COVERED IN SEDIMENT

3. SEAMOUNTS• SUBMERGED VOLCANOES

4. GUYOTS• INACTIVE SEAMOUNTS

• FLAT TOP FROM EROSION

5. ISLAND• ABOVE GROUND SEAMOUNT

SeamountIsland

GuyotAbyssal Plains

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OCEAN RIDGES• DIVERGENT PLATE BOUNDARY

• MOUNTAINOUS CHAIN OF YOUNG VOLCANIC

ROCK

• SITE OF HYDROTHERMAL VENTS

ATOLLS

• RING-SHAPED ISLANDS OF

CORAL REEFS

• FORM ON SUBMERGED INACTIVE

VOLCANOES

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OCEAN – ATMOSPHERE CIRCULATION (REVIEW SECTION)

• SOLAR RADIATION HEATS THE SURFACE CAUSING DIFFERENTIAL

HEATING.

• HIGH AND LOW PRESSURE AREAS FORM.

• AIR WILL RISE & SINK CAUSING CONVECTION CURRENTS IN THE

ATMOSPHERE.

• DIFFERENCES IN PRESSURES CAUSE WINDS TO BLOW.

• SEA SURFACE WINDS CAUSE SURFACE CURRENTS ON THE OCEAN.

• SALINITY AND TEMPERATURE CAUSE THE DEEP OCEAN CURRENTS.

OCEAN – ATMOSPHERE CIRCULATION

SEA SURFACE TEMPERATURE

http://www.ldeo.columbia.edu/dees/ees/climate/slides/sst_march.gif

OCEAN SALINITY

http://www.ldeo.columbia.edu/dees/ees/climate/slides/sal_march.gif

•http://ingrid.ldgo.columbia.edu/

El NinoLa Nina

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EL NINO? (WARM)

• TRADE WINDS WEAKEN

• THERMOCLINE DROPS

• UPWELLING IS CUT OFF

• SST RISES IN E.PACIFIC

• HIGH & LOW PRESSURE AREAS

IN PACIFIC REVERSE

• DISRUPTS FISH/BIRD

POPULATIONS IN E.PACIFIC

• OCCUR EVERY 2-7 YEARS

• LASTS 12-18 MONTHS

LA NINA (COLD)

• TRADE WINDS

STRENGTHEN

• SST DECREASE IN E.PACIFIC

• UPWELLING INCREASES

• OCCURS EVERY 3-5 YEARS

• LASTS 9-12 MONTHS

• PRENTICE HALL TEXTBOOK ANIMATION LINK • PRENTICE HALL TEXTBOOK ANIMATION LINK

• PRENTICE HALL TEXTBOOK ANIMATION LINK • PRENTICE HALL TEXTBOOK ANIMATION LINK

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SST- (SEA SURFACE TEMPERATURE) DIFFERENCES BETWEEN EL NINO AND LA NINA

A

B

C

QUIZ! WHICH IS WHICH…NORMAL, EL NINO, LA NINA?

WERE YOU’RE PREDICTIONS CORRECT?

WHAT ARE THE EFFECTS OF EL NINO?

BRUSH FIRES CAUSED BY DROUGHTINCREASED TROPICAL STORMS

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DEVASTATING FLOODSHURRICANES

• EL NIÑO CONTRIBUTES TO MORE EASTERN PACIFIC HURRICANES AND FEWER ATLANTIC HURRICANES.

• LA NIÑA CONTRIBUTES TO FEWER EASTERN PACIFIC HURRICANES AND MORE ATLANTIC HURRICANES.

US hurricane damage

TORNADO ACTIVITY

DEPENDS ON THE LOCATION OF THE POLAR JET STREAM

• EL NINO: MORE TO THE SOUTH

• LA NINA: MORE TO THE NORTH

MEASUREMENTS!

How can we predict an El Nino or La Nina event?

BUOYS

MEASURES...

• TEMPERATURE

• CURRENTS

• WINDS

RADIOSONDE

• WEATHER BALLOON

• MONITORS GLOBAL

WEATHER AND CLIMATE

PATTERNS

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SATELLITESPROVIDE DATA ON:

• RAINFALL

• WIND

• OCEAN TEMP.

• SEA SURFACE

HEIGHT

• OCEAN COLOR

• SURFACE CURRENTS

TOPEX/POSEIDON (T/P)