TIDES OCEANOGRAPHY II NOTES MRS. BURKEY EARTH SPACE SCIENCE CY CREEK HS 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 1
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 MEASUREMENT S ARE MADE. 2
MONTHLY TIDAL CURVES High tide Bay of Fundy Low tide ( 6 hours later) Figure 9-16 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 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.) http://www.ngdc.noaa.gov/mgg/image/2minrelief.html 3
Gravitation Detection - local direction of gravity based on attraction to underwater mountains. HTTP://MARINE.USGS.GOV/FACT-SHEETS/FS172-97/MAPPING.HTML 4
Continental Margin 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 SUBMARINE CANYONS CUT INTO CONTINENTAL SHELF & SLOPE! MOST CAUSED BY EARTHQUAKES http://oceanexplorer.noaa.gov/explorations/deepeast01/background/dumping/media/du mping1.html OCEAN BASIN FLOOR 1. DEEP-OCEAN TRENCHES SUBDUCTION ZONES SUPER DEEP! (>10,000M) 2. ABYSSAL PLAINS FLATTEST PLACES ON EARTH! COVERED IN SEDIMENT Seamount Island Guyot 3. SEAMOUNTS SUBMERGED VOLCANOES 4. GUYOTS INACTIVE SEAMOUNTS FLAT TOP FROM EROSION 5. ISLAND ABOVE GROUND SEAMOUNT Abyssal Plains 5
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 6
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 OCEAN SALINITY http://www.ldeo.columbia.edu/dees/ees/climate/slides/sst_march.gif http://www.ldeo.columbia.edu/dees/ees/climate/slides/sal_march.gif http://ingrid.ldgo.columbia.edu/ El Nino La Nina 7
TRADE WINDS WEAKEN THERMOCLINE DROPS UPWELLING IS CUT OFF SST RISES IN E.PACIFIC EL NINO? (WARM) HIGH & LOW PRESSURE AREAS IN PACIFIC REVERSE DISRUPTS FISH/BIRD POPULATIONS IN E.PACIFIC OCCUR EVERY 2-7 YEARS LASTS 12-18 MONTHS TRADE WINDS STRENGTHEN LA NINA (COLD) 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 8
SST- (SEA SURFACE TEMPERATURE) DIFFERENCES BETWEEN EL NINO AND LA NINA QUIZ! WHICH IS WHICH NORMAL, EL NINO, LA NINA? A B C WERE YOU RE PREDICTIONS CORRECT? WHAT ARE THE EFFECTS OF EL NINO? BRUSH FIRES CAUSED BY DROUGHT INCREASED TROPICAL STORMS 9
DEVASTATING FLOODS HURRICANES 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 How can we predict an El Nino or La Nina event? EL NINO: MORE TO THE SOUTH LA NINA: MORE TO THE NORTH MEASUREMENTS! BUOYS MEASURES... TEMPERATURE CURRENTS WINDS WEATHER BALLOON MONITORS GLOBAL WEATHER AND CLIMATE PATTERNS RADIOSONDE 10
SATELLITES PROVIDE DATA ON: RAINFALL WIND OCEAN TEMP. SEA SURFACE HEIGHT OCEAN COLOR SURFACE CURRENTS TOPEX/POSEIDON (T/P) 11