OCEANS

Hypsometric Curve

EUSTATIC SEALEVEL CONTROLS

LOCAL SEALEVEL CONTROLS Subsidence Tectonism (mtn building) Isostatic adjustment

GROUP PRS Why is sealevel in Sitka falling? Mountain building B. Distance to equator C. Glacial melting D. Mid-ocean spreading E. Local subsidence

Greenland ice melts = 5 m rise

What impact would a .5-1 m sealevel rise have on the US? Given that we may not know how much it will rise for another 20-30 years, what if anything, do we do now?

OCEANS TIDES

Spring Tides Neap Tides

PRS If the moon was twice as far away the tides would be A. Larger B. Smaller C. No change

Tides affected by shoreline shape

Tides affected by latitude

PRS If the Bay of Fundy was on the equator how would the highest tides be affected? A. Higher B. Lower C. No change

WAVES

Generated by wind speed, duration, fetch Wavebase = ½ wavelength

Shore profile is dynamic equilibrium

Wave Refraction waves bend toward slower medium

Wave energy focused on headlands = erosion Wave energy dispersed in bays = deposition

Wave refraction generates longshore current

Creates Spits Alligator point

PRS Which way is the longshore current flowing? To the North B. To the South C. To the East D. to the West E. Can’t tell

Barrier Islands How formed? Cutoff Spit Drowned Dunes Exposed Sand Bar

PRS Overwash causes barrier islands to move in which direction? Toward shore B. Toward the ocean C. Parallel to the coast

Coastal Engineering Seawalls

Beach Armor – Rip-Rap

Groins, jetties

Which way is the longshore current flowing? PRS Which way is the longshore current flowing? A. To the North B. To the South C. To the East D to the West E. Can’t tell

Beach Nourishment

GROUP PRS Why has the southern part of the island migrated onshore? Change of wave direction Development on southern island Rise in sealevel Inlet jetties Change in longshore current

Rip Currents

Convection

ITCZ = Inter Tropical Convergence Zone - Low pressure Rising air cools and rains

Note the pronounced shift in the ITCZ over India. What causes this?

PRS The shift is caused by Plate tectonics B. Eccentricity in earth’s orbit C. Atmospheric CO2 D. Asia E. Human interference

Coriolis effect

Convection cells and zonal wind flow