The Oceans

Ocean-Atmosphere Links Exchange of water, carbon dioxide (gases) and heat. Surface currents are driven by atmospheric circulation.

Surface Currents

Transfer heat from one place to another. Keep the upper 100 meters of the ocean well mixed. The Ocean is Stratified

Oceans and Climate Heat transferred from the Equator towards the poles. Example: England has a relatively warm climate at a latitude of Northern Canada.

Thermohaline Circulation

Driven by Density Differences, difference in temperature and salinity. Completes cycle in 6 yrs.

Waves move energy, not water Important Parts Wave length Crest Trough

Breakers Waves break when wave base = ½ wave length

Rip Current (Rip Tide)

Longshore Sediment Transport

Barrier Islands

Current Sediments East Coast

Wave Refraction Waves bend as they approach a headland

Wave Refraction Creates Sea Arches and Sea Stacks

This great double arch is in the Shetland Islands. The Islands, are the northernmost outposts of the United Kingdom and lie N.E. of northern Scotland. Land's End is the westernmost part of England. The arch is near Cornwall about 10 miles from Penzance. Copyright ©2005 Bob Fagley

Tides

Deserts

What is a desert? Less than 250 mm (10 inches) of precipitation. Generally lacking in vegetation. Cannot support a large population ??

Types of Deserts (5) Controlled by air circulation Subtropical – Centered around 30 o N and S latitude Geographically extensive

Global Atmospheric Circulation

Examples: Sahara and Great Australian Subtropical Desert

Types of Deserts Continental Interior- Far from sources of moisture (ocean)

Example: Gobi in Mongolia Continental Interior Desert

Types of Deserts Rainshadow- Mountain ranges cause barrier to flow of moisture.

Rainshadow Desert Examples: Cascades and Sierra Nevada

Types of Deserts Coastal Desert - Cool dry air blows in from the ocean and evaporates occurs as it warms.

Example: Coast of Chile and Peru Coastal Desert

Types of Deserts Polar – Cold air holds very little moisture. What little precipitation falls remains as ice for 1000's of years. Examples: Greenland and Antarctica

Erosion by Wind Abrasion – airborne particles chip off small fragments of other rocks.

Ventifacts

Erosion by Wind Deflation – removal of small, loose particles. Can form desert pavement.

Deposition by Wind Dune – hill or ridge of sand deposited by winds.

Dune Types Dependent on: Sand supply Wind velocity Variability of wind direction Surface over which the dune moves

Limited amounts of sand Barchan - wind from one direction Star - wind direction varies Longitudinal - Wind converges from two directions Abundant sand Transverse - wind from one direction Parabolic – wind blows in land on shores Sand Dune Summery

Barchan - Sand is limited, steady wind from one direction

Longitudinal (Linear) - Limited sand supply, strong converging winds

Star - Sand scarce, wind shifts

Transverse - Abundant sand, moderate wind

Parabolic - Abundant sand, strong offshore wind

Limited amounts of sand Barchan - wind from one direction Star - wind direction varies Longitudinal - Wind converges from two directions Abundant sand Transverse - wind from one direction Parabolic – wind blows in land on shores Sand Dune Summery