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
Thermohaline Circulation
Driven by Density Differences,difference in temperature and salinity.
Completes cycle in 6 yrs.
Waves move, not
water
Important Parts
Wave length
Crest
Trough
Breakers
Waves break when wave base = ½ wave length
Longshore Sediment Transport
Current
Sediments
East Coast
Wave Refraction
Waves bend as they approach a headland
Wave RefractionCreates
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
Copyright ©2005 Bob Fagley
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 30o N and S
latitude
• Geographically extensive
GlobalAtmosphericCirculation
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
Sediment Transport
Sediment Transport by Wind
1. Surface creep2. Saltation3. Suspension
Erosion by WindAbrasion – airborne particles chip off
small fragments of other rocks.
Erosion by WindDeflation – 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
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 directionStar - wind direction variesLongitudinal - Wind converges from two directions
Abundant sand
Transverse - wind from one directionParabolic – wind blows in land on shores
Sand Dune Summery