Option unit B Geo

normal conditions

trade winds blowing from the east to the west along the equator

upwelling of cold, nutrient rich water from deeper levels off the northwest coast of South America

sea surface temperature is about 8°C higher in the Western Pacific than the waters off South America

El Niño

•The trade winds decrease in strength when the air pressure patterns in the South Pacific are reversed

Normal flow of water away from South America decreases . This pushes the thermocline deeper and decreases upwelling

The sea surface temperature increases *to greater than normal (~3 degrees)* in the Eastern Pacific

La Niña

•The trade winds that blow west across the tropical Pacific are stronger than normal

Increased upwelling off South America and hence the *lower than normal* sea surface temperatures

The prevailing rain pattern also shifts farther west than normal

Eye

It is the calm part of the storm.

eye wall

This part has the strongest winds and rains (can be up to 200 miles per hour!)

Rain bands

the clouds that spin out and make the storm bigger.

soft rock

* sandstone
* limestone
* clay
* marl

hard rock

* granite
* basalt
* schist
* gneiss

concordant coastline

the bands of differing rock types run **parallel** to the coast.

The outer hard provides a protective barrier to erosion of the softer rocks further inland.

discordant coastline

differing rock type run perpendicular to the coast.

The differing resistance to erosion leads to the formation of headlands and bays.

constructive waves

have a strong swash and a weak backwash. deposition is greater than erosion

destructive wave

have a weak swash and a strong backwash. erosion is greater than deposition

fetch

the stretch of ocean water of which the water has blown

erosion

the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location

weathering

Weathering breaks down and loosens the surface minerals of rock so they can be transported away by agents of erosion

landform

A natural feature of the earth's surface

hydraulic action

the sheer force of water crashing against the coastline causing material to be dislodged and carried away by the sea

hurricanes/tropical cyclones

low pressure systems that bring heavy rainfall, strong winds and high waves, and cause other hazards such as floods and mudslides

only forms in warm waters near the equator

warm air rises causing an area of lower air pressure below

hurricanes/tropical cyclones formation

• air from surrounding areas with higher air pressure pushes in to the low pressure area

• that “new” air becomes warm and moist and rises too

• as the warm air continues to rise the surrounding air swirls in to take its place

• as the warmed, moist air rises and cools off, the water in the air forms clouds. the whole system of clouds and wind spins and grows, fed by the ocean’s heat and water evaporating from the surface

impacts of hurricanes

hurricane classification using the saffir-simpson scale

tropical cyclones usually weaken when they hit land, because they are no longer being “fed” by the energy from the warm ocean waters. However they often more far inland dumping many inches of rain and causing lots of wind damage before they die out completely

hurricane prediction

hurricane forecasts traditionally focused on predicting a storm’s track and intensity.

hazard mitigation

• urban planning laws

• emergency planning

• relief operations

• evacuation measures

oceanic carbon cycle

• biological processes such as photosynthesis turns carbon dioxide into organic material

• gradually organic carbon settles into the deep ocean

• the upper ocean therefore has a lower concentration of carbon than the deep ocean

• if carbon on the ocean floor was lifted to the surface (as in a thermohaline circulation) the ocean could become a source of CO2 rather than a sink

ocean acidification

poses a threat to shell forming organisms like corals and calcifying plankton, because in a more acidic ocean these creatures will not be able to create their shells and grow

lithology

the type of rock that makes up the coastal materials

geological structure

the disposition and nature of the materials in the coast