Air & Sea Interactions
Points to Remember Water takes longer to
heat up and cool down due to hydrogen bonds
Points to Remember Warm air can hold more water vapor than cold air
Points to Remember Uneven heating of the Earth’s surface leads to
wind/convection
Points to Remember Global Wind Patterns:
o Doldrumso Trade Windso Westerlieso Easterlies
Points to Remember The Coriolis Effect will cause northward and
southward traveling objects/wind to have a perceived curved trajectory
Points to Remember Global Conveyor Belt’s movement is based on
salinity and temperature differences.
Atmospheric Circulation Cells
Six distinct air masses (three in each hemisphere) with individual airflow patterns
Hadley Cells Air rises from equator
(doldrums) Moves towards the poles
due to convection Sinks at 30 degrees
latitude due to cooling and moisture loss (creates deserts)
Moves back towards the equator
Bends right as it heads towards the equator creating Trade winds
Ferrel Cells Some air that rose
at the equator continues towards the poles
Bends to the right creating the Westerlies
Polar Cells Warm air rises at 60
degrees latitude and flows towards to the poles
It cools and descends at the poles and heads back towards the equator, deflected right to form the polar easterlies
Intertropical Convergence Zone
Vertical motion of the air near the equator that releases large amounts of heat and moisture into the atmosphereo Strongly influences climate, weather, and the seasonso Constantly shifting above and below the equator due to
land masseso Atmosphere circulation symmetrical above and below
the ITCZ not the equator
Intertropical Convergence Zone
El Nino Southern Oscillation
El Nino - A build up of warm water in the oceans near the equator just east of Asia which leads to global weather and climate changes
Occurs every three to eight years
Normal Conditions: Trade winds blow strongly along the equator,
winds blowing parallel to South American coast creates a rising thermocline called an upwelling (rising of nutrient rich/cold seawater)
Normal Conditions: Upwelling makes the temperature of surface water cooler Warm water builds up in Western Pacific Results in low pressure and high rainfall in Western Pacific
(Southeast Asia) and high pressure and low rainfall in Eastern Pacific (Americas)
El Nino Conditions Trade winds weaken, stop or reverse course (blow
East) Warm water that is normally pushed west now
spreads out into the ocean and towards the East Thermocline deepens as a result and upwelling
does not reach surface with cold water, causing Eastern Pacific to be warmer
El Nino Conditions Since there is less of a temperature difference between the
Western and East Pacific, trade winds become even more weak Results in more rain and warmer temperatures in the Americas Arrives around Christmas time (called the current of the little
boy/Christ child, hence the name El Nino) Loss of nutrients from the loss of upwelling collapses the fishing
industry and marine ecosystems
Global Effects of El Nino
Causes the hottest part of the troposphere to move 1/3 around the world
Leads to extensive extreme weather conditions, flooding, tornados, and drought
Destroys ecosystems
La Nina After an El Nino, the normal conditions return in
extreme forms leading to colder than normal ocean conditions in the Eastern Pacific
Monsoons Seasonal wind pattern changes caused by
heating or cooling on the continents that lead to predictable times of massive rainfall or dry conditionso Results in summers with significant rainfall and winters
with very littleo Caused by air heated by landmass rises and is replaced
by warm, moist air from the ocean, which in turn rises and causes rainfall, Cycle reverses in winter
Cyclones Large rotating storm centers of low pressure air,
with converging winds at the center, known as hurricanes (Asia – Typhoons)
Two Types:o Tropical –cyclones that form within a single atmospheric
cello Extratropical – cycles that form in high latitudes, not as
severe, lead to “nor’easters”
Tropical Cyclones Moist winds get drawn
into a low pressure area (air moves from high to low pressure)
The Coriolis Effect causes the winds to spiral inward and counter clockwise in the Northern Hemisphere
Warm air rises in the center via convection causing rain
Tropical Cyclones The formation of rain heats the atmosphere which
causes air pressure to continue to decrease and pull more air into the system
So long as there is moisture and heat, the process continues to intensify, possibly into a hurricane
Simple Explanation1. The sun heats the ocean, the ocean heats the
air, the air rises2. Warm air is less dense and therefore it rises and
thus it has a low pressure3. As the moist air rises, it condense and forms
clouds and precipitation4. Air rushes in to replace the air that rose, and
brings with it more heat and moisture5. The air rushing in deflects to the right due to the
Coriolis Effect causing a counter-clockwise rotation
6. This leads to a tropical cyclone
Hurricane Recipe: Area of warm water Winds affected by the Coriolis Effect (no
hurricanes at the equator nor can they cross the equator)
A collection of storms
Tropical Cyclone Designations
Tropical Disturbance – a low pressure system with a group of storms, little to no rotation
Tropical Depression – A tropical cyclone with max sustained winds up to 38 mph
Tropical Storm – A tropical cyclone with max sustained winds of 39-73 mph (naming stage)
Hurricane – A tropical cyclone with max sustained winds of 74-110 mph
Major Hurricane – A tropical cyclone with max sustained winds of 111+ mph, Category 3 or above
Path of a Hurricane Trade winds direct it
initially to the west, then as it increases in latitude, Westerlies will push it East
Saffir-Simpson Scale Categories of hurricanes are determined by wind
speed and air pressure. The resultant of which determine storm surge and potential damage
Naming System Named alphabetically Alternate boy/girl Retire names of the worst storms