Presentation Transcript
The Oceans: The Oceans A Presentation on Atmosphere-Ocean Interaction National Weather Service Shreveport, LA Presented by:
Why study major bodies of water?: Why study major bodies of water? Water covers nearly ¾ of the earth’s surface
More than 50% of the world’s population lives within an hour of the coast
Plays a role in both climate and day-to-day weather
FOOD!
Cost of your food could depend on it
The “Basics”: The “Basics” There are FOUR oceans ATLANTIC
PACIFIC
INDIAN
SOUTHERN
Around the World in 4 Slides…: Around the World in 4 Slides…
Around the World in 4 Slides…: Around the World in 4 Slides…
Around the World in 4 Slides…: Around the World in 4 Slides…
Around the World in 4 Slides…: Around the World in 4 Slides… “Defined” in 2000
Ocean or Sea, What’s the Big Deal?: Ocean or Sea, What’s the Big Deal? SEAS
Delineated by land masses
Doesn’t matter if they’re largely enclosed
Also “communicate” with the ocean Black Sea Mediterranean Sea Africa Europe Gulf of Mexico United States Mexico
Bragging Rights…: Bragging Rights… Which ocean is the biggest?
Bragging Rights…: Bragging Rights… Which ocean has the most coastline?
Water is Water…or is it?!: Water is Water…or is it?! FRESHWATER
Rivers
Streams
Lakes SALTWATER
Oceans
Gulfs
Seas
Water is Water…or is it?!: Water is Water…or is it?! QUESTION:
Is saltwater the same everywhere?
ANSWER:
Nope.
In general, the Atlantic Ocean is the “saltiest.”
Please Pass the Salt…: Please Pass the Salt… “Run-of-the-mill” concentration?
3.5 grams/liter
Like weather, there are areas of
HIGH salinity
LOW salinity
So, where are these “highs” and “lows”?
Please Pass the Salt…: Please Pass the Salt… H H H H H L L L
Mmmmm…Salty!: Mmmmm…Salty! DEAD SEA FACTS:
Really a large lake
Water gets in, but not out!
Fed by River Jordan
Evaporation only way out
Has nearly 10 times the salinity of the oceans!
Leads to increased density
So??: So?? The increased
density means
just about anything
will float! We can see this through the use of eggs!
We’re Goin’ Down, Down, Down…: We’re Goin’ Down, Down, Down… Just like the atmosphere, the ocean has layers!
The Epipelagic Zone: The Epipelagic Zone “Sunlight Zone”
Most solar heating
Lots of temperature change
Surface to 200m
Influenced by wind
Bridge Over Troubled Waters…: Bridge Over Troubled Waters… A transition layer
Temperature decreases rapidly
Relevance to you?
Higher bass concentrations (oxygen is just right)
The Mesopelagic Zone: The Mesopelagic Zone “Twilight Zone”
Most temperature change near top of layer
Between 200 and 1000m
Animal characteristics begin to change
The Bathypelagic Zone: The Bathypelagic Zone “Midnight Zone”
No light at all
Only light comes from animals
Very little temperature change
Pressure reaches over 5800 p.s.i.
The Abyssopelagic Zone: The Abyssopelagic Zone “The Abyss”
Greek word meaning “no bottom”
Between 4000 and 6000m
Water temperature near freezing
The Hadalpelagic Zone: The Hadalpelagic Zone “The Trenches”
Anything below 6000m
Worth repeating:
Deepest trench is the Mariana Trench
“Weight”: >8 t.s.i.
Life still exists here! That’s TONS per square inch!
Our Mr. Sun: Our Mr. Sun “Driving Force”
Solar radiation affects the ocean differently
More on this later
Ultimate cause of wind
Ocean Currents – Just the Facts: Ocean Currents – Just the Facts Two types:
Wind-driven Currents
Deep Water Currents
40% of the global heat transport
Move slower than surface winds
Kilometers per day vs. kilometers per hour
Long-term climate impacts
Gulf Stream most important in our region
Ocean Currents -- Development: Ocean Currents -- Development Oceans near equator “heat up” more than the poles
Sets up…
Temperature imbalance
Semi-permanent pressure areas
Constant push of wind on water
Ocean Currents – The Big Picture: Ocean Currents – The Big Picture
The Gulf Stream: The Gulf Stream
Dust in the Wind – During the Day: Dust in the Wind – During the Day Beach heats faster than ocean
Air rises onshore
Slightly cooler, denser air moves onshore to replace the “lost” air
Results:
Onshore breeze
Possible storm development
Dust in the Wind – At Night: Dust in the Wind – At Night Beach cools faster than ocean
Air rises offshore
Slightly cooler, denser air moves offshore to replace the “lost” air
Results:
Offshore breeze
Possible storm development
Wave Action: Wave Action Another byproduct of wind
Size depends on THREE things:
Speed
Duration
Distance
Longer the wave, the faster it moves
Here’s a cool fact:
You can estimate the wind speed using the size of waves
Battle of the Bulge: Battle of the Bulge Tides are another type of wave action
Definition:
A change in the ocean water level, which results from the gravitational pull of the moon
POP QUIZ: POP QUIZ Where are the largest ranges from high to low tide in the world?
Battle of the Bulge: Battle of the Bulge Why the moon?
Sun’s gravitational pull is greater
But the moon is closer
Mariners have known for a long time that tides were related to the moon
Battle of the Bulge: Battle of the Bulge Famous dead people who have studied tidal motion:
Galileo
Descartes
Newton
Laplace
Lord Kelvin
Kepler
POP QUIZ: POP QUIZ Where are the largest ranges from high to low tide in the world? HINT: It’s in North America
Two tides? Four tides?: Two tides? Four tides? Number of tides per day related to…
Shape of the coastline
Sea floor elevation
Some places have one high/low tide cycle
Called a diurnal tide
Examples:
Lake Charles, LA
Gulfport, MS
Gulf Shores, AL
Pensacola, FL
Two tides? Four tides?: Two tides? Four tides? Number of tides per day related to…
Shape of the coastline
Sea floor elevation
Other places have two high/low tide cycles
Called a semi-diurnal tide
Examples:
Galveston, TX
Apalachicola, FL
Largest Tidal Range in the World: Largest Tidal Range in the World Bay of Fundy!
Where is the Bay of Fundy?: Where is the Bay of Fundy?
The Knights Who Say “Neap”: The Knights Who Say “Neap” Occur when the pull of the moon and sun partially cancel each other
RESULT:
Very little change between high and low tides
Springing Onward…: Springing Onward… Occurs when the pull of the sun and moon act together
RESULT:
Greater than normal tidal range experienced
About the Cost of Your Food…: About the Cost of Your Food… Normally…
Warm waters over Central Pacific
Cooler waters off Peruvian coast
Colder, nutrient-rich waters pulled up from western coast of South America
About the Cost of Your Food…: About the Cost of Your Food… El Nino:
Equatorial Countercurrent strengthens
Nutrient-rich water supply lessens
RESULT:
Waters warm off Peruvian Coast
About the Cost of Your Food…: About the Cost of Your Food… La Nina:
Weaker Equatorial Countercurrent
Nutrient-rich water supply increases
RESULT:
Warm waters “pile up” in the western Pacific
What Does This Mean Weatherwise?: What Does This Mean Weatherwise? For El Nino Events –
What Does This Mean Weatherwise?: What Does This Mean Weatherwise? For La Nina Events –
So???: So??? A lot of fishing takes place off the coast of Peru
Anchovy fish thrive in the nutrient-rich waters of this area
Anchovies are caught and used to make chicken feed
So???: So??? During big El Nino events:
Waters are not full as nutrients
Not as many anchovies
Cost of chicken feed increases
Therefore, the cost of chicken increases
Thank You!!!: Thank You!!! Douglas Butts
Senior Forecaster
WFO Shreveport
5655 Hollywood Ave.
Shreveport, LA 71109
318.631.3669
Slide51: CREDITS:
Texas A&M University Oceanography Department
www-ocean.tamu.edu
NWS Southern Region Jetstream Program
www.srh.noaa.gov/srh/jetstream CREDITS:
Texas A&M University Oceanography Department
www-ocean.tamu.edu
NWS Southern Region Jetstream Program
www.srh.noaa.gov/srh/jetstream