# Presentation: 562015

## The Oceans

*A Presentation on Atmosphere-Ocean Interaction*

**National Weather Service**

***Shreveport, LA***

**Presented by:**

## Why study major bodies of water?

- Water covers nearly 3⁄4 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

**Notes:**
Water covers 71% of the earth’s surface and contains 97% of the earth’s water.  60% of the world’s population live within 60 miles of the coast.  This means that a significant amount of the earth’s population uses the oceans and other large bodies of water for recreational (e.g., swimming, fishing) and commercial (e.g., transportation, fishing, etc.) purposes.  El Nino/ENSO are long-term climate impacts which are affected by area oceans.  The transport of low-level moisture across the United States, especially from the Gulf of Mexico and Atlantic play major roles in the day-to-day weather and aid in thunderstorm development.  Of course, we can’t forget food.  As we will see, El Nino/ENSO play roles in the cost of chicken at KFC.

## The “Basics”

- There are ***FOUR*** oceans

***ATLANTIC***
***PACIFIC***
***INDIAN***
***SOUTHERN***

**Notes:**
Ask the question, “WHO CAN NAME ALL FOUR OCEANS?”
Honestly, there is some debate on this point.  Just about everyone agrees there are definitely THREE oceans – the Atlantic, Pacific, and Indian.  Most people agree there is a fourth ocean – the Southern Ocean (which was created in 2000).  However, most oceanographers argue the Arctic Ocean isn’t really an ocean since it’s almost completely enclosed by land.  After seeing international agreement on the Southern Ocean, I grudgingly added it to the presentation.  After all, it’s nothing more than an extension of the other three.  That, then leads to the rather esoteric topic of whether or not there is just one ocean.  That’s another powerpoint, though.

## Around the World in 4 Slides...

**Notes:**
Begin with the Atlantic.  Ask the audience to POINT OUT SOME THINGS THEY NOTICE ABOUT THE ATLANTIC.
The Atlantic Ocean encompasses pretty much everything on the map north of 60° South latitude.  The Mediterranean, Caribbean, and Arctic Seas, as well as the Gulf of Mexico are all included in the Atlantic basin.  It also provides some of the earth’s most heavily trafficked routes.

## Around the World in 4 Slides...

**Around the World in 4 Slides...**

**Notes:**
Now for the Pacific.  Ask the audience to POINT OUT SOME THINGS THEY NOTICE ABOUT THE PACIFIC.
Similar to the Atlantic, the Pacific Ocean encompasses pretty much everything on the map north of 60° South latitude.  The Bering and Japan Seas, as well as the Gulf of Alaska are all included in the Pacific Basin. Interesting side note here – the Pacific Ocean covers 28% of the global surface and contributes more than half to the world’s annual fish catch.  Pacific Ocean also has the most coastline of the four oceans.

Ask the audience – WHAT IS THE SIGNIFICANCE OF THE MARIANA TRENCH?  
The Mariana Trench is the deepest part of the earth’s oceans.  The deepest point is called Challenger Deep, named after the British exploration vessel HMS Challenger II.  It has a depth of 10,911m or 35,798ft.  It is further below sea level than Mount Everest is above it.  The U.S. Navy bathyscaphe Trieste reached the bottom at 1:06 PM on January 23, 1960.  What’s at the bottom? Reportedly, flounder about a foot long and shrimp.  At the bottom of the trench, the water exerts a pressure of 1086 bar or almost 16,000 psi.  That’s more than 1,000 times the standard atmospheric pressure at sea level (1013.25mb).

## Around the World in 4 Slides...

**Notes:**
Further west still with the Indian.  Ask the audience to POINT OUT SOME THINGS THEY NOTICE ABOUT THE INDIAN OCEAN.
The Indian Ocean encompasses areas between the Indian subcontinent/Asia and 60° South latitude.  The Arabian and Red Seas, as well as the Persian Gulf are all included in the Indian Ocean basin. Interesting side notes here – Estimated 40% of the world’s offshore oil production comes from the Indian Ocean.

## Around the World in 4 Slides...

*“**Defined” in 2000*

**Notes:**
Finish with the Southern Ocean.  Ask the audience to POINT OUT SOME THINGS THEY NOTICE ABOUT THE SOUTHERN OCEAN.
The Southern Ocean encompasses anything poleward of South latitude and is made of “parts” of the Atlantic, Pacific, and Indian Oceans.  It is also the newest ocean, as it was defined in 2000.

## 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*

**Notes:**
There’s no real hard or fast definition for this.  This definition is the most widely accepted definition provided by oceanographers.  On the map of the Mediterranean Sea, be sure to point out the Black Sea which borders Turkey.  

## Bragging Rights...

**Which ocean is the biggest?**

| OCEAN | SURFACE AREA [km2] | OF ALL OCEANS... |
| --- | --- | --- |
| Atlantic | 90,818,000 | 27.1% |
| Indian | 68,556,000 | 20.4% |
| Pacific | 155,557,000 | 46.4% |
| Southern | 20,327,000 | 6.1% |

**Notes:**
Ask the audience, “WHICH OCEAN DO YOU THINK IS THE BIGGEST?”
Note here – The Atlantic basin encompasses the Arctic Sea.  Some people consider this to be the fifth ocean.  If these two are separated...
Atlantic: 29,637,000/22.8%
Arctic: 5,427,000/4.2%

## Bragging Rights...

**Which ocean has the most coastline?**

| OCEAN | COASTLINE LENGTH [km] |
| --- | --- |
| Atlantic | 111,866 |
| Indian | 66,526 |
| Pacific | 135,663 |
| Southern | 17,968 |

**Notes:**
It might also be interesting to point out here that coastal areas around the Pacific are known as the “Ring of Fire.”  This is due to the plate tectonic action that takes place.

## Water is Water...or is it?!

_***FRESHWATER***_
**Rivers**
**Streams**
**Lakes**

_***SALTWATER***_
**Oceans**
**Gulfs**
**Seas**

- But wait, there's more!

**Notes:**
Some near coastal inland bodies of water may have a mixture of salt and fresh water.  This type of water is called “brackish.”

## Water is Water...or is it?!

_***QUESTION:***_
**Is saltwater the same everywhere?**
_***ANSWER:***_
**Nope.**
**In general, the Atlantic Ocean is the “saltiest.”**

**Notes:**
The “saltiness” or salinity of the water is measured as a ratio of grams of salt per liter of water.

## 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...

**H**

**H**

**H**

**H**

**H**

**L**

**L**

**L**

**Notes:**
The first H that flies in is over the Persian Gulf/Red Sea area.  With 40% salinity, this is the saltiest water on earth.  Why?  Primarily because there’s no real “outlet” for fresh and ocean water to be exchanged.  This is also a location of very high evaporation rates.  When the water is evaporated, the salt is left behind.  The “freshest” water is near the Arctic Circle due to melting ice.  Other relative maxes and mins are shown.  Note that there are mins near the equator.  Persistent thunderstorm activity in this region keeps the water a little better fresher here.

## 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

**Notes:**
The Dead Sea is actually a large lake, 47 miles long and about 11 miles wide.  The intense evaporation leaves behind the salt, which precipitates onto the sea floor. In fact, the surface of the lake is the least salty.  Other trivia facts – the surface of the Dead Sea is over 1300 ft. below sea level, with the very bottom part of the sea is over 2300 ft. below sea level.  And BTW, it’s kind of obvious why the Dead Sea was called the Dead Sea.  Christian Monks found no life in the body of water because of the high salinity.

## So??

- The increased
- density means
- just about *anything*
- will float!

- We can see this through the use of eggs!

**Notes:**
The lady in this picture may look like she’s floating on a pool raft, but she’s not.  She’s actually floating on the water with very little effort.  In fact, several websites say that swimming takes much more effort than floating.  At this point an experiment could be conducted using a couple of fresh eggs and some mason jars of salt water.

## We’re Goin’ Down, Down, Down...

**Just like the atmosphere, the ocean has layers!**

**Notes:**
Point out the similarities between the atmosphere and ocean.  Just like the atmosphere, each ocean layer has unique characteristics of pressure, types of life, temperature, etc.  The next few slides will cover each layer of the ocean.

## The Epipelagic Zone

- “Sunlight Zone”
- Most solar heating
- Lots of temperature change
- Surface to 200m
- Influenced by wind

**Notes:**
The top layer of the ocean is the epipelagic zone, which receives the most heating from the sun.  This results in a wide variation of temperature in a relatively short distance.  This is also where the wind has the most influence, and results in mixing and heat distribution.

## Bridge Over Troubled Waters...

- A transition layer
- Temperature decreases rapidly
- Relevance to you?
- Higher bass concentrations (oxygen is just right)

**Notes:**
The thermocline is the transition layer between the mixed waters of the Epipelagic Zone and the deeper waters below.  Where, relatively speaking, the Epipelagic and Mesopelagic Zones are homogeneous temperature-wise, the thermocline bridges the gap, so-to-speak.

## The Mesopelagic Zone

- “Twilight Zone”
- Most temperature change near top of layer
- Between 200 and 1000m
- Animal characteristics begin to change

**Notes:**
Why is it called the “twilight zone”? Because the sunlight is very faint.  How do animal characteristics begin to change? You start seeing bioluminescence.  Eyes are generally larger and directed upward, probably to see the outline of animals above.

## 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.

**Notes:**
The animals that live in this region of the ocean are bioluminescent.  Regarding the pressure, remember that the pressure at the earth’s surface is 14.7 p.s.i.  

## The Abyssopelagic Zone

- “The Abyss”
- Greek word meaning “no bottom”
- Between 4000 and 6000m
- Water temperature near freezing

**Notes:**
Interesting thought – Greeks through there was no bottom.  Hence the name that was given.

## 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!**

**Notes:**
The Hadalpelagic Zone encompasses everything below about 6,000m.  Reiterate the fact that the Mariana Trench is the deepest trench in the world.  Might even want to ask the question – “WHAT IS THE NAME OF THE DEEPEST PART OF THE MARIANA TRENCH?” (Ans. Challenger Deep, 10,911 meters)  Life still exists, although it’s in the form of plankton.

## Our Mr. Sun

- “Driving Force”
- Solar radiation affects the ocean differently
- More on this later
- Ultimate cause of wind

**Notes:**
Incoming solar radiation (or insolation) is the ultimate cause of the weather on the earth.  As solar insolation hits the earth’s surface, it heats the atmosphere during the day and cools at night.  When it heats the ocean, pretty much the same thing happens, only more slowly.  As such, once the epipelagic zone is warmed, it stays warmer longer.  These temperature differences cause wind.  But more on this later, though.

## 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

**Notes:**
There are 2 types of ocean currents.  The first, wind-driven currents, occurs in the epipelagic zone.  Meanwhile, deeper currents bring very cold water further “up” in the ocean.  Here, though, we’re going to focus on wind-driven currents.  These ccean currents are responsible for 40% of the global heat transport.  As an example of the long-term climate impacts, the overall climate of Norway and the British Isles is about 10°C warmer than other cities at the same latitude due to the effects of the Gulf Stream.

## 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

**Notes:**
Admittedly, this is a confusing diagram.  Moral of the story– as the oceans near the equator heat more rapidly, it sets up an imbalance in temperature, where cold air sinking from the poles replaces the rising warm air near the equator.  As the earth rotates, this sets up nearly permanent pressure areas and associated wind fields.  It’s this constant push of wind on the water that results in the development of wind-driven ocean currents.

## Ocean Currents – The Big Picture

**Notes:**
Here, we proudly present the big ‘ol map of ocean currents. The important ones to point out – Peruvian and California Currents, as well as the Gulf Stream.

## The Gulf Stream

## 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

**Notes:**
This slide describes the development of the seabreeze.  Basically, since the beach heats up faster than the ocean during the day, the air will start to rise here.  To replace the rising air, slightly cooler, more dense air has to move onshore from the ocean to replace the rising air.  This results in a breeze blowing from the ocean, and, if conditions are right, possible thunderstorm development.

## 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

**Notes:**
This slide describes the development of the landbreeze.  After dark, the ocean still has more heat than the land.  As such, the air will continue rising offshore at night.  Cooler, more dense air from the beach (since it cools down more quickly) will replace the rising air offshore. This results in a breeze blowing from the land, and, if conditions are right, possible nocturnal thunderstorm development offshore.

## 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

**Notes:**
Regarding wave size – The wind has to be blowing faster than the tops of the waves.  That meets the speed criteria.  The longer that strong wind has been blowing, the better chance it has to generate large waves.  The distance criteria is also known as the “fetch”.  Basically, this is the uninterrupted distance over which the wind blows without a big change in direction.  Estimating the wind speed using this method is known as the Beaufort Scale.

## 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

**Where are the largest ranges from high to low tide in the world?**

## 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

**Notes:**
True, the sun’s gravitational pull on the earth is greater.  In fact, it’s 178 times greater than that of the moon.  But the determining thing is distance.  Simply put, the earth is a lot closer to the moon than the sun.  Because of that reason, the moon has twice the tidal pull on the earth when compared to that of the sun.  Most of the time, we’ll see a “bulge” of water mainly in line with the moon...one on the side of the moon and the other generally in the same spot on the other side of the earth.  I mentioned that mariners have known for a long time that tides were related to the moon.  How long you say?  About 4,000 years.

## Battle of the Bulge

- Famous dead people who have studied tidal motion:
- Galileo
- Descartes
- Newton
- Laplace
- Lord Kelvin
- Kepler

**Notes:**
Point out that these are some of the greatest scientific minds of our time.

## POP QUIZ

**Where are the largest ranges from high to low tide in the world?**

- Have an answer yet?

**HINT: **It’s in North America

## 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?

- 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

**Notes:**
Remember the “bulge” in water I mentioned earlier?  In general, when we see tides, we are seeing the result of the earth rotating under the “bulge”.  Using this principle, most places should see a high or low tide every 6 hours or so.  However, like I said before, this is dependent upon the coastline’s shape and the elevation of the sea floor.  One thing to note: when the moon is closest to earth in its orbit, the tidal influence is obviously greater.  

## Largest Tidal Range in the World

**Bay of Fundy!**

**Notes:**
Tidal ranges at the Bay of Fundy can be as much as 15 meters in some spots.

## Where is the Bay of Fundy?

## 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

**Notes:**
The moon rotates around the earth once every 28 days (or so).  About twice a month (every 14 days), the moon and the sun will be at right angles with respect to the earth.  When this occurs, the tidal influence of the moon and sun will partially cancel each other out, resulting in little difference between high and low tides.  For example, in places that only see one high/low tide cycle a day, you’ll see 2 or more cycles when tides are neap.

## Springing Onward...

- Occurs when the pull of the sun and moon act together
- RESULT:
- Greater than normal tidal range experienced

**Notes:**
A spring tide is basically the opposite of a neap tide.  It occurs when the moon and sun are in line with each other, which maximizes the gravitational effects.

## 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

**Notes:**
In a normal year, the Peruvian Current brings colder waters from the Southern Ocean northward along the coast of Peru.  These waters are filled with lots of nutrients, which feed the fish living in the southern Pacific Ocean.  Note also that the Equatorial Countercurrent tries to bring warmer water eastward toward the coast of South America.  Before leaving this slide, ask the audience, “WHAT WOULD HAPPEN IF THE EQUATORIAL COUNTERCURRENT WAS TO STRENGTHEN?”

## About the Cost of Your Food...

- El Nino:
- Equatorial Countercurrent strengthens
- Nutrient-rich water supply lessens
- RESULT:
- Waters warm off Peruvian Coast

**Notes:**
Regardless of whether or not you hear about it, El Nino occurs each year.  It is actually named for the Christ Child, since it takes place toward the end of December.  Usually, we only hear about the bigger El Nino events.  When these events occur, there can be a major shift of the warm waters with several effects, especially in regard to the track of major storm systems.

## 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

**Notes:**
During a La Nina year, the Equatorial Countercurrent relaxes, allowing an “abundance” of cooler water to return to the region.  When this takes place, the warmer waters will be pushed (so-to-speak) into the western Pacific.  This is basically the opposite of El Nino conditions.  Like El Nino, though, it can have major effects on the path major storm systems take.

## What Does This Mean Weatherwise?

**For El Nino Events – **

**Notes:**
In large El Nino events, leads to a more active jet stream in our part of the country.  This means a large trough of low pressure appears to generally be over the eastern half of the country during the winter, which spells cooler and wetter conditions.

## What Does This Mean Weatherwise?

**For La Nina Events – **

**Notes:**
In large La Nina events, increased ridging tends to be seen over our part of the country during the winter.

## 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???

**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!!!

**Douglas Butts**
**Senior Forecaster**
**WFO Shreveport**
**5655 Hollywood Ave.**
**Shreveport, LA 71109**
**318.631.3669**

## 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**