Ocean and the Ocean and the AtmosphereAtmosphere

Notes for Ocean PlanetNotes for Ocean Planet

WnekWnek

Layers of the atmosphereLayers of the atmosphere

The role of the atmosphereThe role of the atmosphere

The atmosphere influences the The atmosphere influences the ocean, especially through wind-ocean, especially through wind-driven and density driven circulationdriven and density driven circulation

Wind-driven circulation can cause a Wind-driven circulation can cause a deflection of water off continents deflection of water off continents

The wind-driven pattern can create The wind-driven pattern can create coastal upwelling and downwelling coastal upwelling and downwelling patterns (discussed later)patterns (discussed later)

Earth’s RotationEarth’s Rotation

Coriolis Effect Coriolis Effect Ekman SpiralEkman Spiral The Motion of the The Motion of the

earth can be up to earth can be up to 45 degrees to the 45 degrees to the right of the wind right of the wind direction in the direction in the northern northern hemisphere and left hemisphere and left in the southern in the southern hemispherehemisphere

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Upwelling Upwelling

Movement of water away from land Movement of water away from land (coasts) where it is replaced by (coasts) where it is replaced by colder water (nutrient rich) from colder water (nutrient rich) from deeper areasdeeper areas

The movement of water away from The movement of water away from the coast is called “divergence”the coast is called “divergence”

In the northern hemisphere on the In the northern hemisphere on the east coast of continents a southerly east coast of continents a southerly wind causes upwelling…wind causes upwelling…

Courtesy of NOAA 2004

Upwelling SchematicUpwelling Schematic

http://oceanservice.noaa.gov/education/kits/currents/03coastal4.html

Courtesy of NOAA 2004

The role of the windThe role of the wind Unequal heating of the atmosphere Unequal heating of the atmosphere

by the land and ocean surfacesby the land and ocean surfaces Friction between the moving air and Friction between the moving air and

the ocean surface create surface the ocean surface create surface currentscurrents

Negating the rotation of the earth, Negating the rotation of the earth, the wind would cause surface the wind would cause surface currents to move, thus layers move currents to move, thus layers move below it causing a net movementbelow it causing a net movement

Pacific Decadal Oscillation considered a climate index (Mantua et al. 1997; NOAA 2011)

Increase in carbon dioxide levels between 1960 and 1990. Image from Purves et al., Increase in carbon dioxide levels between 1960 and 1990. Image from Purves et al., Life: The Science of BiologyLife: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and , 4th Edition, by Sinauer Associates (www.sinauer.com) and

WH Freeman (www.whfreeman.com).WH Freeman (www.whfreeman.com).

It is difficult to believe that a chemically It is difficult to believe that a chemically active gas such as carbon dioxide can active gas such as carbon dioxide can remain unaffected by burial in ice for as remain unaffected by burial in ice for as long as 160,000 years. There are long as 160,000 years. There are questions whether the carbon dioxide can questions whether the carbon dioxide can diffuse through the snow, react with dust diffuse through the snow, react with dust particles, or form clathrate compounds particles, or form clathrate compounds under pressure The technique of drilling, under pressure The technique of drilling, removal and preservation of the ice core is removal and preservation of the ice core is very difficult, and there are many things very difficult, and there are many things that can go wrong (Jaworski, 1996, 1997). that can go wrong (Jaworski, 1996, 1997).

Are Ice Cores Accurate?Are Ice Cores Accurate?

The period since 1972, when the The period since 1972, when the increase has been linear despite an increase has been linear despite an increase of over 45% in emissions, increase of over 45% in emissions, suggests that there are new carbon suggests that there are new carbon sinks being established in the ocean sinks being established in the ocean and in the terrestrial biosphere to and in the terrestrial biosphere to absorb the increases (Gray, 1998). absorb the increases (Gray, 1998).

FindingsFindings

Global mean sea level has been Global mean sea level has been rising at an average rate of 1 to 2 rising at an average rate of 1 to 2 mm/year over the past 100 years, mm/year over the past 100 years, which is significantly larger than the which is significantly larger than the rate averaged over the last several rate averaged over the last several thousand years. Projected increase thousand years. Projected increase from 1990-2100 is anywhere from from 1990-2100 is anywhere from 0.09-0.88 meters (depending on the 0.09-0.88 meters (depending on the severity of the warming) severity of the warming)

Sea Level RiseSea Level Rise

Ocean Currents?Ocean Currents?

Illustration by Jack Cook, Woods Hole Oceanographic Institution

This is now being reconsidered in terms of the rate of slowing

Rising carbon dioxide indicate upper-Rising carbon dioxide indicate upper-ocean stratificationocean stratification

Stability will increase & mixing will Stability will increase & mixing will decrease the next 50 yearsdecrease the next 50 years

Net primary productivity (NPP) of Net primary productivity (NPP) of microplankton will increase and microplankton will increase and megaplankton will decrease (Barber megaplankton will decrease (Barber 2007) 2007)

Coupled ocean-atmospheric modelsCoupled ocean-atmospheric models

Precipitation is also expected to Precipitation is also expected to increase over the 21st century, increase over the 21st century, particularly at northern mid-high particularly at northern mid-high latitudes, though the trends may be latitudes, though the trends may be more variable in the tropics.more variable in the tropics.

Snow extent and sea-ice are also projected to decrease further in the northern hemisphere, and glaciers and ice-caps are expected to continue to retreat.

The Future The Future

Weather and the OceanWeather and the Ocean

Pressure GradientsPressure GradientsAir is constantly moving to seek an equilibrium between areas of more air molecules (higher pressure) and those with less (lower pressure).

Wind is nothing more than the movement of air molecules from one place to the next. The direction and speed of the wind represents the balance between three basic forces acting on it: the pressure gradient, the Coriolis force, and surface friction. 

Pressures are trying to stay in balance. Pressures are reported in Isobars

IsobarsIsobars

What is a jet stream?What is a jet stream? It is an area with significant pressure It is an area with significant pressure

differences within a 9 km band differences within a 9 km band

It generally moves from west to east It generally moves from west to east and is more substantial in from 20,000 and is more substantial in from 20,000 feet or higherfeet or higher

Can move in speeds greater than 200 Can move in speeds greater than 200 mphmph

Can dip down in the winter as a result Can dip down in the winter as a result of sinking cold air from the northof sinking cold air from the north

NOAA.gov

Tropical SystemsTropical Systems

Defined as low pressure systems that have a counterclockwise rotation in the northern hemisphere & the opposite in the southern hemisphere

The opposite rotation in each hemisphere is due to the Coriolis Effect

They are all CYCLONES; however they are called HURRICANES in the western hemisphere and strong storms are TYPHOONS in the eastern hemisphere

Formed by storms, Intertropical Convergent Zone areas

Tropical CyclonesFor a cyclone to form, the ocean waters need to be warm, at least 26°C. Above the warm ocean, water evaporates and form clouds. If there is low air pressure where the clouds are formed, it pulls them in and they begin to rotate.

If a storm achieves wind speeds of 38 miles (61 kilometers) an hour, it becomes known as a tropical depression.

Hurricanes spin around a low-pressure center known as the “eye.” Sinking air makes this 20- to 30-mile-wide (32- to 48-kilometer-wide) area notoriously calm. But the eye is surrounded by a circular “eye wall” that hosts the storm’s strongest winds and rain.

http://www.cyclonerita.com/hurricane-irene.html

NASA.gov

Scale to determine the strength of tropical cyclones1 knot = 1.15 miles/hour

Storm DesignationsStorm Designations

The Saffir-Simpson Hurricane Wind Scale is a 1 to 5 categorization based on the hurricane's intensity at the indicated time.

Where do tropical cyclones come from and when?

Most hurricanes begin in the Atlantic as a result of tropical waves that move westward off the African coast.

Official Hurricane season is June 1 – November 30 each year.

Many early and late Atlantic Ocean Hurricanes originate in the Gulf of Mexico or Caribbean

Intertropical Convergence ZoneIntertropical Convergence Zone

Intertropical Convergence ZoneIntertropical Convergence Zone

Tropical Activity as of September 4, 2011 (Weather Underground)

Weather underground. com

Hurricane Irene (NASA 2011)

Hurricane Sandy 2012

Problems Associated with Tropical Cyclones

Winds Storm SurgeFlooding

Hurricane Irene Storm Surge at New Bourne, NC

Storm Surge Can Devastate Marinas

Storm Surge in Bayside Long Island from Hurricane Irene

Pier at Atlantic Beach, NC

Ranking Storm ID Storm Name Origin DateMinimum Central Pressure (in mb.)

1 1347 WILMA 2005-10-15 882

2 1122 GILBERT 1988-09-08 888

3 615 UNNAMED 1935-08-29 892

4 1342 RITA 2005-09-18 897

5 1045 ALLEN 1980-07-31 899

6 1336 KATRINA 2005-08-23 902

7 934 CAMILLE 1969-08-14 905

8 1234 MITCH 1998-10-22 905

9 1383 DEAN 2007-08-13 907

10 1314 IVAN 2004-09-02 910

11 815 JANET 1955-09-21 914

12 1298 ISABEL 2003-09-06 915

13 1134 HUGO 1989-09-10 918

14 1196 OPAL 1995-09-27 919

15 1097 GLORIA 1985-09-16 920

16 870 HATTIE 1961-10-27 920

17 1241 FLOYD 1999-09-07 921

18 1161 ANDREW 1992-08-16 922

19 917 BEULAH 1967-09-05 923

20 14 UNNAMED 1853-08-30 924

Hurricanes: The Most Powerful on Record (Lowest Pressures)

Sandy was 940 mb at landfall, which is lowest north of NC ever!

Nor’eastersNor’easters

Nor’easterNor’easter

These strong areas of low pressure often form either in the Gulf of Mexico or off the East Coast in the Atlantic Ocean. The low will then either move up the East Coast into New England and the Atlantic provinces of Canada or out to sea.

Detailed studies taken from satellite imagery and other readings suggest that some low pressure systems associated with nor'easters may develop tropical storm characteristics such as an eye in the center of the low.

El Niños are not caused by global El Niños are not caused by global warming. warming.

However, it has been hypothesized However, it has been hypothesized that warmer global sea surface that warmer global sea surface temperatures can enhance the El temperatures can enhance the El Niño phenomenon, and it is also true Niño phenomenon, and it is also true that El Niños have been more that El Niños have been more frequent and intense in recent frequent and intense in recent decades. decades.

El NinoEl Nino

La Nina 1998-1999

dnr.sc.gov

El Nino and its impacts on the El Nino and its impacts on the Leatherback Sea TurtleLeatherback Sea Turtle

in Costa Ricain Costa Rica

All of the pictures and graphics were provided by Dr. James Spotila, Drexel University and the Leatherback Trust

Leatherback

Jelly-vore

The turtle all the other biologists wish they could study

1719 turtles have been tagged in 11 years1719 turtles have been tagged in 11 years 448 have returned to nest again448 have returned to nest again

Annual mortality rates 22%Annual mortality rates 22%

Results- counting turtles

22%!!

Leatherbacks in the PacificLeatherbacks in the Pacific

1980- 91,000 adult females1980- 91,000 adult females 1995- 6,500 adult females1995- 6,500 adult females 2000- 3,490 adult females2000- 3,490 adult females

East Pacific- 1995- 4638East Pacific- 1995- 4638

2000- 16902000- 1690

2006- 8002006- 800

Exponential DeclineExponential Decline

Parque Nacional Marino Las Baulas, Costa Rica

1504 1474

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Climatic variables may play a major role in influencing return interval and

apparent population size

Beach Profile for Marker #1

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Normal Dune elevation has a berm but with development the berm is destroyed

ThreatsFishingLonglinesGill NetsShrimp Nets

PoachingEggsAdults

Loss of Nesting Beaches

No nesting beaches = no turtles

••Longlining for swordfish and tuna is one of the most Longlining for swordfish and tuna is one of the most significant threats to sea turtlessignificant threats to sea turtlesLonglines stretch as much as 60 miles and have Longlines stretch as much as 60 miles and have thousands of baited hooksthousands of baited hooks~1.4 billion longline hooks in the oceans each year~1.4 billion longline hooks in the oceans each year

Graphic: Sea Turtle Restoration Project

The Great BP Oil SpillThe Great BP Oil Spill

The large strands of sargassum seaweed atop The large strands of sargassum seaweed atop the ocean are normally noisy with birds and thick the ocean are normally noisy with birds and thick with crustaceans, small fish and sea turtles. But with crustaceans, small fish and sea turtles. But now this is a silent panorama, heavy with the now this is a silent panorama, heavy with the smell of oil.smell of oil.

There are no birds. The seaweed is soaked in rust-colored crude and chemical dispersant. It is devoid of life except for the occasional juvenile sea turtle, speckled with oil and clinging to the only habitat it knows. Thick ribbons of oil spread out through the sea like the strips in egg flower soup, gorgeous and deadly.

Loss of 10 years of sea turtle Loss of 10 years of sea turtle conservation- Effects for a generationconservation- Effects for a generation

Boiling the turtles alive!Boiling the turtles alive!

Barber, R.T. 2007. Barber, R.T. 2007. Picoplankton do some heavy lifting. Picoplankton do some heavy lifting. Science, Science, February 9: pp. 777-778.February 9: pp. 777-778.

Etheridges, D.M., L.P. Steele, R.L. Langenfelds, R.J. Francey, J.-M Etheridges, D.M., L.P. Steele, R.L. Langenfelds, R.J. Francey, J.-M Barnola, V.I. Morgan. 1996. "Natural and anthropogenic changes Barnola, V.I. Morgan. 1996. "Natural and anthropogenic changes in atmospheric CO2 over the last 1000 years from air in Antarctic in atmospheric CO2 over the last 1000 years from air in Antarctic ice and firn" J. Geophys. Res. 101 (D2) 4115-4128ice and firn" J. Geophys. Res. 101 (D2) 4115-4128

Etheridges, D.M., L.P. Steele, R.L. Langenfelds, R.J. Francey, J.-M Etheridges, D.M., L.P. Steele, R.L. Langenfelds, R.J. Francey, J.-M Barnola, V.I. Morgan. 1996. "Natural and anthropogenic changes Barnola, V.I. Morgan. 1996. "Natural and anthropogenic changes in atmospheric CO2 over the last 1000 years from air in Antarctic in atmospheric CO2 over the last 1000 years from air in Antarctic ice and firn" J. Geophys. Res. 101 (D2) 4115-4128ice and firn" J. Geophys. Res. 101 (D2) 4115-4128

Gray, V.R., 1998. "The IPCC future projections: are they plausible" Gray, V.R., 1998. "The IPCC future projections: are they plausible" Climate Research 10 155-162Climate Research 10 155-162

http://palaeo.gly.bris.ac.uk/Palaeofiles/Permian/PALIntro.htmlhttp://palaeo.gly.bris.ac.uk/Palaeofiles/Permian/PALIntro.htmlhttp://www.ncdc.noaa.gov/oa/climate/globalwarming.html#Q11http://www.ncdc.noaa.gov/oa/climate/globalwarming.html#Q11Jaworowski, Z. 1996 "Reliability of Ice Core Records for Climatic Jaworowski, Z. 1996 "Reliability of Ice Core Records for Climatic

Projections" in "The Global Warming Debate", (John Emsley, Ed.) Projections" in "The Global Warming Debate", (John Emsley, Ed.) European Science and Environment Forum , London, 95-105.European Science and Environment Forum , London, 95-105.

Jaworowski, Z., 1997. "Ice Core Data Show No Carbon Dioxide Jaworowski, Z., 1997. "Ice Core Data Show No Carbon Dioxide Increase" 21st Century Science and Technology 10 , (1) 42-52Increase" 21st Century Science and Technology 10 , (1) 42-52

ReferencesReferences