Introduction

The ocean occupies over 70% of the earth's surface. Ocean waters are constantly in motion. The global ocean movement is a result of several factors, including interactions with the atmosphere, pressure changes, earth's spin and rotation. This circulation of the ocean waters, coupled with temperature difference, have an effect on global and regional weather. Some of the better known effects are from the equatorial Pacific area where changes in global weather patterns have been associated with El Nino/La Nina anomalies. The North Atlantic Oscillation, however, has a more direct affect on the mid-Atlantic weather. Scientist, Dr. Ming Li, explains these ocean-weather-climate interactions. Using ocean observing websites, teachers can explore ocean currents, such as the Gulf Stream, how observing systems can monitor these currents, the interaction of the atmosphere with ocean currents, and the effects of ocean currents on climate and weather. Ocean changes can affect coastal areas. In particular, storm surges (acute) and global warming of the oceans (chronic) are causing sea levels to rise. A field trip by kayak in the marshes of the Blackwater National Wildlife Refuge and a classroom activity explores the effect of global warming and sea level rise on a local area.

Activity

Globe Toss (adapted from the Lawrence Hall of Science)

Objective: To introduce the concept that the ocean comprises a significant portion of the earth's surface.

Science Overview

Topic: Global Ocean Circulation and Weather

Dr. Li presents his research on global ocean circulation and focus on the ocean/atmosphere interactions. (click here for presentation)

Dr. Ming Li Education: 1991, Ph. D., Oxford University 1983, B. Eng., Hohai University Position: Associate Professor What I do: Study the relationship between ocean currents and climate

Classroom Activities

Website Exploration: Ocean Observing Systems
L. Murray

Objective: Participants will become familiar with the ocean and how scientists observe them.

Introduction

Ocean observing systems can deliver real-time data and information about the ocean waters, including temperature, currents, wave height, salinity and other parameters scientists use to interpret the ocean conditions. Observing systems include a variety of instruments which sense these parameters, including satellites, which sense the oceans from far above, moored (stationary) buoys, which communicate information directly to land-based computers and are accessed via the internet, and roving sensors (sonars), which can travel remotely through the water and radio information to receivers.

The circulation of the oceans waters, coupled with temperature difference have an effect on global and regional weather. These ocean/atmospheric/weather interactions have been studied in the equatorial Pacific area (El Nino/La Nina Southern Oscillation, ENSO). In the mid-Atlantic, the North Atlantic Oscillation (NAO) has a more direct affect on the mid-Atlantic weather.

The ocean observatory Web sites listed below can deliver real-time data about ocean currents and circulation via the Internet. The purpose of this exercise is to acquaint the user with A) major ocean circulation patterns, B) explore the many ocean observing systems and the types of information they provide, and C) the ENSO and NAO as viewed through the eyes of observing systems.

Materials

Computers with internet connection
Website Exploration worksheet

A.   Ocean Currents of the World

Go to the below websites for detailed information on ocean circulation patterns.
http://www.windows.ucar.edu/cgi-bin/tour_def/earth/Water/ocean_currents.html
http://www.onr.navy.mil/Focus/ocean/motion/currents1.htm

(click for larger view)

National
http://www.csc.noaa.gov/coos/index.html
http://www.ndbc.noaa.gov

International
http://www.ncdc.noaa.gov/gsn/gsn

C. Ocean movement measurements using observing systems

As an introduction to ocean observing systems, explore these websites to get a "feel" for how an array of observing systems can tell us what is happening real time in the ocean and how we can predict effects of changes in ocean circulation patterns and the resulting effects on climate and weather. In Example 1 below The Equatorial Pacific ocean movements are measured by an array of buoys, which can predict events such as El Nino. Explore the following website to learn more about the ENSO and how ocean currents are measured (TAO website). Weather in the Mid-Atlantic region is primarily affected by the North Atlantic Oscillation (NAO). Visit this website to get an idea of how the NAO influences our weather (Example 2).

Example 1 http://iri.columbia.edu/climate/ENSO/	ENSO Cycle: El Niņo/La Niņa
http://www.pmel.noaa.gov/tao/index.shtml Tropical Atmosphere Ocean (TAO)
Example 2 http://www.ldeo.columbia.edu/NAO/ North Atlantic Oscillation (NAO)

Website Exploration Worksheet

A. Ocean circulation

1. What current might have an effect on the weather of the Atlantic coast of the USA?
2. What current is responsible for El Nino and La Nina events off the coast of South America?

B. Ocean observing system locations

3. What is the current water temperature in the Chesapeake Bay.
4. What is the ocean temperature off the coast of Maine at this time?

C. Ocean movement measurements using observing systems.

6. Does an El Nino event affect weather strongly in the Mid-Atlantic region?
7. What stage of the NAO causes cold dry springs in Maryland?

Surface Circulation of the North Atlantic: A Model
L. Murray and L. Spence

Introduction

The ocean interacts closely with the atmosphere. Heat from the sun, evaporative, conduction and emission forces provide energy for ocean movement, while wind and density differences provide momentum. Changes in atmospheric pressure set up wind patterns. Predominant wind patterns are among the main forces which drive ocean circulation. The shape of the coastline, bathymetry of the ocean cause changes in direction (meanders) and spin-offs (gyres) from the main current. These gyres are visible in maps of sea surface temperatures of the Gulf Stream in the North Atlantic (http://fermi.jhuapl.edu/avhrr/gs/averages/). In this activity, students will explore how wind forces water movement and how land features can change this movement.

Objectives:
1. Students should be able to explain the forces which produce the circulation patterns in the Gulf Stream.
2. Students should be able to predict current patterns or eddy development with variances in bathymetry.

Materials:
Heavy duty stainless steel baking tray (10 x 16)
Modeling clay
Laminated satellite images of the Gulf Stream
Laminated Bathymetric maps of the North Atlantic
Convection Fluid Bottles, Carolina Biological Supply Catalog #, Price, Qty. GEO8450,
Hair Dryer

Procedure:
1. In groups of 3-5, use clay to build a model of the North Atlantic. Use the bathymetric maps below and be sure to include the continental shelf, continental slope, capes, seamounts, and other seafloor features.
Maps: Bathymetry of the North Atlantic
2. Create the shoreline of the North Atlantic in your container using the clay. (no more than 1-2 inches thickness of clay on edges).
3. Pour in a diluted solution of Convection Fluid to a depth which just covers the subsurface oceanic features.
4. Set up a gentle "wind" blowing from the south to start a current. Make observations on the current patterns that develop.
5. Change wind direction and speed and observe any changes in the current patterns.
6. Illustrate your notes on the observations, especially the patterns affected by the shoreline or around surface features (e.g. Cape Hatters).
7. When finished, return the Convection Fluid to the container. Remove clay from container and roll into ball.

Bathymetry of the North Atlantic

http://oceancurrents.rsmas.miami.edu/atlantic/img_topo2/gulf-stream2.jpg

Surface Circulation of the North Atlantic Worksheet

1. Did the shelf, slope or capes affect the surface current? Describe.
2. Do you think the Gulf Stream might have a greater affect on weather of the southeast vs. the northeast of the USA? Explain.
3. What other factors besides wind might affect the Gulf Stream current?

Gulf Stream Voyage: Locate the Gulf Stream with Real-time Data
L. Hotaling

http://www.k12science.org/curriculum/gulfstream/index.shtml

Objective: Students will be able to use real time data to locate the Gulf Stream

Background:

The use of satellite imagery is one of the most accurate ways to locate the Gulf Stream. The National Oceanic and Atmospheric Administration (NOAA) operates a Polar Orbiting Environmental Satellite (POES) with an Advanced Very High Resolution Radiometer (AVHRR) sensor. This sensor measures the amount of thermal infrared radiation given off by the surface of the ocean. Because the amount of thermal infrared radiation given off by an object is related to its temperature, scientists are able to calculate the temperature of the sea surface. The radiation data is color-coded to produce an image of the ocean. This satellite imagery makes it easy to locate the warm current of the Gulf Stream in the Atlantic by comparing color differences to a color/temperature scale.

Sea surface height, measured by the TOPEX/Poseidon and ERS-2 satellites is another indicator of the Gulf Stream location. The Radar Altimeter on ERS-2 sends radar signals to the Earth and ocean surface and then collects the return signal. That information is processed to reveal ocean wave height, wind speed over the ocean, surface backscatter and the satellite's altitude. This data provides the capability to monitor the global ocean circulation and regional current systems. The satellite systems offer daily global coverage. Other means of measuring sea surface temperature such as buoys (drifting and moored) are used to maintain accuracy of the satellite data.

Oceanographers use the images to visualize the Gulf Stream, its width, the number of rings and meanders, etc. Constant monitoring is necessary because the Gulf Stream is not a stable current, it meanders North and South. Sometimes these meanders are small, taking the form of waves that appear to break backward relative to the northeasterly flow of the current. In some instances, the meanders become so large that a pocket of warm water is pinched off and separated from the stream into the cooler shelf water. These are called warm core rings. The warm core rings rotate clockwise for several days, eventually drifting west to southwest until they interact with the shelf or the Gulf Stream. Most warm core rings are reabsorbed into the stream after wandering for one to three months. The effects of warm core rings were observed by early oceanographers, but the true extent was not well understood until the availability of satellite imagery. It is also interesting to note that just as meanders to the North can pinch off a warm core ring, meanders to the South can pinch off a cold core ring. These cold core rings are often less visible in the satellite imagery because of the warmer water lying above, but they can still be seen by the trained eye. (Northern Gulf Stream Image June 11, 1997) @ http:/fermi.jhuapl.edu/avhrr/gs/averages/

In the following activity, pairs of students will obtain real-time data about the Gulf Stream posted by buoys, ships and satellites and compare their findings.

Materials
For each group, copies of the tracking chart (Full Basin, Western Atlantic) For each student, copies of the Blank Gulf Stream Map Computers with Internet access Colored pencils Student Worksheets

Procedure
Gulf Stream Voyage lesson can be found at: http://www.k12science.org/curriculum/gulfstream/teachercurrentnow.shtml Create working groups of six students. Break each group of six into pairs. At the bottom of this lesson under procedure you will find a section on buoys, ships, and satellites where you may proceed with the instructions below.

Pair 1: Buoys
Have the students obtain the most recent data from the buoys listed on the Web site. They should then record the following information on the Pair 1 Student Worksheet: Latitude and Longitude, Time and Date, Air Temperature (ATMP), Water Temperature (WTMP). Scroll down the page to the previous 24 observations. Have students plot the location of the six buoys on the chart and answer the one question under the data table.

Pair 2: Ships
First, have the students obtain the most recent ship data by clicking on the ships in the North Atlantic as listed on the Web site. The symbols on the chart represent the ships and buoys currently logging data in the Northern Atlantic. The red symbols are buoys and the blue symbols represent ships. Notice the series of letters and numbers under the blue ship symbols. These are the "Ship IDs". No two sets of letters and numbers are the same. Have students locate at least two ships in the vicinity of the buoys used above and write down the exact "Ship ID" on the Pair 2 Student Worksheet.

Next, have the students click on the Ships database link. Enter the ship's ID into the white box. Click Search. Students should look through the data that the ship has recently transmitted, most ships transmit data every 6 hours. Record the water temperature. Record the locations of the ships on the chart and answer the 2 questions under the data table.

Pair 3: Satellites
Give your students the most recent satellite image of the Gulf Stream and have them answer the questions under satellite information on the Pair 3 Student Worksheet. Students will use colored pencils to sketch the approximate current location of the Gulf Stream on the chart. Students can use the latitude and longitude points to guide placement of the current.

Regroup
After each pair of students has collected their respective data and answered their questions, have the students regroup into their group of six. Have the students compare their data and answer the questions under "when you regroup with your other group members" on the worksheets.

Have students compare the ocean water temperature data from the satellite image with the temperatures collected from the ships and buoys.

Science Overview

Topic: Sea Level Rise, Acute and Chronic

Dr. Murray presents causes of short term sea level rise (acute) and long term sea level rise (chronic) (click here for presentation)

Dr. Laura Murray Education AA, Mississippi Junior College, Perkinston, Mississippi, 1969 BS (Marine Sciences), University of West Florida, Pensacola, Florida, 1971 MST (Biology/ Education), University of West Florida, Pensacola, Florida 1973 PhD (Wetlands Ecology), College of William and Mary, Virginia Institute of Marine Science, Gloucester Point, Virginia, 1983 Position: Research Associate Professor What I do: Study the restoration ecology of seagrasses and bring science to education

Field trip

Sea Level Rise: A case study of Blackwater NWR

The Blackwater National Wildlife Refuge includes almost 27,000 acres, composed mainly of rich tidal marshes characterized by fluctuating water levels and varying salinity (http://blackwater.fws.gov/). Blackwater NWR has been described as the Everglades of the Mid-Atlantic region, with extensive brackish marshes studded with pine islands. The Blackwater River, a tidal tributary to the Chesapeake Bay, flows through the Refuge. This field trip takes you through the heart of Blackwater where you will see bald eagles, various wading birds, and experience the changing landscape of a sinking wetland. Check tides at Bishopshead before field trip (www.tidesonline.nos.noaa.gov).

Classroom Activity

Sea Level Rise and Storm Surge
L. Murray and L. Spense

Focus Question: What effect will rising water have on the coast?

Objectives:
1. Students should be able to explain what areas of the coast line will be flooded in a given number of years.
2. Students should be able to predict flooding from storm surges.

Background
Sea Level is the sea height relative to a benchmark on land. Sea level rise is an increase in sea height over a period of time such that fluctuations due to tides and waves are factored over time, e.g. months to years. Over the past decades, increases in sea surface height have been attributed to increases in temperature of the ocean due to global warming. As water is heated it expands, resulting in inundation of coastal areas. Additionally the melting of the ice caps contributes to the rise in sea height.

Storm Surge is the rise in sea height due to the "pushing" up of water onto land by winds contained in storms, such as hurricanes. Factors determining the height of the storm surge include the strength of the wind in the storm, speed of storm, and slope of the sea floor leading to the shore, and stage of tide (high or low). For more information, visit http://www.nhc.noaa.gov/HAW2/english/storm_surge.shtml.

Materials
- Graphs and charts of calculated and actual estimates of sea level rise
- Topographic maps of local areas 1:24000 scale with 5 ft contour lines, (available at your county Natural Resources Conservation Service office)
- Non-permanent marking pens

Sea Level Rise and Storm Surge Worksheet

Procedure

Part 1. Becoming familiar with topographic maps

1. Locate the following on your topographic map and note the color:

2. Using the non-permanent markers, trace the shoreline of the area, circle major buildings such as schools, churches, and mark several main roads.

3. Find and trace the 5 foot contour lines on your map using a different color marker.

Part 2. Determining flooded areas from sea level rise

1. Using the data and information provided in appendix 1, calculate the annual average sea level rise in cm per year.

Global ____________________________________

Chesapeake Bay ____________________________

2. Determine how many years it will take to flood the areas you marked above under historic sea level rise conditions and for predicted sea level rise conditions.

3. Use the contour lines on your topographic map to draw in the new coastline after 100 years using the global predicted sea level rise rates.

4. Calculate the future 100 year potential sea level rise rates for the Chesapeake Bay using the data from the historic sea level rise rates for the global ocean vs. Chesapeake Bay

5. Will there be a difference in the areas flooded using this potential sea level rise for Chesapeake Bay?

Part 3. Determining flooded areas from a storm surge

1. A hurricane in your area produced a storm surge of 6 feet.

2. Would the impact of the storm be greater or less if it hits land at 8:00 AM vs. 2:00 PM today? Explain your answer.
To determine your response you will need to visit the following websites:
Local Chesapeake Bay:
http://tidesonline.nos.noaa.gov/
www.cbos.org
National Buoys systems:
http://www.csc.noaa.gov/coos/

Part 4. Sea Level Rise and Glaciers and ice caps

(Adapted from: http://en.wikipedia.org/wiki/Sea_level_rise)

Each year about 8 mm (0.3 inches) of water from the entire surface of the oceans goes into the Antarctica and Greenland ice sheets as snowfall. If no ice returned to the oceans, sea level would drop 8 mm every year. Although approximately the same amount of water returns to the ocean in icebergs and from ice melting at the edges, scientists do not know which is greater -- the ice going in or the ice coming out. The difference between the ice input and output is called the mass balance and is important because it causes changes in global sea level.

Ice Shelves float on the surface of the sea and, if they melt, to first order they do not change sea level. Likewise, the melting of the northern polar ice cap which is composed of floating pack ice would not significantly contribute to rising sea levels. Because they are fresh, however, their melting would cause a very small increase in sea levels, so small that it is generally neglected. It can however be argued that if ice shelves melt it is a precursor to the melting of ice sheets on Greenland and Antarctica.

Scientists lack knowledge of changes in terrestrial storage of water. Between 1910 and 1990 such changes may have contributed from -1.1 to +0.4 mm/yr.

If ice that is floating on the ocean melts, the rise is sea level is negligible. However, as ice is formed over land, melting can significantly increase sea level. It is predicted that if all glaciers and ice caps melt, the projected rise in sea-level will be around 0.5 m. If the melting includes the Greenland (ice over land), the predicted rise is about 7 meters. If both the Greenland and Antarctic ice sheets melt, then the rise is a more drastic 68.8 m.
1. Will any of the places you have marked be above water if the ice sheets on Greenland melted? Mark these places.

2. Predict which areas will be above water if ice sheets on both Greenland and Antarctica melt.