Workshop on NASA and the U.S. Great Lakes Theme 3, Applications: Coastal Processes

1. Workshop on NASA and the U.S. Great LakesTheme 3, Applications: Coastal Processes April 12-13, 2010 Robert Shuchman, Ph.D., Michigan Tech University Jim Churchill, Ph.D., Woods Hole Oceanographic Institute Chin Wu, Ph.D., University of Wisconsin (Madison and Milwaukee) Guy Meadows, Ph.D., University of Michigan

2. Theme 3 – Coastal Processes • What are the important processes? Sediment Resuspension • Influenced by surface waves, thermal overturn, wind-driven currents … • Affects coastal productivity, lake chemistry … Wind/Wave Driven Setup of Coastal Lake Levels • Related to bathymetry • Wave setup may be important in certain locations/circumstances Dissipation of Wind-driven Currents • Seiching • Friction spindown • Internal wave interaction with the bottom • Rip current formation

3. Important Processes (cont. of partial list) Transport of Riverine Input • Can enter the lake as a positively or negatively buoyant plume • Plume dynamics can be influenced by sediment load Coastal Erosion • Influenced by lake and atmospheric processes • May be difficult to distinguish from coastal resuspension • Lake ice effects Differential Heating in the Coastal Zone • Thermal Bar (4oC) formation in spring • Thermal front formation in summer and early fall 3

4. Important Processes (cont. of partial list) Coastal Bluff Erosion & lakebed downcutting 4

5. Important Processes (cont. of partial list) Coastal freak waves 5

6. Theme 3 – Coastal Processes • What do we want to measure? • Surface winds • Surface gravity waves • Temperature structure • Internal waves • Water level (short and long time scales) • Sediment transport • 3-Dimensional current structure • Rip currents • CPA (chl, doc, and sm) concentrations • Location of Harmful Algal Blooms (HABs) • Lake ice • Primary productivity • Bathymetry • Lake Bottom Type • Others Overarching Issue: Coastal processes in the Great Lakes determine the ecological health and recreational use of the Great Lakes waters.

7. Science Questions • Level 1 – Science Questions • Spatial and temporal scales required for effective monitoring • Integration of in situ monitoring with satellite derived observations • Use of data assimilation approaches to combine geophysical based models with observations to obtain 3-D information • Level 2 – Science Questions • Can we use satellite based altimeters and LIDARs to measure lake level (accuracy and precision) • How do we obtain the required 3-D current information • Improved atmospheric corrections for better discrimination of first few km of nearshore lake

8. NASA-based Satellite Observations of the Great Lakes • General Requirements • Daily observations • 100 m or better spatial resolution • All weather for wind, waves, water level, lake ice, and currents • Temperature, CPAs, sediment, HABs electro-optical based and thus weather dependent • Commitment for long term monitoring (decades) – not just proof of concept

9. NASA-based Satellite Observations of the Great Lakes • Specific Requirements • Synthetic Aperture RADAR (SAR) for wind, waves, ice, surface current (?) • RADAR altimeter for water level (?), sea ice extent, winds, significant waves height, and currents (?) • LIDAR for water level (?) • Microwave radiometer for surface lake temperature (?) • MODIS enhancement • 100 m or better spatial resolution • Additional MERIS like bands for HABs • LANDSAT enhancement • LANDSAT swath / 3-day revisit • Add additional water bands for CPAs and HABs • 5-15 m resolution

10. Supporting Information

11. Satellite Derived Great Lakes Information • Water Quality Parameters • CPAs (chl, doc/cdom/sm) • Optical depth/turbidity • Primary productivity • Harmful algal blooms (HABs) • Sediment blooms • Temperature • Lake Bottom Mapping • Depth • Bottom features (cladophora, rock, sand, etc.)

12. Satellite Derived Great Lakes Information (Cont) • Lake Ice • Extent • Thickness (?) • Shoreline Mapping • Land/water boundary • Wetlands • Invasive species mapping (Phragmites) • Lake State • Surface wind • Surface waves • Internal waves • Currents

13. Satellite Systems that Provide Observations on the Great Lakes

14. Satellite Systems that Provide Observations on the Great Lakes (Cont)

15. Mapping Cladophora in the Great Lakes Using Remote Sensing • The issue: More Cladophora filamentous green algae is growing in the Great Lakes, causing fouled beaches, clogged water intakes, bird die-offs from avian botulism; related to spread of zebra and quagga mussels • What we are doing about it: We are mapping its extent and amount; identifying point sources of phosphorous that increase growth; developing a Decision Support System (DSS) to predict spread along shorelines and help with removing detached Cladophora • The bottom line: Methods can be used to create the maps, identify point sources of phosphorous, demonstrate remediation process • The project team: Robert Shuchman, Marty Auer, Colin Brooks, and Mike Sayers Photo: S. Higgins

16. Cladophora Mapping Study Details We have developed new techniques for mapping Cladophora using satellites, using depth-correction algorithm Applied to Landsat and high-res Quickbird and GeoEye-1 imagery Recent results indicate that 49,420 tons of Cladophora biomass is present at Sleeping Bear Dunes Our work will help natural resources managers make cost-effective decisions for reducing Cladophora; help energy plants avoid shut-down Applied to GLRI to extend mapping and decision support work Algorithm specifics: Lyzenga Depth Corrected Radiance Algorithm – ln(Li – Lsi) Depth corrected radiance values and water attenuation coefficients used in least squares regression model to derive depth invariant bottom type index Image processing techniques applied to classify bottom types based on depth invariant index values Successfully mapped Cladophora extent in SBDNL in Lake Michigan Extending to elsewhere in the Great Lakes – recently mapped Pickering Nuclear Power Plant area near Toronto

17. Studying the Change in Light Penetration in the Great Lakes Over Time • Apparent water bottom visibility depth was calculated by examining the depth at which the majority of the depth corrected radiance pixels had values less than 1, indicating optically deep water. • This procedure was done for clear green band (2) Landsat TM scenes from 1974-2009. • GLERL bathymetry was used as the depth reference in this analysis. • Shows influence of major events in the Great Lakes over time - GLWQA, introduction of zebra mussels.

18. Lake Michigan Images

19. Spatial Distribution of (a) sm Concentration, and (b) the smVoluminal Content Per km2

20. A Comparison of (a) the Spatial Distribution the smVoluminalContent per km2 , and (b) the Contours (in m) of Bottom Sediment Accumulations Reported by Schwab et al.

21. Rip Current Importance • Over 80% of all surf related rescues are attributable to Rip Currents • According to the U.S. Lifesaving Association, in 1999 there were over 23,000 rip related rescues along U.S. beaches • It is estimated that each year nearly • 100 people drown from rip currents • 12 deaths in Michigan in 2003 http://www.carefulparents.com/rip-currents.htm

22. Components of a Rip • Neck • Strongest current • Head • Current disperses beyond the breaker line • Longshore Current or Feeder • Feeds the rip • Breaker Zone • Slow onshore movement between rips

23. Rip Currents Swift, narrow currents that carry water, sand and debris off shore As long as 1 kilometer, Ranging from less than 10 to over 30 m in width With maximum velocities over 2 m/s Strongest outward moving current occurs where the wave height is lowest attracting unwary bathers to the more tranquil looking area of the beach.

24. Mechanics of Rip Current Generation • Variable Longshore Bathymetry • Variations in Longshore Wave Height • Intersecting Wave Trains • Edge Waves • Coastal Structures

25. Great Lakes Basin Dynamics • Seiches and Kelvin Waves • Contribute additional water to nearshore zone • Strong Air/Sea Temperature Differences • Drive large and rapid wave growth • Changing Water Levels • Effects on nearshore bathymetry and sediment supply • Climatological Cycles (Meadows et al., 2000) • Stronger winds lead increased water levels by 18 months • Sets stage for increased rip current frequency on low water levels.

26. Seiching

27. Water Levels Vary on Many Scales • Long term, water levels recorded from 1860 to present • Decadal Changes • Seasonal Changes • Daily Variations Eagle Harbor in Ephraim, WI 10-25-99 http://www.glerl.noaa.gov/seagrant/glwlphotos/Michigan/LakeMichiganLevels.html#High

28. Great Lakes Water Levels

29. High Frequency (HF) Radar and its Application to Fresh Water • Shore-Based Automated System • Two Synchronized Stations • Separated by 5-25 km • Range of 50-100 km • Demonstrated Mapping Capabilities • Currents • Ice • Waves • Wind • Vessel Tracking http://marine.rutgers.edu/cool/

30. HF Conclusions • Useful tool for freshwater application on 25km range near water surface • Embayments • River plumes • Rivers • Estuaries • Future Directions • Modification of a single band system for increased range at higher frequencies

31. The Role of NASA • Nearshore Bathymetry • Wave Growth and Propagation • SST and Nearshore Waves • Long Period Wave Motions (Seiche and Infra-gravity) • Rip Identification and Propagation