1. Florida Institute of Technology
Effect of Wind Reduction Factors on Forecasting Circulation in an Estuary
2016 AMS Annual Meeting
January 14th , 2016
Atousa Saberi, Robert J. Weaver, Peyman Taeb, Steven M. Lazarus, Michael E. Splitt, Bryan P. Holman and Jeff Colvin
Florida Institute of Technology
Good afternoon everybody. My name is Atousa Saberi recently graduated student from Florida Institute of Tech. and I’m presenting our team’s research the on effect of wind reduction factors on forecasting wind driven Circulation in an Estuary.

2. Overview Statement of the Problem Study Site
Methodology and Numerical Modeling
Results and Discussion
Conclusions
Next Steps

3. Importance of Wind Resolution in Hydrodynamics Modeling
Using high resolution WRF model for forecasting wind is computationally expensive
Could we develop a new method that deals with wind over land that is not as expensive as WRF?
ADCIRC hydrodynamics model is able to do the downscaling. Does ADCIRC perform well in the regions where we have the land mask? What are the errors involved?
The resolution of the wind inputted to a hydrodynamics model is very important to truly estimate the circulation, water level and strength of the current. The more the resolution the better the forecast, but it is computationally expensive to come up with a high resolution WRF model…. What are the error involves with ADCIRC?
To answer these questions, 3 different test cases with different wind resolutions are studied which will be explain in further slides…

4. Indian River Lagoon Length: 250 Km Width: 2- 4 km Average Depth: 1.2 m
Max. Depth: 4 m
Inlet
You heard a lot about the IRL earlier in the conference.

5. Methodology Initial Grid WRF GFS SMS Meteorological Forcing
Modified Grid
ADCIRC
So here is our approach to study the effect of wind resolution on our hydrodynamics model.
SMS: has a graphical user interface for developing computational grids and we used it for grid refinement in the vicinity of inlets and channels…
WRF: modeling different resolution of winds
Elevation Time-series

6. Addition of the Causeways
Grid Development
Addition of the Causeways
Eau Gallie Causeway
Pineda Causeway
Railroad bridge
Nasa Causeway
528 Causeway
Merritt Island Causeway
The maximum resolution in the IRL was in the order of 100 m and this resolution was not enough in the vicinity of the inlets and in narrow canals like the Barge Canal that have a width of 80 m.
the environmental impacts of these causeways on the IRL have been debated for many years (Morris
et al., 2003). The causeways can restrict normal flow of water and alter local circulation patterns. In this study, the causeways along the IRL Since some of the causeways are narrow, the minimum edge size of the
mesh is reduced down to 30 meters.
Titusville Causeway
Melbourne Causeway

7. The Final High Resolution IRL
EC95d northwest Atlantic domain.
The final grid has: nodes 309, 000 elements

8. ADCIRC Simulations Wind-only Simulation: WRF Low Resolution Wind
3 series of wind only simulations with run time of 3 days (March 5th to 8th, 2015)
Wind-only Simulation: WRF Low Resolution Wind
Spatial Resolution: 0.1 deg.
Temporal Resolution: 3 hrs
Wind-only Simulation: WRF High Resolution Wind
Spatial Resolution: deg.
Temporal Resolution: 3 hrs
Wind-only Simulation: WRF Low Res. Wind with the addition of ADCIRC’s reduction factors
Surface Canopy
Surface Directional Roughness

9. Wind Speed difference between hi-res and low-res WRF runs

10. Depiction of Wind Speed differenceB
Red means hi-res WRF run has faster wind speeds.
Blue means low-res WRF run has faster wind speeds.

11. Time-series of Wind Speed Difference Point A
Point A- resolved as land in the LO-RES WRF run.
Much higher wind speeds in the hi-res WRF throught the event.

12. Time-series of Wind Speed Difference at Point B
Point B – Resolved as Water in LO-RES run but land in HI-RES run.
Much lower wind speeds in the hi-res WRF throught the event. B
… and we are going to see how does this difference are being reflected in our hydrodynamic model as we force our model with these winds…

13. Elevation Time-series at Point A
Because Point A was resolved as land in the lo-res wind, due to the land mask we have the adcirc double downscales the wind as a result adcirc elevation is as low as lo-res wind…

14. Elevation Time-series at Point B

15. Validation

16. Summary and Conclusion
In the regions LO-RES wind has the land mask the downscaling with ADCIRC is doubling the downscaling
The wind magnitude is being underestimated and causes error in forecasting
In the regions LO-RES wind has no land mask the downscaling with ADCIRC is working properly
Could we develop an integrated approach by using WRF model where we have land mask and use ADCIRC to reduce the wind where we don’t have land mask?
Could the meteorologists give us a potential wind file where there is land mask, so that ADCIRC do the downscaling?

17. ST. Johns River Water Management District
Acknowledgement
I’d like to thank NOAA CSTAR for funding our research
NOAA Collaborative Science, Technology, and Applied Research (CSTAR) Program
grant #NA14NWS
Department of Marine and Environmental Systems at the Florida Institute of Technology
ST. Johns River Water Management District

18. References
Smith, N. P Tidal and Low Frequency Flushing of a Coastal Lagoon Using a Flexible Grid Model. Coastal and Estuarine Studies, 50,
Luettich, Rick A., Westerink, J. J., & Schener, Norman W ADCIRC: An Advanced three-dimensional circulation model for shelves, coasts and estuaries, report 1: theory and methodology of ADCIRC-2DDI and ADCIRC-3DL. Tech. Rept. Dredging Research Program, DRP.
Zundel, Alan K Surface-water Modeling System reference manual: Version 9.2. Brigham Young University Environmental Modeling Research Laboratory.

19. Thank You Any Question?