final exam individual exercises part a hurricanes and tsunamis
Instructions
Water Levels
This part of the individual exercises requires examination of verified data for water level at various tide stations on specific dates to explore the changes in water levels associated with hurricanes and tsunamis. The effect of Hurricane Issac on the barrier islands of North Carolina was examined in Part C of the Coastal Processes Exercise and the effects of Hurricane Sandy are considered in Part C of the Phase II Group Activities. Here, the aim is to examine storm surges and compare the nature of the disturbance of water level compared to tsunami, which were explored in Part A of the Phase II Group Activities.
On the NOAA website there is a separate webpage for active stations (Active Tide Stations) in the various regions. From this page the specific stations noted below can be selected, and the data display modified to provide the target time range using the Begin Date and End Date settings, with the Datum set to MLLW.
The display shows the predicted tide (blue) and the verified water level (green), with all measurements in feet.
The specific stations to examine for this part of the exercise on the specified dates are as follows:
- Cape Hatteras, North Carolina (Station 8654467; Hatteras; Figure 1) for September 1 – 6, 2010.
- Grand Isle, Louisiana (Station 8761724; Grand Isle 2005 (Links to an external site.); Grand Isle 2012) for August 26 – 31 2005 and August 26 – 31 2012.
- Waveland Yacht Club, Mississippi (Station 8747437; Waveland 2012 (Links to an external site.); Figure 2) for August 26 – 31 2012.
- Hilo, Hilo Bay, Kuhio Bay, Hawaii (Station 1617760; Hilo (Links to an external site.)) for October 28 2012.
- Kahului, Kahului Harbor, HI (Station 1615680; Kahului) for October 28 2012.
Figure 3: Water levels recorded for Waveland in August 2012.
Figure 3: Water levels recorded for Hilo Bay in October 2012.
Question 1 5 pts
Examine the verified tide for Hatteras, North Carolina, and describe the difference between the predicted tide and the verified water level. What was the magnitude of the difference in water levels in early September 2010 at this station and how does this elevated water level compare with the normal tidal range at this location? What was responsible for these abnormal water levels based on the information from the hurricane tracks for 2010?
A strong answer will will include specific details of the magnitude of the elevated water levels relative to the normal tidal range, explain why they were elevated, and relate this specific event to the data for Atlantic hurricanes in 2010 provided by the map of their tracks.
Question 2 5 pts
Examine the verified water level for Grand Isle, Louisiana, in 2005 and describe the difference between the predicted tide and the verified water level. What was the magnitude of the difference in water levels in August 2005 at this station and how does this elevated water level compare with the normal tidal range at this location? What was responsible for these abnormal water levels based on the information from the hurricane tracks for 2005?
A strong answer will will include specific details of the magnitude of the elevated water levels relative to the normal tidal range, explain why they were elevated, and relate this specific event to the data for Atlantic hurricanes in 2005 provided by the map of their tracks.
Question 3 5 pts
Examine the verified water level for Grand Isle, Louisiana, and Waveland, Louisiana, in 2012 and describe the difference between predicted tide and the verified water levels. What was the magnitude of the difference in water levels in August 2012 at these stations and how does the elevated water levels compare with the normal tidal range at these locations? What was responsible for these abnormal water levels based on the information from the hurricane tracks for 2012? How does the magnitude of the storm surge for the hurricane in 2012 measured at Grand Isle, Louisiana, and Waveland, Mississippi, compared to that measured for Grand Isle in 2005 and does the storm surge appear proportional to the category of the hurricanes responsible?
A strong answer will will include specific details of the magnitude of the elevated water levels relative to the normal tidal range, explain why they were elevated, and relate this specific event to the data for Atlantic hurricanes in 2012 provided by the map of their tracks. It will also compare the three sets of data and discuss differences in the magnitude of their storm surges relative to the category of the hurricanes responsible.
Question 4 5 pts
Describe the differences between the verified and predicted water levels at Hilo and Kahului in October 2012, and discuss the likely cause of these discrepancies, also explaining the reason for any differences between the two data sets in terms of the timing and magnitude of water disturbances.
A strong answer will specify the discrepancies between the verified and predicted tides in terms of their timing and magnitude for each of the stations and the differences between the two stations. It will also explain the differences by reference to phenomena that disturb water levels, as observed at other locations in the Pacific.
Question 5 5 pts
Bonus Question (5 pt)
Can the phenomena observed in the water level data for hurricanes and tsunamis be readily distinguished?
A strong answer will describe specific aspects of the differences in water levels recorded for storm surges associated with hurricanes and disturbances produced by tsunami, explaining how they appear differently in the water level records.
