Wind Effects - A Case Study
Does weather have an impact on the height of tides?
Objectives
Students will be able to:
- use graphs and other data to
determine the impact of a hurricane on the New Jersey
coast
- hypothesize what would happen if
the hurricane made land fall at a different time
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Materials
computers with Internet access
Student Worksheet
graph paper
colored pencils
optional: Excel
Background
Hurricane Floyd Passes over Avalon, New Jersey
Between 4 and 5 pm on September 16, 1999, the center of Hurricane Floyd passed
directly over an automated coastal monitoring station located on the beach in
Avalon, New Jersey. The monitoring station is part of the New Jersey Coastal
Monitoring Network operated by Stevens Institute of Technology, in Hoboken, New
Jersey. Tropical Depression Floyd formed on September 7th in the western
Atlantic. By September 10, Floyd reached hurricane strength and its center
of circulation was located approximately 200 miles east-northeast of Barbuda in
the northern Leeward Islands. Over the next two days Floyd moved west-northwest,
strengthening to a category 4 hurricane. On the morning of September 15th,
Floyd was located about 300 miles south of Wilmington, North Carolina.
Floyd took a turn to the north during the day on the 15th and decreased in
intensity to a category 2 hurricane. At 3 am EDT Floyd made landfall at
Cape Fear, North Carolina. Please review the
Stevens case study or NOAA case Study as it
will serve as the basis for this lesson.
MLLW is mean lower low water, which is a site-specific datum determined by
averaging the lowest of the 2 low tides that occur each day over a 19-year tidal
epoch. For tide gages with less than 19-years of record, this datum is estimated
using correlation with long-term tide gages.
In this lesson, students will use archived data from the Hurricane Floyd event
to understand how wind can effect tide height.
Procedure
1. Plot the following tide prediction data for Atlantic City, New Jersey,
and create a line graph.
|
Tide Chart for
Atlantic City, NJ (Steel Pier) - 9/14/99 to 9/17/1999 |
|
Date |
Day |
High |
Low |
High |
Low |
High |
| Time |
ft |
Time |
ft |
Time |
ft |
Time |
ft |
Time |
ft |
| 9/14 |
Tue |
|
|
04:59 |
0.49 |
11:14 |
4.53 |
17:29 |
0.68 |
23:28 |
3.98 |
| 9/15 |
Wed |
|
|
05:38 |
0.76 |
11:58 |
4.39 |
18:18 |
0.92 |
|
|
| 9/16 |
Thu |
00:14 |
3.70 |
06:21 |
1.01 |
12:46 |
4.27 |
19:12 |
1.11 |
|
|
| 9/17 |
Fri |
01:05 |
3.47 |
07:09 |
1.20 |
13:39 |
4.19 |
20:11 |
1.21 |
|
|
| 9/18 |
Sat |
02:03 |
3.34 |
08:05 |
1.30 |
14:37 |
4.19 |
21:11 |
1.21 |
|
|
2. Using the line same graph, plot the following
measured tide data for Atlantic City, New Jersey. Use a
different color to complete the line.
|
Measured for Atlantic City, NJ (Steel
Pier) - 9/14/99 to 9/17/1999 |
|
Date |
Day |
High |
Low |
High |
Low |
High |
| Time |
ft |
Time |
ft |
Time |
ft |
Time |
ft |
Time |
ft |
| 9/14 |
Tue |
|
|
04:59 |
|
11:14 |
|
17:29 |
|
23:28 |
|
| 9/15 |
Wed |
|
|
05:38 |
1.3 |
11:58 |
4.9 |
18:18 |
1.5 |
|
|
| 9/16 |
Thu |
00:14 |
4.5 |
06:21 |
2.3 |
12:46 |
5.7 |
19:12 |
0.7 |
|
|
| 9/17 |
Fri |
01:05 |
2.6 |
07:09 |
0.1 |
13:39 |
3.5 |
20:11 |
0.1 |
|
|
| 9/18 |
Sat |
02:03 |
2.3 |
08:05 |
0.9 |
14:37 |
3.8 |
21:11 |
|
|
|
3. Using the graph, answer the
following questions on the Student Worksheet.
Were there any significant discrepancies between the predicted
and measured water levels? Which day and time?
Can you hypothesize as to what might have occurred?
4. Review the following data recorded by the Coastal
Monitoring Station presented below as time histories (Sept. 15
to Sept. 18). NOTE: The wave/tide gauge is located
approximately 1/4-mile offshore in an average water depth of
13.1 ft MLLW.
5. Using the time histories, answer the following
questions on the Student Worksheet.
Why would a sudden drop in barometric pressure be of
significance? When did the drop occur?
What happened to the Wind Speed, Gusts and Direction at the
same time of the sudden drop in barometric pressure?
What are all of these meteorological conditions an indication
of?
Comparing the water level data you graphed to the
meteorological conditions, why do you think the predicted
water levels did not correlate with the measured water levels?
Was your hypothesis correct?
Satellite Images of
Hurricane Floyd
Rutgers Site
6. Reviewing the predicted water levels and the
meteorological information, how might the water levels been
affected if the storm passed over Atlantic City at 11:30 am
instead of 4:00 pm on September 16th? At 6:00 am?
7. The most damaging aspect of Hurricane Floyd was not
felt along the New Jersey coast. Use the following links
to determine which area of New Jersey received the most water
damage from the storm.
 |
This figure shows the total rainfall for
a 2.5 day period between September 14th and 17th. Forty percent of the
watershed was covered by 10 to 15 inches of rain. The red areas
represent the heaviest amounts of rain.
*from the Rutgers
Hurricane Floyd web page |
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Assessment
1.
Responses to questions on Student Worksheet.
2. Use links to real time data sources for your area. Do you think
that the weather over the next week will impact the predicted water height?
Explain why or why not. Revisit the sites after one week to see if the
prediction was valid.
Extension
North Carolina was the hardest hit by this storm:
F.E.M.A. totals
Earth Observatory
Besides the devastating effects of flood waters, what other problems did North
Carolina experience due to Hurricane Floyd?
How much money did it cost North Carolina to clean up from Hurricane Floyd?
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