Wind Direction, Intensity, and Dominant Wave Period Analysis

1. Keweenaw North Waterway Buoy Bob Shuchman: shuchman@mtu.edu Colin Brooks: colin.brooks@mtu.edu Nate Jessee: nljessee@mtu.edu Wind Direction, Intensity, andDominant Wave Period Analysis www.michigantechlakesuperior.org www.mtri.org

2. Analysis of Wind Direction and Speed • The Keweenaw Waterway North buoy gathered data from 7/9/2010 through 10/11/2010. Data is located at www.michigantechlakesuperior.org • A limited selection of records were removed for pre-deployment recording and sensor errors. • Data presented here represents dates from 7/9/2010 through 10/10/2010. • Two of the parameters collected were wind direction and wind speed. • This data was organized to determine the frequency, duration, and strength of winds moving off shore (from land to water) and on shore (from water to land).

3. General Wind Speed Analysis • For all records spanning from July 9th through October 10th 2010, wind speed measurements were recorded every ten minutes. • During this time span, wind speeds were less than 2 m/s for 11.41% of all records and wind speed was equal to zero for 0.07% of all records.

4. Analysis of Wind Direction and Speed • On shore and off shore winds are characterized based on the buoy location and the direction of the land. • Wind direction is absolute in that it indicates the direction that wind is moving towards. • On shore events are defined by consecutive recordings of winds with a direction between 45 and 225 degrees where 360/0 is north and 180 degrees as south. 45 On Shore Direction 225

5. Analysis of Wind Direction and Speed • Off shore events are consecutive recordings with a direction greater than 225 and less than 45 degrees where 360/0 is north and 180 degrees is south. Off Shore Direction 45 225

6. Buoy Location

7. Off Shore and On Shore Wind Direction Frequency Count of Recordings 59.5% The frequency of wind direction recordings described as either off shore or on shore, a total of 13453 records were taken from July 9th to October 10th.

8. Off Shore Wind Event* Duration Statistics Max 10.83 m/s Hours Description of off shore wind events, described by duration of events in hours. *Events are defined as time periods greater than 10 minutes where wind is consistently moving in the on or off shore direction.

9. Off Shore Wind Speed Statistics Wind Speed, m/s Summary of all off shore wind speeds for all off shore events.

10. On Shore Wind Event* Duration Statistics Max 5.92 m/s Min 4.32 m/s Ave. 4.98 m/s Hours Description of on shore wind events, described by duration of events in hours. *Events are defined as time periods greater than 10 minutes where wind is consistently moving in the on or off shore direction.

11. On Shore Wind Speed Statistics Wind Speed, m/s Summary of all on shore wind speeds for all on shore events

12. Off Shore and On Shore Event Duration Comparison Event Duration Statistics Hours

13. Off Shore and On Shore Wind Speed Comparison Wind Speed, m/s Represents all wind speed records for all events categorized as on or off shore

14. Major Off Shore Wind Event • Started on September 11th at 7:30 p.m. and lasted through September 15th at 1:00 a.m. Lasting a total of 77 hours, 30 minutes. • The event had the following characteristics: • Average wind speed: 8.07 m/s • Minimum wind speed: 5.31 m/s • Maximum wind speed 10.83 m/s • The following slide represents the temporal distribution of wind speed.

15. Major Off Shore Event, Wind Speed Graph Wind Speed, m/s

16. Major Wind Event Airport and Buoy Data Comparison Wind Direction * *Wind Directions indicate the actual direction that wind is moving

17. Wind Speed for Entire Data Series Wind Speed, m/s Represents all records from July 9th through October 10th.

18. Major Off Shore Wind Event Within Entire Time Line Wind Speed, m/s Represents all records from July 9th through October 10th and highlights the major off shore event

19. Dominant Wave Period Analysis • High Frequency (HF) Radar is sensitive to dominant wave period length. • Wave periods of small length, less than 2 seconds for example, may be unnoticed by HF Radar. • An analysis was performed to determine how frequently the dominant wave period dropped below a specific value. Each event was also characterized by the length of time the wave period value was below the threshold.

20. General Dominant Wave Period Analysis • For all records spanning from July 9th to October 10th, dominant wave period measurements were recorded every ten minutes. • The dominant wave period had a value of zero second for 0.01% of all records. • Also, dominant wave period value was less than 2 seconds for 15.98% of all records and greater than 5 seconds for 16.03% of all records between July 9th and October 10th.

21. Frequency and Duration of Wave Periods less than 2 seconds. Count of Events This graph represents 15.98 % of all records from July 9th through October 10th.

22. Frequency and Duration of Wave Periods less than 1.5 Seconds Count of Events This graph represents 3.95 % of all records from July 9th through October 10th.

23. Frequency and Duration of Wave Periods equal to zero seconds Count of Events This graph represents 0.01 % of all records from July 9th through October 10th.