LIDAR–based measurements of wind characteristics within the marine

boundary layer over Lake Michigan

Frank J. Marsik, Aline Cotel and Kyle Chudler (University of Michigan)

Guy Meadows and Neel Desai (Michigan Technological University)

2014 Great Lakes Operational Meteorology WorkshopAnn Arbor, Michigan

Outline• A bit of motivation….• Description of AXYS Wind SentinalTM buoy• Description of data analysis methodology• Presentation of turbulent kinetic energy results from nearshore location (2011)

• Presentation of vertical wind profile data from mid-lake plateau location (2012)

Introduction Methodology Nearshore Mid-Lake Summary

Motivation• Overall goal of the project

• Acquire data to investigate economic viability of offshore wind energy production in Lake Michigan

• UM/MTU Efforts

• Obtain a better understanding of turbulent kinetic energy (TKE) characteristics over the lake

• Investigate season variation of vertical wind profile structure

Introduction Methodology Nearshore Mid-Lake Summary

Washtenaw County• What: Wind energy feasibility study

for Washtenaw County (2008-2009)

• Where: Chrysler Proving Grounds, Chelsea, MI

• Why: Determine if wind energy production would be financially viable in the county

• American Wind Energy Association (AWEA) indicates that utility scale wind power plants require minimum average wind speeds of 6 m/s (13 mph) to be financially viable.

Introduction Methodology Nearshore Mid-Lake Summary

http://www.ewashtenaw.org

State of Michigan• Estimated wind speeds over land

• Generally less than 6 m/sec

• Estimated wind speeds offshore

• Generally 7-9 m/sec

Introduction Methodology Nearshore Mid-Lake Summary

Source http://www.michigan.gov/images/MI_Final_SPD50m_9Sept04_115624_7.jpg

Field Monitoring Periods and Sites

65 km

MAY – DEC 2012

Introduction Methodology Nearshore Mid-Lake Summary

Summary for 2012 and 2013 periods

Introduction Methodology Nearshore Mid-Lake Summary

Courtesy of Jim Edmonson, Grand Valley State University

Key point: On average, winds at all levels exceed 6 m/sec threshold.

AXYS WindSentinelTM buoy• Vindicator Laser Wind

Sensor (hereafter, LWS)

• Capable of measuring wind velocity in three directions (U,V, and W) up to 175 m above the water surface

• One-second wind velocity data was collected and averaged over six 40-m vertical bins

• Horizontal wind data was motion compensated

Introduction Methodology Nearshore Mid-Lake Summary

Additional measurements

• Two, three-cup anemometers located three meters above surface

• Air and water temperatures

• Wave height and period

Introduction Methodology Nearshore Mid-Lake Summary

Analyses performed

• Thirty-second average turbulent kinetic energy (horizontal)

• Hourly-averaged horizontal wind speed

• For both of these analyses…

• Utilized AXYS-provided “data validity” flag

• Hourly average was accepted if over 50% of data was deemed valid

Introduction Methodology Nearshore Mid-Lake Summary

Lake Muskegon Evaluation

Introduction Methodology Nearshore Mid-Lake Summary

Horizontal separation distance ~ 400 m.

Lake Michigan – TKE Example December 04, 2011

Introduction Methodology Nearshore Mid-Lake Conclusions

Lake Michigan – TKE exampleIntroduction Methodology Nearshore Mid-Lake Summary

TKE

(m2/

s2)

Enhanced TKE throughthrough entire layer

sampled

Lake Michigan – Monthly mean example

Introduction Methodology Nearshore Mid-Lake Summary

Monthly Standard Deviation4-5 m/sec

Lake Michigan (June 10-13,2012)

Introduction Methodology Nearshore Mid-Lake Summary

June 11 June 12

Surface frontal zone passed site evening of June 11th.

Lake Michigan (June 10-13,2012)

Introduction Methodology Nearshore Mid-Lake Summary

Lake Michigan (June 10-13,2012)

Introduction Methodology Nearshore Mid-Lake Summary

Lake Michigan (Sept 10-13,2012)

Introduction Methodology Nearshore Mid-Lake Summary

September 12 September 13

Surface frontal zone passed site evening of September 12th.

Lake Michigan (Sept 10-13,2012)

Introduction Methodology Nearshore Mid-Lake Summary

Lake Michigan (Sept 10-13,2012)

Introduction Methodology Nearshore Mid-Lake Summary

Introduction Methodology Nearshore Mid-Lake Summary

Summary and Next Steps• Two years of seasonal vertical wind profiles (2012-2013)

• Vindicator Laser Wind Sensor

• Annual mean wind speed results • Encouraging for viability for offshore wind production

• Vertical TKE profiles• Preliminary results suggest enhanced TKE through depth of lower marine

boundary layer• Shows promise for providing guidance of gustiness/turbulence at hub

heights

• Vertical mean wind speed profiles• Effects of stability seen in both monthly and daily profiles• Next steps for me: Investigating applicability of power law relations for

wind energy potential prediction elsewhere in Great Lakes

Introduction Methodology Nearshore Mid-Lake Summary

Summary and Next Steps

where uref is wind speed at reference height zref and u2 is wind speed at reference height z2

• Hsu et al. (1994)• Suggests “p-value” of 0.11 for neutral stability typical of

open seas.• For variable stability and conditions in the Great

Lakes….???

𝑢2𝑢ref

=( 𝑧 2𝑧 ref )𝑝

Introduction Methodology Nearshore Mid-Lake Summary

Acknowledgements• GVSU Funding: U.S. Department of Energy

• Special thanks to Arn Boezaart, Jim Edmonson and many others at Grand Valley State University for sharing their data