Granite Island

Latitude: 46°43'0" N
Longitude: 87°24'0" W
Site Elevation: 183 meters above sea level

Granite Island is a 2.5-acre island in Lake Superior, roughly 12 miles north of Marquette in the Upper Peninsula of Michigan. The island is composed of granite rock and rises nearly 60 feet above the surface of Lake Superior. The lighthouse began operation in 1869, was automated in 1937, and then was privately purchased and restored by Scott and Martine Holman in 1999.

In 2009 Dr. John Lenters, then an associate professor at the University of Nebraska-Lincoln, installed an eddy covariance system and weather station to measure lake evaporation and other atmospheric variables. In 2013 Northern Michigan University took ownership of the eddy covariance station, with LimnoTech helping to maintain the site. Meteorological data from the lighthouse are sent to the National Data Buoy Center where they can be viewed in real-time at http://www.ndbc.noaa.gov/station_page.php?station=GRIM4