MARQUETTE, MICHIGAN — Right now, scientists have limited observations of Great Lakes evaporation, greenhouse gases and even basic over-lake meteorology for informing Great Lakes predictive models.
Dr. John Lenters, the University of Michigan Biological Station’s new senior research specialist, is taking the helm of a collaborative project in the hopes of uncovering some of the mysteries surrounding the delicate dance between climate and hydrology in northern Michigan.
The first step is to invest in improved infrastructure for long-term, year-round monitoring of Great Lakes evaporation.
The Great Lakes Observing System (GLOS) recently awarded the University of Michigan Biological Station in Pellston just south of the Mackinac Bridge a two-year, $99,989 grant to repair, replace and service lake evaporation monitoring equipment at two Lake Superior sites that are the longest running of the seven sites in the Great Lakes Evaporation Network (GLEN).
One observation station is located at Stannard Rock Lighthouse and has been in operation since 2008, while the second site at Granite Island has been running since 2009.
Data from the GLEN network are being used to improve model forecasts of Great Lakes evaporation, water levels and lake-effect snowfall. The National Weather Service also uses the data for real-time weather observations and nearshore marine forecasts.
Last week Lenters drove up to Marquette in the Upper Peninsula and hitched a ride on a Michigan Department of Natural Resources boat to Granite Island to begin the process of upgrading the GLEN equipment at that site.
His initial work on the tiny, rocky island included replacing a krypton hygrometer for measuring humidity, repairing a CO2 sensor, troubleshooting real-time communication devices, cleaning optical sensors and checking battery fluid levels.
Lenters and the GLEN team have bigger goals.
The next steps are to undertake a complete overhaul of the instruments at Stannard Rock, while also integrating the GLEN data into the database of the AmeriFlux network, a collection of instrumented sites in North, South and Central America that measure ecosystem carbon dioxide, water and energy “fluxes,” or exchanges between the land surface and atmosphere.
UMBS manages two AmeriFlux towers near Douglas Lake and maintains high-quality, long-term data on forest carbon dynamics at the more than 10,000-acre research and teaching campus founded in 1909 — one of the nation’s largest and longest continuously operating field research stations.
Both of the Lake Superior GLEN sites also measure fluxes of carbon dioxide, heat and moisture, similar to what is done at the UMBS AmeriFlux towers. They also measure a full suite of meteorological variables including air pressure, temperature, humidity, wind, rainfall and solar radiation.
“AmeriFlux sites have historically tended to focus on terrestrial or forest systems, not lakes, while the GLEN network does not currently include any terrestrial sites,” Lenters said. “So the role of terrestrial evapotranspiration in driving variations in Great Lakes water levels, for example, has been very understudied.”
Lenters has a long-term interest in understanding the effects of changing lake temperature and ice cover on Great Lakes evaporation.
At the scientific field station in northern Michigan, he intends to build new synergies between the AmeriFlux and GLEN networks and improve our overall understanding of the Great Lakes water balance.
“The AmeriFlux towers at UMBS make similar ‘flux’ measurements, but over the forest canopy,” Lenters said. “So comparison of the data from UMBS and the GLEN network will allow us to quantify and understand the differences between ‘over-land’ and ‘over-lake’ fluxes — evapotranspiration from trees as compared to lake evaporation.
The GLEN network is a collaborative effort that includes UMBS, University of Colorado-Boulder, Environment and Climate Change Canada (ECCC) and the NOAA Great Lakes Environmental Research Laboratory (GLERL).
ECCC has already begun the process of integrating GLEN data from Stannard Rock with the AmeriFlux database. Lenters intends to do the same with the Granite Island data over the course of this new grant cycle that ends in April 2025.
Lenters recently joined UMBS after the retirement of Chris Vogel. Vogel managed the UMBS AmeriFlux field site since 1997.
“I study the effects of weather and climate on water resources, particularly the physical aspects of lakes such as water temperature, ice cover, evaporation and lake levels,” Lenters said.
Lenters has a Ph.D. and master’s degree in atmospheric science from Cornell University and a bachelor’s degree in physics and math from Hope College.
Prior to joining UMBS, he has served as an associate research scientist at Michigan Tech's Great Lakes Research Center, independent contractor with Lentic Environmental Services, senior scientist at LimnoTech, associate professor of applied climate science at the University of Nebraska-Lincoln, assistant professor of physics and meteorology at Lake Superior State University and post-doctoral researcher in lake-climate interactions and physical limnology at the University of Wisconsin-Madison.
