As early as 2008, GLEN scientists began measuring evaporation over the Great Lakes to help reduce the uncertainty of the lakes’ water balance. Station locations were strategically chosen to provide robust estimates of open-water evaporation from Lakes Superior, Huron, Michigan, and Erie. An additional site in eastern Lake Ontario was added in 2016. The source area, or turbulent flux footprint, for four of the offshore lighthouse sites (Stannard Rock, Granite Island, Spectacle Reef, and White Shoal) represents open water that extends at least 10 kilometers in all directions. Granite Island is surrounded by open water in all directions, but does occasionally receive a small amount of disturbance from the island itself (e.g., during summer under low-wind conditions). The Long Point site on Lake Erie and Nine Mile Point site on Lake Ontario both receive considerably more land influence (to the west and northeast of the lighthouses, respectively), but this influence is largely removed through wind-direction filtering during post processing. Instrumentation at each site was installed with little to no obstruction from the prevailing wind direction.

GLEN scientists have currently defined three levels of data processing and QA/QC for the high-frequency eddy covariance data collected at these sites. Level 0 data represent eddy covariance and ancillary meteorological data that have undergone no QA/QC (including no flux corrections). Level 1 eddy covariance data have undergone basic flux corrections, including removal of latent and sensible heat spikes and a visual level of quality control. Level 3 data (not yet available) are derived from level 2 and contains additional flux filtering and gap filling. All data listed below are currently Level 1 data through 2018, as funding for the GLEN project ended in 2019.

Data Availability

Stannard Rock Granite Island Spectacle Reef White Shoal Long Point Nine Mile Point
Years Available 2008-2018 2010-2018 2009-2018 2012-2018 2012-2018 2016-2018
Principle Investigator C. Spence J. Lenters P. Blanken P. Blanken C. Spence C. Spence
Data Level 1 1 1 1 1 1
Latent Heat
Air Temperature
Friction Velocity
Momentum Flux
Wind Speed
Wind Direction
Relative Humidity
Barometric Pressure
Incoming Shortwave Radiation
Incoming Longwave Radiation

Half-hourly data for each year and each station are available from GLOS as binary netCDF files:


Individuals who wish to download and use the GLEN data are asked to please first contact the principle investigator who contributed the data. This will allow the investigators to discuss and review the intended use of the data and participate in any subsequent publications, if appropriate. The GLEN data investigators contact information can be found on the Contact page.

When referencing GLEN data in a publication, please include the following statement:

The data used in this research were kindly provided by the Great Lakes Evaporation Network (GLEN), with data compilation and publication provided by LimnoTech under Award/Contract No. 10042-400759 from the International Joint Commission (IJC) through a sub-contract with the Great Lakes Observing System (GLOS). The statements, findings, conclusions, and recommendations are those of the author(s) and do not reflect the views of GLEN, LimnoTech, the IJC, or GLOS.


These Great Lakes evaporation data (the "data") belong to the station owners and operators (the “owners”). These data were collected in support of public hydrometerological research on the Laurentian Great Lakes. The owners of the data maintain access rights to the data for a period of two years for the purposes of quality assurance / control and publishing. Two years after production, the data set is considered public information and is free for academic and educational purposes. The people who gathered the data over the entire period of record are the "providers." Users of the data are asked to acknowledge the providers, noting the key references listed on the "Publications" tab of this website. If users cannot complete research objectives without these data, they are asked to contact the providers to solicit input and co-authorship in any scientific articles. The authorized use of these data is limited to academic and educational purposes only, and are NOT for operational or commercial purposes. THESE DATA ARE PROVIDED "AS IS" AND IN NO EVENT SHALL THE PROVIDERS BE LIABLE FOR ANY DAMAGES, INCLUDING, WITHOUT LIMITATION, DAMAGES RESULTING FROM LOST DATA OR LOST PROFITS OR REVENUE, THE COSTS OF RECOVERING SUCH DATA, THE COSTS OF SUBSTITUTE DATA, CLAIMS BY THIRD PARTIES OR FOR OTHER SIMILAR COSTS, OR ANY SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, ARISING OUT OF THE USE OF THE DATA. The accuracy or reliability of the data is not guaranteed or warranted in any way, and the providers disclaim liability of any kind whatsoever, including, without limitation, liability for quality, performance, merchantability and fitness for a particular purpose arising out of the use, or inability to use the data.