Great Lakes Coordinated Monthly Precipitation Data

Great Lakes Coordinated Monthly Precipitation Data Information

This dataset consists of the coordinated amount of monthly precipitation that has fallen over the basin areas of the different Great Lakes.  The data are presented in both mm and inches.  Most of the processing is done by the US Army Corps of Engineers Detroit Office using models developed by that agency and the Great Lakes Environmental Research Lab (GLERL) of NOAA.  The data is then verified by Environment and Climate Change Canada.

The archive begins in 1900 and the last year is inidcated by the version number.

Different methods used to calculate monthly precipitation for certain periods in record period. For more information on data sources reference this paper: *https://www.glerl.noaa.gov/pubs/fulltext/2015/20150006.pdf

An advancement made in most recent period, beginning in 1948. Data from 1948 to present calculated through AHPS model with GLERL DTP method. GLERL DTP method uses a group of meteorological stations surrounding the Great Lakes basin to calculate precipitation. In a recent study, it was found that some of the stations in the group were reporting erroneous data in recent years. Therefore, station list updated.

Also, AHPS model replaced with GLSHFS model. GLSHFS uses same method for calculating precipitation. With the model change to GLSHFS and the method's (GLERL DTP) improved station list, precipitation data updated back to 1948. 

Period  Current Method**  Previous Method** 

1900-1930  USACE-AWD  USACE-AWD

1931-1947  GLERL-MTP  GLERL-MTP

1948-2017  GLERL-DTP (GLSHFS)  GLERL-DTP (AHPS)

2018-YYYY  GLERL-DTP (GLSHFS) 

*Citation:

Hunter, T. S., Clites, A. H., Campbell, K. B., & Gronewold, A. D. (2015). Development and application of a North American Great Lakes hydrometeorological database—Part I: Precipitation, evaporation, runoff, and air temperature. Journal of Great Lakes Research, 41(1), 65-77.

**Acronyms

AHPS: Advanced Hydrologic Prediction System

AWD: Areally Weighted District

DTP: Daily Thiessen Program

GLERL: Great Lakes Environmental Research Laboratory

GLSHFS: Great Lakes Seasonal Hydrological Forecasting System

MTP: Monthly Thiessen Polygon

USACE: United States Army Corps of Engineers