File Inventory:

Date: 1 July, 2024

DATASET TITLE: Hydrological simulations across the Great Lakes basin from 1941 to 2020

DATASET CREATORS: Satbyeol Shin, Andrew D. Gronewold

DATASET CONTACT: Satbyeol Shin (satshin@umich.edu)

Research funding sources: NA22OAR4320150 (Cooperative Institute for Great Lakes Research - University of Michigan)

KEY POINTS
- We provide a comprehensive analysis of long-term hydroclimate changes across the Great Lakes basin from 1941 to 2020 using the WRF-Hydro model.
- By simulating key hydrological components such as ET, SWE, runoff, and surface soil moisture, we identify significant spatial and temporal variations within the region.
- This long-term analysis of hydroclimate trends provides valuable references for understanding historical hydrological changes and offers critical implications for future conditions. 
- These insights highlight the complexity and regional variability of hydroclimate interactions in the Great Lakes basin, emphasizing the need for localized studies and tailored management approaches.

RESEARCH OVERVIEW
Understanding long-term hydroclimate changes in the Great Lakes basin is crucial for effective water resource management and climate adaptation strategies. This study analyzed key hydrological components across the entire Great Lakes basin region, including evapotranspiration (ET), snow water equivalent (SWE), runoff, and surface soil moisture, over the period from 1951 to 2020, utilizing the Weather Research and Forecasting hydrological model (WRF-Hydro). The changes in annual magnitude and seasonality were assessed using Sen’s slope and apportionment entropy methods. Our findings reveal substantial spatial and temporal variations in hydroclimate trends across the Great Lakes basin. Temperature increases were found to have a more pronounced effect on ET compared to precipitation, with strong positive correlations between temperature and ET on an annual scale. SWE exhibited significant correlations with runoff primarily in the Superior basin, highlighting the unique hydrological processes influenced by its colder climate and prolonged ice cover. Surface soil moisture showed the least change, indicating its relative insensitivity to climatic variations compared to other variables. Notably, southern basins such as Erie and Ontario experienced greater increases in soil moisture during the warm season, suggesting the influence of vegetation growth on soil moisture dynamics. These results emphasize the importance of considering both seasonal and regional variations when assessing climate change impacts on hydroclimate dynamics. While our study focused on temperature and precipitation, the findings highlight the need for future research to explore additional climate factors and their interactions. This comprehensive long-term analysis of hydroclimate trends provides valuable insights for understanding historical hydrological changes and informs the development of sustainable water resource management strategies in the Great Lakes region.

METHODOLOGY
- Model configuration: We employed WRF-Hydro in standalone mode with the Noah-MP land surface model. The hydrological routing options of the steepest descent method and the Muskingum-Cunge method were selected to represent surface overland flow routing and reach-based channel routing, respectively. We used the configuration and calibrated parameter sets of NWM version 2.1 (NWMv2.1) for the WRF-Hydro simulation. 
- Meteorological forcing dataset: We used the fifth-generation European Centre for Medium-Range Weather Forecasts atmospheric reanalysis data (ERA5) to drive WRF-Hydro. ERA5 provides data on precipitation, air temperature, surface pressure, specific humidity, short and long wave radiation, and wind speed (u-, v-direction) with a spatial resolution of 0.25° and a temporal resolution of hourly from 1940 onwards. 
- Spatial inputs: We utilized the subset of NWMv2.1, which employed spatial datasets including digital elevation maps, soil maps, land use, and river networks for model setup (see Data Availability). The hydrofabric dataset for the entire Great Lakes basin, customized by Mason et al. (2019), seamlessly combines hydrographic data from the U.S. and Canada and is incorporated into NWMv2.1. 
- Model setup: The meteorological forcing dataset and spatial inputs were regridded to a 1 km resolution.

SOFTWARE SPECIFICATION
The data are model output from the WRF-Hydro hydrologic model (version 5.2). WRF-Hydro is a numerical hydrologic model written in Fortran. To execute WRF-Hydro, prospective users must download the program's source codes from https://ral.ucar.edu/projects/wrf_hydro/model-code and install the model on a Linux cluster following the instruction on the same website.
The Linux system that WRF-Hydro is installed on must have the NetCDF library installed.

FILES CONTAINED HERE
This dataset includes land surface and hydrological simulations across the entire Great Lakes basin for the 80-year period from 1941 to 2020 using ERA5 forcing. The 16 files are organized into two types of .tar.gz archives, representing 10 years of simulations each, with 3,652 NetCDF files within each archive.
1. Channel Routing Output (CHRTOUT_YYYY_YYYY.tar.gz)
2. Land Surface Output (LDASOUT_YYYY_YYYY.tar.gz)
   Each archive contains daily simulations in NetCDF format. For example:
     Channel Routing Output: 194101010000.CHRTOUT_DOMAIN1
     Land Surface Output: 194101010000.LDASOUT_DOMAIN1
       The naming convention for these files is as follows:
	   YYYYMMDDhhmm.CHRTOUT_DOMAIN1
	   YYYYMMDDhhmm.LDASOUT_DOMAIN1
		 YYYY: Year
		 MM: Month
		 DD: Day
		 hh: Hour
		 mm: Minute
The channel routing output includes streamflow, subsurface flow, and groundwater flux. The land surface output includes variables such as evapotranspiration, snow water equivalent, and soil moisture at four different layers, among other variables.
These are just a few examples of the modeling outputs. For more details about all the WRF-Hydro modeling outputs, refer to Gochis et al. (2020).
Reference
Gochis, D.J., Barlage, M., Dugger, A., FitzGerald, K., Karsten, L., McAllister, M., McCreight, J., Mills, J., RafieeiNasab, A., Read, L. and Sampson, K., 2020. The WRF-Hydro modeling system technical description (Version 5.2). University Corporation for Atmospheric Research: Boulder, CO, USA. 

USE AND ACCESS
This data set is made available under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0).

TO CITE DATA
Shin, S., and Gronewold, A., 2024. Hydrological simulations across the Great Lakes basin from 1941 to 2020 [Data set]. University of Michigan - Deep Blue. https://doi.org/10.7302/wkd1-nb64