Hydrological modeling of freshwater discharge into Hudson Bay using HYPE

Abstract

Introduction The Hudson Bay Drainage Basin (HBDB) comprises over a third of the Canadian landmass, contains important hydroelectric infrastructure and agricultural lands, and accounts for over a fifth of freshwater exports into the pan-arctic ocean system via the Hudson Bay Complex (HBC comprised of Hudson Bay, James Bay, Ungava Bay, Foxe Basin, and Hudson Strait; McClelland et al., 2006). The HBC itself is important to Arctic marine wildlife, and as a shipping route for Canada. It is a large region of primary production, influenced mainly by the timing of freshwater inputs (largely meltwater). Changing freshwater inputs are essential to the annual formation, decay and break up of sea ice, with seasonal ice cover being important for the HBC pelagic life (Manak and Mysak, 1989; Saucier et al. 1998, 2004). HBDB terrestrial discharge influences Arctic Ocean circulation, sea ice dynamics, biological and biogeochemical processes within the HBC. Due to the importance of terrestrial freshwater fluxes into the HBC for bay-wide circulation and ice-formation, continental-scale hydrologic modeling is key to the combined modeling/observation BaySys group of projects (Barber, 2014). The importance of the HBDB necessitates a comprehensive hydrological monitoring and prediction framework. Although hydrometric gauges remain relatively dense in southern, lower-latitude regions of the basin, higher-latitude counterparts remain poorly gauged. Additionally, the number of hydrometric gauges has declined across Canada in recent decades (Coulibaly et al., 2013; Mlynowski et al., 2011). As of 2013, 40% of the HBDB is ungauged and 27% has never been gauged. Hydrological modeling is required to fill spatial and temporal gaps in the observational record, and for making long-term streamflow projections. Over the same period this basin has undergone significant climate change impacting the distribution and

Changing freshwater contributions to the Arctic

“…The A-HYPE implementation covers 23 million km 2 of the global continental landmass draining poleward, toward the Arctic Ocean, divided into 32,599 subbasins with approximately 700 km 2 horizontal resolution. For this research, a modified version of the model was generated by the University of Calgary Hydrologic Analysis Laboratory that included improved lake calibration, a frozen soil routine, and a regulation (reservoir) model for the HBDB (Stadnyk et al, 2020). This revised implementation of A-HYPE was used to generate daily streamflow for the pan-Arctic domain (Figure 1), driven by the HydroGFDv2 reanalysis.…”

“…As part of the BaySys project, a new configuration and recalibration of the A-HYPE model was conducted for the HBDB and is summarized in Stadnyk et al (2020). River regulation, frozen soil processes, and lake routing were revised within the Canadian domain (Stadnyk et al, 2020), which is utilized in this study as well. Here, we evaluated model performance across the pan-Arctic domain using daily discharge aggregated to a monthly timescale where we computed statistics for our 75 validation gauges.…”

A baseline evaluation of atmospheric and river discharge conditions in the Hudson Bay Complex during 2016–2018

“…Terrestrial (overland) precipitation and temperature, used as input to the BaySys Team 2 Hudson-HYdrological Predictions for the Environment (H-HYPE; Andersson et al, 2015;Stadnyk et al, 2020) hydrological model, are investigated using the Hydrological Global Forcing Data product (HydroGFDv2, 0.5 grid; Berg et al, 2018) over the HBW. HydroGFD is an updated and extended version of the Watch Forcing Data-ERA-Interim method; although both use ERA-Interim, HydroGFD enables other reanalysis products to replace the ERA-Interim reanalysis to allow for correction in bias in temperature and precipitation.…”

Canadian Continental-Scale Hydrology under a Changing Climate: A Review

“…Under the BaySys project, a custom implementation of the Hydrological Predictions for the Environment (HYPE) model was established for the Hudson Bay basin that incorporated prairie potholes, frozen soils, lake parameterizations, and regulation including dams and diversions [32]. To improve model evaluation, gap-filled, outlet-based observational discharge data records were derived for all rivers entering Hudson Bay [25].…”