Intercomparison of Multiple Hydroclimatic Datasets across the Lower Nelson River Basin, Manitoba, Canada

Abstract

This study evaluates the 1981-2010 spatiotemporal differences in six available climate datasets (daily total precipitation and mean air temperature) over the Lower Nelson River Basin (LNRB) in ten of its sub-watersheds at seasonal and annual time scales. We find that the Australian National University spline interpolation (ANUSPLIN), and inverse distance weighted (IDW) interpolated observations from 14 Environment and Climate Change Canada (ECCC) meteorological stations show dry biases, whereas reanalysis products tend to overestimate precipitation across most of the basin. All datasets exhibit prominent disagreement in precipitation trends whereby the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-Interim) and European Union Water and Global Change (WATCH) Forcing Data ERA-Interim (WFDEI) show exceptional wetting trends, while the IDW and ANUSPLIN data manifest drying trends. Mean air temperature trends generally agree across most of the datasets; however, the North American Regional Reanalysis (NARR) and IDW show stronger warming relative to other datasets. Overall, analyses of the different climate datasets and their ensemble reveal that the choice of input dataset plays a crucial role in the accurate estimation of historical climatic conditions, particularly when assessing trends, for the LNRB. Using the ensemble has the distinct advantage of preserving the unique strengths of all datasets and affords the opportunity to estimate the uncertainty for hydrologic modelling and climate change impact studies. RÉSUMÉ [Traduit par la rédaction] Cette étude évalue les différences, dans le temps et dans l'espace, de six séries de données climatologiques enregistrées de 1981 à 2010 (précipitations quotidiennes totales et température moyenne de l'air) sur le bassin inférieur du fleuve Nelson dans dix de ses sous-bassins versants, et ce, à des échelles saisonnière et annuelle. Nous constatons que l'interpolation par la fonction spline de l'Australian National University (ANUSPLIN) et les observations interpolées pondérées inversement à la distance (IDW) issues de 14 stations météorologiques d'Environnement et Changement climatique Canada présentent des biais secs, tandis que les produits de réanalyse ont tendance à surestimer les précipitations sur la presque totalité du bassin. Toutes les séries de données présentent des désaccords marqués quant aux tendances des précipitations. Les données provisoires du Centre européen pour les prévisions météorologiques à moyen terme (ERA-Interim du CEPMMT) et les données de forçage du projet Water and Global Change (WATCH-Forcing-Data-ERA-Interim) de l'Union européenne montrent des tendances humides exceptionnelles, tandis que les données issues de l'IDW et de l'ANUSPLIN révèlent des tendances sèches. Les tendances des températures moyennes de l'air concordent généralement d'une série de données à l'autre. Toutefois, la réanalyse régionale nord-américaine (NARR) et l'IDW montrent un réchauffement plus marqué par rapport aux autres séries de données...

Sensitivity analysis and uncertainty assessment in water budgets simulated by the variable infiltration capacity model for Canadian subarctic watersheds

“…The negative (positive) biases from IDW VIC, ANUSPLIN VIC, and HydroGFD VIC (ERA‐I VIC and WFDEI VIC) contribute to the lower NSE and KGE coefficients, whereas the timing of seasonal flows resembles the observed flows in the IDW VIC and ANUSPLIN VIC. The ERA‐I VIC and WFDEI VIC simulations reveal strong positive biases for most of the sub‐watersheds due to their wet biases in the precipitation data sets (Lilhare et al, ); however, they show acceptable NSE and KGE coefficients (≥0.5) for most of the sub‐basins.…”

“…These data sets are assembled to produce the Ensemble data set from 1981 to 2010. Our companion paper (Lilhare et al, ) and Text S1 provide a comprehensive intercomparison and additional details of these data sets. The NARR, ERA‐I, and HydroGFD daily precipitation and wind speed are obtained from the sum and average of 3‐hourly values for a 24‐hr period, respectively.…”

“…We use a split sample approach to span the variety of relatively dry/wet/warm/cool years. Years 1981–1985 (dry/cool) and 1995–1999 (wet/warm) are used for calibration, and 1986–1994 (average) forms the validation period (Table ; Lilhare et al, ). The MOCOM‐UA optimizer searches a group of VIC input parameters using the population method; it attempts to maximize the NSE coefficient between observed and simulated streamflow at each iteration.…”

“…This diminishes simulation uncertainty in the calibration, validation, and water balance estimation during the study period. Intercomparison of the seven meteorological data sets from our companion paper suggests that the Ensemble data set provides more robust historical meteorological forcing (Lilhare et al, ); therefore, the VIC model forced by the Ensemble data set (i.e., Ensemble VIC) is used as a reference calibration simulation to investigate the propagated uncertainties in water balance estimation from different input forcing data sets.…”

“…In this study, we quantify the uncertainty propagated from available forcing data sets in their surface water balance estimations over the lower Nelson River Basin (LNRB) in northern Manitoba, Canada. To achieve this goal, seven input forcing data sets that are intercompared in our companion paper are ingested into the VIC model over the LNRB (Lilhare, Déry, Pokorny, Stadnyk, & Koenig, ). These data sets are used in various other studies over different Canadian regions (Boucher & Best, ; Islam & Déry, ; Sauchyn, Vanstone, & Perez‐Valdivia, ; Seager et al, ; Woo & Thorne, ).…”