Higher Frozen Soil Permeability Represented In A Hydrological Model Improves Spring Streamflow Prediction From River Basin To Continental Scales
Presenter: Mohammad A. Farmani1
Co-Author(s): -
Advisor(s): Dr. Ali Behrangi & Dr. Guo-Yue Niu
1Department of Hydrology and Atmospheric Sciences, University of Arizona
Although there is substantial evidence from laboratory experiments at the pedon scale that frozen ground affects snowmelt infiltration, observations of streamflow at larger scales show a weaker or no effect in terms of timing and magnitude. To better understand this conflicting phenomenon, we conducted 16 experiments using the Noah land surface model with multi-physics options (Noah-MP) and the Routing Application for Parallel computation of Discharge (RAPID) over the Mississippi River Basin (MRB). Our experiments involved combinations of two supercooled liquid water (SLW) parameterization schemes and four soil hydraulic property (SHP) schemes in Noah-MP, driven by two gridded precipitation products: the North American Land Data Assimilation System (NLDAS) and the Integrated Multi-satellite Retrievals for GPM (IMERG) Final. We then used RAPID to route Noah-MP modeled surface runoff and groundwater discharge to predict daily streamflow at 52 USGS gauges from 2015 to 2019. Our findings suggest that a model with the highest permeability performs better than those with lower permeability schemes in predicting daily streamflow by 20%–57% throughout a water year and 29%–113% for spring streamflow, as measured by the mean Kling-Gupta Efficiency of the 52 gauges. Furthermore, our results show that different SLW schemes have negligible effects on streamflow predictions, and that models forced by IMERG perform better than those forced by NLDAS at most gauges. Both precipitation products confirm that a higher permeability scheme yields more accurate streamflow predictions over frozen ground. In future studies, it is recommended to incorporate preferential flows through macropore networks to improve our understanding of the effects of frozen soil on infiltration and discharge across scales.