Essery, Richard

Moncrieff, John

MacDonald, Matthew Kenneth

other

2017-02-08T15:25:54Z

2017-02-08T15:25:54Z

2016-06-27

The South Saskatchewan River Basin (SSRB) is amongst the largest watersheds in Canada. It is an ecologically diverse region, containing Montane Cordillera, Boreal Plains and Prairie ecozones. The SSRB is subject to chinooks, which bring strong winds, high temperatures and humidity deficits that alter the storage of water during winter. Approximately 40% of winter days experience chinooks. Ablation during chinooks has not been quantified; it is not known how much water evaporates, infiltrates or runs off. The aim of this thesis is to characterise the spatial variability of surface water fluxes as affected by chinooks over SSRB subbasins and ecozones. The objectives are addressed using detailed field observations and physically based land surface modelling. Eddy covariance was deployed at three prairie sites. During winter chinooks, energy for large evaporative fluxes were provided by downward sensible heat fluxes. There was no evidence of infiltration until March. The Canadian Land Surface Scheme (CLASS) coupled to the Prairie Blowing Snow Model (PBSM) was used as the modelling platform. A multi-physics version of CLASSPBSM was developed, consisting of two parameterisation options each for sixteen processes. Field observations were used to evaluate each of the configurations. Three parameterisations provide both best snow and best soil water simulations: iterative energy balance solution, air temperature and wind speed based fresh snow density and de Vries’ soil thermal conductivity. The model evaluation highlighted difficulties simulating evaporation and uncertainty in simulating infiltration into frozen soils at large scales. A single model configuration is selected for modelling the SSRB. Modelling showed that the SSRB generally experiences no net soil water storage change until March, confirming field observations. Chinooks generally reduce net terrestrial water storage, largely due to snowmelt and subsequent evaporation and runoff. The Prairie ecozone is that which is most strongly affected by chinooks. The Montane Cordillera ecozone is affected differently by chinooks; blowing snow transport increases during winter and runoff increases during spring. The Lower South Saskatchewan is the subbasin most affected by chinooks. The Red Deer is the subbasin least affected by chinooks.

http://hdl.handle.net/1842/19561

en

The University of Edinburgh

Fang, X.F., Pomeroy, J.W., Ellis, C.R., MacDonald, M.K., DeBeer, C.M., Brown, T.: Multi-variable evaluation of hydrological model predictions for headwater basin in the Canadian Rocky Mountains. Hydrol. Earth Syst. Sci., 17, 1635-1659, 2013.

MacDonald, M.K., Pomeroy J.W. & Pietroniro, A.: On the importance of sublimation to an alpine snow mass balance in the Canadian Rocky Mountains. Hydrol. Earth Syst. Sci., 14, 1401-1415, 2010.

MacDonald, M.K.: Hydrological response unit-based blowing snow modelling over mountainous terrain, M.Sc. thesis, Centre for Hydrology, University of Saskatchewan, Canada, ADA 044002, 2010.

chinook

land surface scheme

eddy covariance

hydrometeorology

snow

model

evaporation

chinook

land surface scheme

eddy covariance

hydrometeorology

snow

model

evaporation

Global Change Research Institute

Hydrometeorological response to chinook winds in the South Saskatchewan River Basin.

Thesis or Dissertation

Doctoral

PhD Doctor of Philosophy