Improving Processes & Parameterization
for Prediction in Cold Regions Hydrology
Centre for Hydrology, University of Saskatchewan,
Saskatoon, Saskatchewan, Canada
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Centre for Hydrology

Theme 3 - Prediction

Theme Lead: Alain Pietroniro, University of Saskatchewan and Environment Canada
(e-mail, www)

The objective of Theme 3 is to test and improve weather, water, and climate models leading to enhanced prediction and simulation of related atmospheric impacts on water resources, atmospheric fluxes, and surface climates in cold regions.

The theme aims to achieve this goal through a combination of observational, experimental, theoretical, and modelling studies at a range of appropriate spatial and temporal scales developed in Theme 1 and Theme 2.

The IP3 approach combines the strength of bottom-up (deductive reasoning from point-scale process relationships, or 'microscale studies') and top-down (inductive reasoning from large-scale basin behaviour, or 'mesoscale modelling') modelling methods. These two methods meet conceptually in the middle, through definition of the Hydrological Response Units (HRUs) described in Theme 2.

By combining land surface hydrology models, regional atmospheric models, numerical weather prediction models, and coupled environmental models, we are able to examine the influence of varying land cover and boundary atmospheric conditions at multiple scales, from local to regional (10s of km to 1000s of km). This approach is resulting in improvements to water resource modelling capability, providing better modelling structure, more coprehensive physical description, and therefore improved parameterisation. Particular areas of improvement include representation of the interaction of soil moisture and evaporation, optimisation of land-surface parameters using streamflow hydrographs, and the parameterisation of cold region processes including permafrost, frozen soil, snow sublimation, and snow redistribution by wind and vegetation.

IP3's 'strategic' model is based on a configuration of Environment Canada's Modélisation Environmentale Communautaire (MEC), a 'community environmental modelling system' which facilitates integration between individual models representing different components of the earth system. The configuration used by IP3, MEC - Surface and Hydrology (MESH), couples independent hydrological and atmospheric models, so that modelled land-surface hydrological behaviour influences and reacts to the atmosphere just as weather and water co-exist in the natural world. New components (including new parameterisations) which are to be incorporated into MESH and the other predictive models are tested by comparing simulation results to as many other datasets as possible. These may be field measurements, or the results of more local models, such as very fine scale finite element models, or CRHM.

Modelling domains have been established at three different scales for western Canada, with each being represented by a different predictive model.

The CRCM domain is established over all of western Canada (thick black line);
GEM-north and GEM-south are established over the CRCM domain (thin black lines);
MESH domains focus on the eight research basins (red circles)

Regional Resolution
The Canadian Regional Climate Model (CRCM) is being used to provide synthetic climate data over western Canada. The CRCM is a numerical integration scheme for computing atmospheric flow and is generally used at large spatial scales and coarse resolution. It is very useful for examining the regional impacts of climate change and variability.

Intermediate Resolution
The Global Environmental Multiscale (GEM) model, currently used at Environment Canada for numerical weather prediction such as weather forecasting, is being run as a Limited Area Model (GEM-LAM) over two domains, GEM-North and GEM-South. GEM-LAM operates at intermediate resolution and thus bridges regional simulations from CRCM and basin-scale simulations from MESH.

Basin-Level Resolution
MESH has been established and is being run over all eight IP3 basins at increasingly high resolutions. As described above, MESH combines atmospheric modelling with land-surface and hydrological modelling. These predictive models are designed to be used in both hindcasting and forecasting modes.

The two other models in the IP3 modelling hierarchy are CRHM and CLASS.

The Cold Regions Hydrological Model (CRHM) is being used as a method to test parameterisations, which may then be improved and incorporated into the larger-scale predictive models, GEM and MESH; it is also a predictive tool in its own right. The simple user interface of CRHM makes it useful for training and for development of purpose-built physically-based basin models which rely on zero or minimal calibration. CRHM is available to all interested users as a technology transfer component to IP3.

The Canadian Land Surface Scheme (CLASS) is used as either a stand-alone land surface scheme or as part of the MESH, GEM, and CRCM models. The current versions of CLASS and MESH have not been widely tested in complex topography or cold regions, so it is IP3's mandate to evaluate and improve these models for operational applications in Canada.

IP3 Collaborator James Craig is involved in the Environmental Modelling and Analysis Group at the University of Waterloo. His work focuses on numerical and semi-analytical approaches for modelling surface and groundwater flow.

Further details are available from the IP3 Models page.

Theme 3 Timeline:

Operational version of existing MESH model established for all research basin and NWP domains

  • Review current modeling and data status in meso-scale and regional research basins
  • This would include establishing GEM-LAM domains for each of the research domains that incorporate the MESH system for hydrological routing and basin segmentation (tiles, tile connectors and grid connectors)
  • These simulations will be based on existing Water Survey of Canada and exiting climate and synoptic stations gauge locations within the domain

Incorporate new process and possible parameterisations into the MESH system

  • Establish and evaluate water and cycle predictions derived from the MESH modelling domains using primarily the CLASS land surface model and existing routing models
  • Perform sensitivity analysis of atmospheric fluxes and prognostic predictions, as well as through comparison with observed hydrographs. Where possible, the model predictions will be compared with key variables such as discharge, surface water storage, water balance, snowcover, soil moisture, soil frost, soil heat flux, evaporation

On-going improvements of MESH with new algorithms on each research basin, and evaluate model performance with reference to measured mass and energy balances

  • Re-evaluate regional hydrological response based on improved parameterization from research basins and IP3 field studies
  • The prediction team will work closely with the research teams in P1 and P2 to evaluate the relative importance, sensitivity and cumulative effect of introducing algorithms, parameterizations and new landscape segmentations derived through field and basin experiments.

Evaluate performance of coupled models for major cold regions land covers

  • This will include incorporating cryospheric process numerical descriptions into land surface schemes coupled to a hydrological model to produce a coupled modelling system that will provide a comprehensive simulation of the terrestrial cryospheric system and its interaction with hydrology and the atmosphere
  • Simulate terrestrial water and energy cycles for the selected cold regions environments 

Theme 3 Deliverables
It is anticipated that by the end of year 4, the following deliverables will have been derived:

  • Integrated hydrology-land surface model (MESH). IP3 program will have assessed the feasibility, scientific and technical considerations required for implementation of the MESH system within the NWP modelling framework of Environment Canada. Because IP3 researchers will be developing MESH within the existing EC modelling framework, all IP3 work will be easily transferable to operational model runs at a later date if so desired by CMC
  • Improved Prediction in Ungauged Regions. Uncertainty in hydrological prediction in ungauged regions is largely due to the impossibility of parameterising models using gauged streamflow. IP3 will improve our understanding in high latitude and altitude regions and use landscape-based parameters resulting from detailed field studies rather than the traditional top-down approaches. Landscape based parameterization will allow rigorous methods of parameter selection and transferability, previously unattainable in most hydrological modelling systems
  • Improved Weather Prediction. It is well understood that feedback from the land-surface to the atmosphere can be a critical control in local weather phenomenon, however assessing the magnitude and importance of land-surface feedbacks is still poorly understood. IP3 will provide the definitive assessment in cold regions and will be the first systematic attempt to quantify the importance of land-surface feedback in cold-regions



Bruce Davison Environment Canada
Richard Essery University of Edinburgh, UK
Vincent Fortin Environment Canada
Murray Mackay Environment Canada
Alain Pietroniro University of Saskatchewan
John Pomeroy University of Saskatchewan
Ken Snelgrove Memorial University of Newfoundland
Ric Soulis University of Waterloo
Chris Spence University of Saskatchewan
Diana Verseghy University of Waterloo