Dr Taufique Mahmood, of the Global Institute of Water Security and Centre for Hydrology, will present a seminar on
Hydrologic Spatial Patterns in a semiarid Ponderosa Pine hillslopes
on Monday 16 July, 2012, at 2:00pm, in Room 146 Kirk Hall
Ponderosa pine forests are a dominant land cover type in semiarid montane areas. Water supplies in major rivers of the southwestern United States depend on ponderosa pine forests as these ecosystems:
(1) receive a significant amount of rainfall and snowfall,
(2) intercept precipitation and transpire water, and
(3) indirectly influence runoff by impacting the infiltration rate.
However, the hydrologic patterns in these ecosystems with strong seasonality are poorly understood. In this study, we use a distributed hydrologic model to understand hydrologic patterns in a patchy ponderosa pine landscape. Our modeling effort is focused on the hydrologic responses during North American Monsoon (NAM) and winter to summer transitional period.
Our findings indicate that vegetation patterns primarily influence the hillslope hydrologic response during dry summer periods leading to patchiness related to the ponderosa pine stands. The spatial response patterns switch to fine-scale terrain curvature controls during persistently wet NAM periods. Thus, a climatic threshold involving rainfall and weather conditions during the NAM is identified in the hillslope response when sufficient lateral soil moisture fluxes are activated by high rainfall amounts and the lower evapotranspiration induced by cloud cover.
Our findings on the winter to summer transitional period indicate the importance of the relative wetness of each season. For a sequence with a wet winter and a dry summer, a robust snowpack results in abundant soil moisture in the hillslope that persists until the summer season when evapotranspiration consumes it. Under these conditions, the hillslope lateral transport becomes disconnected during the spring transition. We observe an opposite sequence of events when a dry winter is followed by a wet summer period. For each case, the spatial controls on hillslope hydrologic patterns are assessed relative to the terrain and vegetation distributions.
Results from this work have implications on the design of hillslope experiments, the resolution of hillslope scale models, and the prediction of hydrologic conditions in ponderosa pine landscapes. Further, the proposed methodology can be useful for predicting responses to climate and land cover changes that are anticipated for the southwestern United States.

MSc candidate Chris Marsh will present a seminar on
Implications of mountain shading on calculating energy for snowmelt using unstructured triangular meshes

On Thursday June 28, 2012, at 10am, in 146 Kirk Hall
In many parts of the world, snowmelt energy is dominated by solar irradiance. This is the case in the Canadian Rocky Mountains, where clear skies dominate the winter and spring. In mountainous regions, solar irradiance at the snow surface is not only affected by solar angles, atmospheric transmittance, and the slope and aspect of immediate topography, but also by shadows from surrounding terrain. Accumulation of errors in estimating solar irradiation can lead to significant errors in calculating the timing and rate of snowmelt due to the seasonal storage of internal energy in the snowpack. Gridded methods are often used to estimate solar irradiance in complex terrain. These methods work best with high-resolution gridded digital elevation models (DEMs), such as those produced using LiDAR. However, such methods also introduce errors due to the rigid nature of the mesh, creating artefacts and other artificial problems. Unstructured triangular meshes, such as triangulated irregular networks, are more efficient in their use of DEM data than fixed grids when producing solar irradiance information for spatially distributed snowmelt calculations and they do not suffer from the artefact problems of a gridded DEM. This project demonstrates the use of a horizon-shading algorithm model with an unstructured mesh versus standard self-shading algorithms. A systematic over-prediction in irradiance is observed when only self-shadows are considered. This over-prediction can be equivalent to 20% of total pre-melt snow accumulation. The modelled results are diagnosed by comparison to measurements of mountain shadows by time-lapse digital cameras and solar irradiance by a network of radiometers in Marmot Creek Research Basin, Alberta, Canada.

Dr Jessica Lundquist, Associate Professor at the University of Washington, will speak on Cold Air Pools in Complex Terrain, on Tuesday April 10th at 2pm in Agri 2C71.
In complex terrain, air in contact with the ground becomes cooled from radiative energy loss on a calm clear night and, being denser than the free atmosphere at the same elevation, sinks to valley bottoms. Cold-air pooling (CAP) occurs where this cooled air collects on the landscape. We present an objective mapping algorithm for identifying cold-air pool locations and compare the results against distributed temperature measurements in Loch Vale, Rocky Mountain National Park, Colorado; in the Eastern Pyrenees, France; and in Yosemite National Park, Sierra Nevada, California. We then discuss the impacts of cold air pools on snow, hydrology, and ecology, both in the present day and under a changing climate.

The Centre for Hydrology is pleased to present a hydrology seminar by Muluneh Mekonnen, IP3 Post-Doc, from 12:30 to 1:15pm on Friday 7 October 2011, in AGRI 1E69, entitled IP3’s combined top-down and bottom-up modelling approach using MESH and CRHM as complementary modelling platforms
The IP3 (Improving Processes and Parameterization for Prediction in Cold Regions Hydrology) network came to a successful end in September 2011, leaving a legacy of extensive cold regions processes, parameterization and prediction research work.
IP3’s strategic goal was to attain a more comprehensive physical description of cold regions processes and parameterizations, at regional and smaller scales, for improved prediction within hydrological and hydro-meteorological models such as the Cold Regions Hydrological Model (CRHM) and the Community Environmental Hydrology Land-Surface modelling system, known as MESH.
This seminar presents an application of the combined top-down and bottom-up hydrological modelling approach, using MESH and CRHM as complementary modelling platforms, for the South Saskatchewan River Basin (SSRB) and the Upper Assiniboine River Basin (UARB). In addition to cold regions processes, the SSRB and UARB are characterized by the prairie pothole topography that brings in the additional complexity of shrinking and expanding horizontal flow contributing areas.
The seminar will highlight two key points:
1) How to build a model with relatively minimal complexity whose prediction is commensurate with observations, and
2) How to use the Grouped Response Units approach for physically based parameter regionalization.
Feel free to bring your lunch!

Matt MacDonald will be defending his MSc, entitled Hydrological response unit-based blowing snow modelling over mountainous terrain on Monday, 18 October at 1:00 pm, in room 144 Kirk Hall

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Director of the Centre for Hydrology Prof John Pomeroy will be giving a cyber-seminar on Advancing hydrological processes to better predict hydrology in cold regions, for the US Consortium of Universities for the Advancement of Hydrological Science Inc (CUAHSI), at 3 pm Eastern Daylight Time on Friday, 17 September.
The subject-area will cover results from IP3, DRI and other research from the University of Saskatchewan’s Centre for Hydrology.
To attend, browse to http://www.cuahsi.org/sem-current.html#0917.

Bacon & Eggheads Breakfast
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Water prescriptions for a dry land – how the West can prepare for drought

John Pomeroy, University of Saskatchewan

Date: Thursday, May 27, 2010 from 7:30am ‑ 9:00 am
Place: Room 200, West Block, Parliament Hill
Registration deadline: Tuesday, May 25th. Please register by contacting Donna Boag, PAGSE Manager,
email: pagse@rsc.ca, tel: (613) 991‑6369.
Cost: $20. No charge to Members of the House of Commons, Senators and Media.

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The Canadian Rockies Snow and Ice Initiative announces its 2010 Speaker Series! Our first presentation will be Tuesday evening, 26 January, at 7:00 PM in the Canmore Collegiate High School Theatre, Canmore, Alberta. Following the presentation by Dr. John Pomeroy, we will have an audience discussion on “What is the CRSI and what can it mean for Canmore and the Bow Valley?” followed by refreshments and a chance to mingle.
Five additional evening presentations by Canadian and international snow and ice researchers will follow from February to May. You can download the full program here.

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When interesting hydrology seminars will be held at the Centre for Hydrology they will be posted here.

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