ABSTRACT: Advances in quantitative precipitation estimation for streamflow modelling in Ontario, Canada

CGRG Bibliography of Canadian Geomorphology
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The state of hydrometeorological science and technology continues to advance. Hydrologists have witnessed developments in remote sensing technology and their adoption into hydrological practice. This presentation will focus on advances in observing precipitation through Doppler radar and their use in hydrological modelling. The use of such tools may lead to improved accuracy in the estimation and short term forecasting of streamflow conditions. Such potential improvements could also lead to an expansion of the capacity of information systems in hydrology and could have implications in the future design of ground-based hydrological networks. Within this effort, precipitation fields are estimated using a portion of Environment Canada’s Doppler weather radar network. Environment Canada is midway through a project to upgrade its network of C-band Doppler weather radars. Fifteen radars have been installed or upgraded and by 2004, a complete network of thirty radars will provide coverage for approximately ninety-five percent of the population of Canada. The main focus of these systems is to improve the forecasting of severe weather. Suites of radar products are being developed and various efforts are underway to increase their utility in estimating rainfall intensity and its areal distribution. Use of C-band radar poses unique problems which require novel approaches to obtain accurate precipitation fields. Evolving capabilities and approaches represented within the Unified Radar Processing System are used with a distributed hydrological model to evaluate performance. Estimated flow values from a distributed hydrological model, WATFLOOD, set up over selected pilot basins are compared to estimated flows from hydrometric gauges representing drainage areas ranging from 100 km2 to 3500 km2. WATFLOOD is a grid-based model developed by the University of Waterloo, Ontario. The model characterizes watersheds by using high resolution LANDSAT images to identify various hydrologically similar land types which are subsequently grouped within each hydrological model grid cell to create grouped response units (GRU’s). This presentation focuses on results to date over one watershed in Southern Ontario that is within range and roughly equidistant from two C-band Doppler radars. The pilot study covers a 100-day period during summer 2000 when several intense rainfall events were known to have occurred. These provide an opportunity to quantify the effects of radar beam attenuation and other artifacts on estimating precipitation fields through the use of a distributed hydrological model.

Bibliography of Canadian Geomorphology