ENHANCED NOWCASTING OF EXTREME WEATHER

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ENHANCED NOWCASTING OF EXTREME WEATHER

• The setup of the WATFLOOD Distributed Hydrologic
  Model over the McGill Radar Coverage

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• Year 2 Hydrological Evaluation Carry out the
  initial assimilation of radar data into
  hydrological models for sensitivity tests of
  various radar algorithms.
• Year 3 Modelling Carry out verification
  experiments with precipitation estimates from
  radar data and NWP in hydrological models.

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These algorithms are
C3 is achieved by integrating the best estimate
of the 5-minute (i.e., instantaneous) surface
precipitation rates obtained by avoiding the
bright band and other radar artifacts. A VPR
correction is applied when higher altitudes are
needed in order to avoid the bright band.
However, the lowest possible scan is used. C3
maps extend only up to 120 km.
VPR vertical profile of reflectivity
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Chateauguay
Study Area
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Watershed details for initial WATFLOOD setup
Flow data for 8 flow stations are e-mailed to us
every 2 weeks by the Raisin River and South
Nation Conservation Authorities
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11 Quebec rivers
There are an additional 83 stations in the US
with flow data on web sites.
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Water System Modeling
Evapotranspiration
Interception
Depression Storage
Wetting Front
Unsaturated Zone
API
Saturated Zone
Channel Flow
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Land cover data base
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Parameters are for land cover classes A, B, c
D Parameters do not change with percentage of
each land cover Each grid has is represented by
a watershed with its own cover allocation.
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Castor R.
S. Nation R.
Raisin R.
Urban Bare Low crops Woodland??? Wetland Dec
. Forest Conf. Forest Water
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Wetland model
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All watershed delineation and data editing
is done with ENSIM-HYDROLOGIC
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Progress to date

• Archived hourly precipitation data from the
  McGill and Franktown Radars since Dec. 5. 2001
  (Up to 7 data streams)
• Archived streamflow and temperature data within
  the study area (Mostly from web sites)
• Set up the WATFLOOD model for all gauged
  watersheds within the McGill radar coverage in
  Ontario, Quebec and the US.
• Calibrated the South Nation and Raisin River
  Conservation Authorities rivers in Ontatrio and
  compared the radar products.

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Hydrology primer

• Hydrological models need at least a seasonal
  spin-up period. For current study, a full
  winters worth of data is OK.
• Most winter and summer flows result from ground
  water (base flow). Ground water is replenished
  mostly during the snowmelt period.
• Most summer runoff (streamflow) is added to this
  base flow.
• A continuous simulation also provides for a good
  estimate of soil moisture at the onset of an
  extreme event. (Need UZS API)

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First of all, weird things can and DO happen
Comparison of Observed and Simulated Snow (on the
ground) Depths, McGill radar data, 2 km
resolution, correction level 2
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Scaled 2X Dec - Mar, 1.5X April
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Summary

• The WATFLOOD model has been configured for the
  watersheds covered by the McGill radar.
• The main interest in using the model during the
  winter of 2002 was to have a properly initiated
  model for the spring.
• The results during late April after the snow
  disappeared are a good start and the simulation
  shows there are differences between the various
  radar products.

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Summary - continued

• In general, based on these very preliminary
  results the impression is that the VPR corrected
  data provide the best estimate of precipitation.
• The WATFLOOD model can now be considered as
  initialized for warmer months of 2002.
• Report available in http//www.watflood.ca

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How do I know WATFLOOD works??
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Check Soil moisture
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Check evaporation
Evaporation comparison for the BOREAS SSA-OBS
Tower Site
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Check evaporation
Evaporation comparison for the BOREAS NSA-OBS
Tower Site
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Check snow course data
Comparison of observed SWE to modelled SWE for
for the Columbia River basin. (Janet Wong, BCH)
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Check snow pillow data
Comparison of snow pillow data and WATFLOOD/SPL
SWE estimates (Janet Wong, BCH)
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Allyson Bingeman
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Heavy precipitation in the Toce - Ticino
watersheds during the MAP IOP 2
MC2 6 hour precipitation forecast
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Sensitivity to storm location