GangesBrahmaputra Catchments

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Ganges-Brahmaputra Catchments
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ECMWF Seasonal Model

• IFS atmosphere GCM T95 w/ 1.8deg Gaussian grid,
  40 vertical levels, 1hr time-step
• HOPE OGCM zonal grid spacing 1.4deg, meridional
  spacing 0.3 near equ to 1.4 in mid-lat, 29
  vertical levels, 1hr time-step
• Coupling (flux exchange) done using version of
  OASIS, done once/day (atm driven by SST and
  sea-ice ocean with heat/moisture/momentum fluxes)

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2003 GPCP/EMCWF(ensemblemean) Comparisons
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2003 Ganges Catchment-avg precip comparisons
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2003 Brahmaputra Catchment-avg precip comparisons
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"Dressing" seasonal forecasts

• Forced accumulated ensemble mean precip to match
  "observed"
• Generated forecasts within "model space" gt
  quantile-to-quantile mapping
• BEST single scale factor applied to each
  forecast horizon/each month
• FUTURE 1) MM5 downscaling 2) more sophisticated
  MOS-type techniques

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"Dressed" Precipitation Results
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"Dressed" Discharge Results
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2004 Discharge Forecasts
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2004 Forecast Histograms