HydroEstimator HE

1
Hydro-Estimator (HE)

• Bob Kuligowski, Clay Davenport, Rod Scofield,
  Gilberto Vicente
• NOAA/NESDIS/ORA

2
Theory / Schematic

• Algorithm Inputs (IR, MW, NWP)
• 10.7-µm IR window Tbs from GOES-9, -10, -12,
  Meteosat-5 and -7
• NAM or GFS PW, 1000-700 hPa mean RH, u, v,
  convective EL computed from T, q profile
• Satellite inputs are from GVAR feeds model
  inputs come from NCEP
• Algorithm Process (how the inputs are converted
  to rainfall estimates)
• Adjust Tb (Tadj) by reducing values where
  convective EL temperaturegt213 K
• Z-(Tadj-µT)/sT rain only where Zgt0
• Rain ratef(Tadj, Z, PW)
• Reduce rain rate in low-RH environments

3
Theory / Schematic

• Strengths and Weaknesses of Underlying
  Assumptions
• Standard IR assumption that Tb is a proxy for
  cloud depth / updraft strength and hence for rain
  rate works best for convective precipitation
• Assumes rainfall only in areas of positive Z
  (local Tb minima) effective screening of cirrus
  by using Z
• Adjusts for environments with low convective EL
  by adjusting Tb downward based on convective EL
  temperature, but still underestimates warm-cloud
  rainfall
• Underestimates rainfall early in convective life
  cycle where updrafts are strong and clouds are
  rapidly cooling, but still relatively warm
• Planned Modifications / Improvements
• Currently undergoing recalibration using 6 weeks
  of CONUS data from summer 2003 with bias-adjusted
  radar as target data should be completed by end
  of summer
• Inclusion of Lagrangian ?Tb to improve
  performance in early stages of convection work
  planned for this fall

4
Algorithm Output Information

• Spatial Resolution 4 km Western Hemisphere, 6 km
  elsewhere
• Spatial Coverage global (60S 60N)
• Update Frequency same as IR update frequency
• 15 min over CONUS
• Generally 30 min elsewhere, but up to 3 h in
  parts of Southern Hemisphere
• Data Latency 10 min after data received at ORA
• Source of Real-Time Data
• (graphic) http//www.orbit.nesdis.noaa.gov/smcd/em
  b/ff/auto.html
• (digital) ftp//www.orbit.nesdis.noaa.gov/pub/smcd
  /emb/f_f/hydroest/world/world/

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Algorithm Output Information

• Source of Archive Data
• limited online archive at real-time ftp site
• offline global archive back to 25 May 2005
• offline CONUS archive back to April 2003
• Capability of Producing Retrospective Data (data
  and resources required / available)
• CONUS tape archive of component files back to
  1997
• Northern Hemisphere can get GOES IR data from
  CLASS (back to December 2003) and use archive Eta
  adjustment files
• Elsewhere need 10.7-µm data and AVN/GFS fields
  (PW, RH, T, u, v)