HydroEstimator HE Bob Kuligowski Clay Davenport Rod Scofield

Hydro-Estimator (HE) Bob Kuligowski, Clay Davenport, Rod Scofield, Gilberto Vicente NOAA/NESDIS/ORA

Theory / Schematic • Algorithm Inputs (IR, MW, NWP): – 10. 7 -µm IR window Tb’s from GOES-9, -10, -12, Meteosat-5 and -7 – NAM or GFS PW, 1000 -700 h. Pa 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 temperature>213 K – Z=-(Tadj-µT)/σT: rain only where Z>0 – Rain rate=f(Tadj, Z, PW) – Reduce rain rate in low-RH environments

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 ΔTb to improve performance in early stages of convection; work planned for this fall

Algorithm Output Information • Spatial Resolution: 4 km Western Hemisphere, 6 km elsewhere • Spatial Coverage: global (60°S – 60°N) • 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/emb/ff/auto. html – (digital) ftp: //www. orbit. nesdis. noaa. gov/pub/smcd/emb/f_f/hydroest/worl d/world/

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)