Bob Kuligowski, Clay Davenport, Rod Scofield, Gilberto Vicente 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 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 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/world/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)