Testing and Upcoming Implementation of the 20km RUC Stan Benjamin NOAA / FSL Georg Grell Steve Weygandt Tracy Lorraine Smith Tanya Smirnova Barry Schwartz Dongsoo Kim Dezso Devenyi Kevin Brundage John M. Brown Geoff Manikin – NCEP/EMC Ralph Petersen – NCEP/EMC NCEP Production Suite Review 11 December 01 – updated 15 Feb 02

2 Key goals for 20km RUC Focus on improving RUC performance for QPF, especially for convective precipitation Surface forecasts Cloud/icing 3-d fields Take advantage of increased computer power 40 km / 40 levels  20 km / 50 levels Improved physical parameterizations (cumulus, explicit cloud, land-surface), vertical advection Improved analysis in native  coordinate, cloud analysis

3 RUC20 Testing Since May 2001  Ongoing real-time 1-h cycle at FSL and NCEP  Retrospective period tests – full 1-h cycle  Feb 2001 at NCEP and FSL  July 2001 at NCEP  May 2000 at FSL  Examination of verification against  precipitation, radar  surface observations  rawinsonde observations  Web page products – daily look at maps  For both RUC20/40 analyses and forecasts

4 RUC20 Implementation schedule  CAFTI information items - March, Sept, Nov 2001, Feb 2002  Complete retrospective tests  Feb 2001 – cold season - complete  July 2001 – warm season – almost complete  Real-time tests – late Feb - March 2002  CAFTI approval – late March 2002  Operational implementation – 9 April 2002

5 Subset of full domain 20km RUC 40km RUC Model terrain elevation

6 Subset of full domain 20km RUC 40km RUC Model terrain elevation

7 40km RUC 40 levels 20km RUC 50 levels 10 new levels 7 – upper levels – 330 – 500 K 3 – lower levels – 270 – 290 K RUC native coordinate levels W-E vertical cross-section - Pacific – w. coast 6h fcsts valid 0000 UTC 24 Feb

8 Current Operations – RUC40 RUC20 Resolution40 km, 40  levels20 km, 50  levels AnalysisOptimal interpolation onModified OI technique on generalized on generalized  surfaces  surfaces, hydrometeor analysis w/ GOES…, use raw instead of interp. obs AssimilationIntermittent 1-h cycleIntermittent 1-h cycle Stable cloudsMixed-phase cloud microphysics MM5),New version of MM5/RUC / precipitation explicit fcst of cloud water, rain water, microphysics (FSL and NCAR), snow, ice, graupel, much shorter microphysics time step, no. concentration of ice particles less graupel, more supercooled liq water Sub-grid-scaleGrell (1993)New Grell scheme w/ ensemble cloud, precipitation shallow convection, detrainment of cloud water to microphysics TurbulenceBurk-Thompson explicit TKE schemeModified Burk-Thompson RadiationMM5 LW/SW scheme, f(hydrometeors)MM5 scheme with fix to SW lag error Land-sfc processes6-level soil/veg model (Smirnova, Improved soil model, 2-layer snow model, 1997, 2000) w/ frozen soil, 1-layer snow improved cold season processes, improved diurnal cycle Sfc conditionsDaily RTG_SST (same as Eta),High-res USGS land-use, CONUS soil type, daily NESDIS snow/ice (same as Eta), albedo 0.14  monthly NDVI veg frac (same as Eta), cycled soil moisture/temp, snow depth/temp Lat boundary conds Eta model initialized every 12hEta model initialized every 6h Rapid Update Cycle – Present and Next Version

9 Key RUC20 Modifications Since May Forecast model - revisions to Grell ensemble convective parameterization - use of GOES cloud-data to prompt convective initiation - revised vertical advection / hybrid isentropic-sigma coordinate movement Prompted by PC Spring Program evaluation, model stability - Analysis - 3dVAR found to give slightly poorer wind forecast for 3h period (not at 12h) - Decision made to introduce OI analysis within 3dVAR framework, defer 3dVAR analysis implementation for ~3 months after RUC20 impl. Prompted by FAA use of RUC for Free Flight

Data Type~NumberFreq. Rawinsonde (inc. special obs) 80/12h NOAA 405 MHz profilers 31/ 1h Boundary-layer (915 MHz) profilers ~24/ 1h* VAD winds (WSR-88D radars) / 1h Aircraft (ACARS) (V,temp) / 1h Surface/METAR - land (V,p sfc,T,T d ) / 1h Buoy / 1h GOES precipitable water / 1h GOES cloud drift winds / 1h GOES cloud-top pressure ~40km res / 1h SSM/I precipitable water / 6h GPS precipitable water ~80  / 1h * Ship reports 10s/ 3h Reconnaissance dropwinsonde a few/ variable Data for 20-km RUC at NCEP New for 20km RUC at NCEP Availability pending

11 Improved use of obs in RUC20 analysis More accurate forward models -- simulate observations from background forecast as closely as possible 2m T/q, 10m winds from METARs, buoys Use of background grid-point with matching land-use for coastal stations instead of bilinear interpolation to ob location Account for elevation differences (model vs. ob) for precipitable water Better handling for near-surface raob structure Lapse rate effects – top-down, bottom-up checks - improves analysis boundary-layer temp structure

12 obs 20km – mod OI 1200 UTC 9 Dec 2001 Grand Junction, CO rawinsonde Comparison of obs sounding vs. grid point soundings for RUC40 vs. RUC20 Better near-surface fit to obs with RUC20 40km - OI

13 Initial RUC cloud analysis technique Combines GOES/NESDIS cloud-top pressure (sounder single field-of-view) RUC 1-h hydrometeor fcst (cloud water, ice, snow/rain/graupel) as first guess Performs cloud clearing and cloud building Rederives cloud-top pressure using RUC 1-h fcst sounding / skin temp if NESDIS original value is > 620 mb Goal – Improve RUC precipitation, cloud, icing forecasts

14 Processes in RUC/MM5 microphysics (Reisner, Rasmusssen, Bruintjes, 1998, QJRMS)

15 Verification Cloud-top pressure based on NESDIS product Effect of GOES data on 3-h RUC cloud-top fcsts Valid 1200 UTC 9 Dec h 20km RUC cloud-top fcst w/ GOES cloud assimilation 3h 40km RUC cloud-top fcst No GOES cloud assimilation

16 3h 20km RUC cloud-top fcst w/ GOES cloud assimilation Verification Cloud-top pressure based on NESDIS product Cloud-top forecast verification - correlation coefficient between forecast and NESDIS cloud-top product - much improved cloud forecasts even at 12h 28 Sept – 2 Oct km RUC 20km RUC w/ cloud analysis

17 Key changes in 20km RUC forecast model for QPF 20km/50 level resolution – resolved precipitation improved – grid volumes are now ~5 times smaller Cloud microphysics time step much smaller  2 min Revised hybrid coordinate definition, vertical regridding for all variables Bug fixes in interface between Grell scheme and rest of model New ensemble cumulus parameterization – Grell Revised version of MM5/RUC microphysics

18 Purpose – Improve near-surface, precipitation, cloud forecasts Ongoing cycle of soil moisture, soil temp, snow cover/depth/temp) RUC Land-surface Process Parameterization New in 20km - change in thermal conductivity – better diurnal cycle - frozen soil physics, 2-layer snow model, high resolution land-use, soil type data 40km 20km

19 Changes to MM5/RUC microphysics with 20km RUC SW-NE vertical cross-section across WA /Olympic Peninsula into BC and Alberta - 12h forecast valid 0300z 5 January km operational RUC at NCEP 20km test RUC w/ microphysics fixes Bug fixes Changes for formation of ice and graupel - result – less “ice friendly” Change in time step from 10 min to 2 min Result: Improved precip type More realistic supercooled liquid water

20 RUC 2m temp ( o C) bias verified against METARS ( ) Analysis3h fcsts 6h fcsts 12 fcsts Much reduced diurnal sfc temp bias with RUC20

21 RUC surface wind forecast verification vs. METARs RUC20/40 west of 105ºWeast of 105ºW

22 METARs – 22z 7 Dec 01 RUC20 sfc wind – 2h fcst – valid 22z LAX

23 RUC20 sfc wind – 12h fcst – valid 06z 8 Dec 01 Divergence - image Conv Div

24 RUC20 divergence – image RUC20 sfc wind – 12h fcst – valid 06z 8 Dec 01 RUC20 model terrain SFO MRY

25 RUC20 divergence – image RUC40 divergence – isopleths (40km data) DEN LBF

26 Precipitation verification RUC40 vs. RUC March – 15 April 2001 Clear superiority of 20km RUC, especially for heavier precipitation events

27 Precipitation verification RUC40 vs. RUC Nov – 3 December 2001 Eq. Threat score Bias

28 12h fcst – init 09z 8 Dec 01 Precip for 3h period – 18-21z RUC40 vs. RUC20 precipitation RUC20 RUC z METARs WSI radar – 2015z

29 24h precipitation 40km RUC vs. 20km RUC 24h period ending 12z 25 Sept 2001 (Two 12h fcsts summed) NCEP/CPC 24h precip analysis 20km RUC 40km RUC

30 Visibility diagnosis 40km RUC vs. 20km RUC 12z 30 January km RUC 40km RUC Observed visibility analysis

31 20km vs. 40km RUC wind forecasts- verification against raobs 3h, 12h forecasts – 25 Nov – 6 Dec 2001 RMS differences 20km 40km RUC20 – Slightly better or equal 3h wind forecasts Consistently improved 12h wind forecasts

32 20km vs. 40km RUC temp / RH forecasts- verification against raobs 12h forecasts – 25 Nov – 6 Dec km 40km RUC20 – Slightly better or equal 3h forecasts Consistently improved 12h forecasts

33 More on RUC20 Same products/fields as for RUC40 (RUC2) 40km look-alike grids –Native (bgrb) –25-mb isobaric and 86 2-d grids (pgrb) –25 2-d variables (sgrb) BUFR sounding output identical to Eta –Current – separate monolithic files for each output time only –New – station files with all output times - ‘monolithic’ file w/ all stations, output times RUC20 forum for questions (under RUC web site) Backup for RUC20 at FSL (similar to current RUC40) RUC web site km test RUC products

34 Summary - the 20km RUC Schedule for implementation –Current – real-time, retro testing at NCEP and FSL –Mar 2002 – field test for RUC users –Implementation – 9 April 2002, 3dVAR follows by ~ 3 months 20 km/50 level 1 hr version –with model improvements including cloud microphysics, convection, land-surface –Improved optimal interpolation analysis, cloud/hydrometeor analysis using satellite combined with explicit cloud fcsts in RUC –Improvements in warm- and cold-season precipitation and cloud/icing forecasts, surface forecasts, wind/RH/temp aloft 10 km RUC – testing at FSL in 2002 w/ current RUC and WRF (NCAR-mass coordinate) models RUC web site km test RUC products