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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. Stan Benjamin NOAA / FSL [email protected] 303-497-6387 http://ruc.fsl.noaa.gov.

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testing and upcoming implementation of the 20km ruc
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

Stan Benjamin


[email protected]



Testing and Upcoming Implementation of the 20km RUC

NCEP Production Suite Review

11 December 01 – updated 15 Feb 02

key goals for 20km ruc
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 q/s coordinate,
  • cloud analysis
ruc20 testing since may 2001
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
ruc20 implementation schedule
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
Subset of full domain

Model terrain elevation

40km RUC

20km RUC

Subset of full domain

Model terrain elevation

40km RUC

20km RUC

20km RUC

50 levels

40km RUC

40 levels

800 1600 2400 3200

RUC native coordinate levels

10 new levels

7 – upper levels – 330 – 500 K

3 – lower levels – 270 – 290 K

W-E vertical cross-section

- Pacific – w. coast

6h fcsts valid 0000 UTC 24 Feb 2001

rapid update cycle present and next version
Rapid Update Cycle – Present and Next Version

Current Operations – RUC40 RUC20

Resolution 40 km, 40 q/s levels 20 km, 50q/s levels

Analysis Optimal interpolation on Modified OI technique on generalized

on generalized q/s surfaces q/s surfaces, hydrometeor analysis w/

GOES…, use raw instead of interp. obs

Assimilation Intermittent 1-h cycle Intermittent 1-h cycle

Stable clouds Mixed-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-scale Grell (1993) New Grell scheme w/ ensemble cloud,

precipitationshallow convection, detrainment of

cloud water to microphysics

Turbulence Burk-Thompson explicit TKE scheme Modified Burk-Thompson

Radiation MM5 LW/SW scheme, f(hydrometeors) MM5 scheme with fix to SW lag error

Land-sfc processes 6-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 conditions Daily 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 12h Eta model initialized every 6h

key ruc20 modifications since may 2001
Key RUC20 Modifications Since May 2001
  • 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 for 20 km ruc at ncep
Data for 20-km RUC at NCEP

New for 20km RUC at NCEP

Data Type ~Number Freq.

Rawinsonde (inc. special obs) 80 /12h

NOAA 405 MHz profilers 31 / 1h

Boundary-layer (915 MHz) profilers ~24 / 1h *

VAD winds (WSR-88D radars) 110-130 / 1h

Aircraft (ACARS) (V,temp) 1400-4500 / 1h

Surface/METAR - land (V,psfc,T,Td) 1500-1700 / 1h

Buoy 100-150 / 1h

GOES precipitable water 1500-3000 / 1h

GOES cloud drift winds 1000-2500 / 1h

GOES cloud-top pressure ~40km res / 1h

SSM/I precipitable water 1000-4000 / 6h

GPS precipitable water ~80 / 1h *

Ship reports 10s / 3h

Reconnaissance dropwinsonde a few / variable



improved use of obs in ruc20 analysis
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
Comparison of

obs sounding vs.

grid point soundings

for RUC40 vs. RUC20

1200 UTC

9 Dec 2001

Grand Junction, CO



Better near-surface fit to obs

with RUC20

20km – mod OI

40km - OI

initial ruc cloud analysis technique
Initial RUC cloud analysis technique

Goal – Improve RUC precipitation, cloud, icing forecasts

  • 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
Processes in RUC/MM5 microphysics

(Reisner, Rasmusssen, Bruintjes, 1998, QJRMS)

3h 20km RUC cloud-top fcst

w/ GOES cloud assimilation


Cloud-top pressure

based on NESDIS product

Effect of GOES data on

3-h RUC cloud-top fcsts

Valid 1200 UTC

9 Dec 2001

3h 40km RUC cloud-top fcst

No GOES cloud assimilation

40km RUC

20km RUC w/ cloud analysis

3h 20km RUC cloud-top fcst

w/ GOES cloud assimilation


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 2001

key changes in 20km ruc forecast model for qpf
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
  • -- 10  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
ruc land surface process parameterization
RUC Land-surfaceProcess Parameterization

Purpose – Improve near-surface,

precipitation, cloud forecasts

Ongoing cycle of soil moisture,

soil temp, snow cover/depth/temp)


  • New in 20km
  • change in thermal conductivity – better diurnal cycle
  • frozen soil physics, 2-layer snow model, high resolution land-use, soil type data


changes to mm5 ruc microphysics with 20km ruc
Changes to MM5/RUC microphysics with 20km RUC
  • Result:
  • Improved precip type
  • More realistic supercooled liquid water

Bug fixes

Changes for formation of ice and graupel

- result – less “ice friendly”

Change in time step from 10 min to 2 min

40km operational RUC at NCEP

20km test RUC w/ microphysics fixes

SW-NE vertical cross-section across WA /Olympic Peninsula into BC and Alberta - 12h forecast valid 0300z 5 January 2001

RUC 2m temp (oC) bias verified

against METARS ( 01152-01205 )

Much reduced

diurnal sfc temp bias with RUC20


3h fcsts

6h fcsts

12 fcsts

RUC surface wind forecast


vs. METARs


west of 105ºW

east of 105ºW

METARs – 22z 7 Dec 01

RUC20 sfc wind – 2h fcst – valid 22z






RUC20 sfc wind – 12h fcst – valid 06z 8 Dec 01

Divergence - image



RUC20 divergence – image

RUC20 sfc wind – 12h fcst – valid 06z 8 Dec 01

RUC20 model terrain


RUC20 divergence – image

RUC40 divergence – isopleths

(40km data)


Precipitation verification

RUC40 vs. RUC 20

20 March – 15 April 2001

Clear superiority of 20km RUC,

especially for heavier precipitation


Precipitation verification

RUC40 vs. RUC 20

12 Nov – 3 December 2001

Eq. Threat score


ruc40 vs ruc20 precipitation
2000z METARsRUC40 vs. RUC20 precipitation



12h fcst – init 09z 8 Dec 01

Precip for 3h period – 18-21z

WSI radar – 2015z


24h precip


40km RUC


24h precipitation

40km RUC vs. 20km RUC

24h period ending 12z 25 Sept 2001

(Two 12h fcsts summed)




40km RUC

Visibility diagnosis

40km RUC vs. 20km RUC

12z 30 January 2002


20km vs 40km ruc wind forecasts verification against raobs
20km vs. 40km RUC wind forecasts- verification against raobs

3h, 12h forecasts – 25 Nov – 6 Dec 2001

RMS differences


RUC20 –

Slightly better or equal 3h wind forecasts

Consistently improved 12h wind forecasts

20km vs 40km ruc temp rh forecasts verification against raobs
20km vs. 40km RUC temp / RH forecasts- verification against raobs

12h forecasts – 25 Nov – 6 Dec 2001


RUC20 – Slightly better or equal 3h forecasts

Consistently improved 12h forecasts

more on ruc20
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- http://ruc.fsl.noaa.gov - 20km test RUC products

summary the 20km ruc
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- http://ruc.fsl.noaa.gov - 20km test RUC products