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Operational Use of the Rapid Update Cycle. Stan Benjamin - NOAA/FSL benjamin@fsl.noaa.gov http://maps.fsl.noaa.gov - RUC web page. COMAP Symposium 99-1 20 May 1999. What Runs Where. Rapid Update Cycle (RUC) Operational Version at NCEP Mesoscale Analysis and Prediction System (MAPS)

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Operational use of the rapid update cycle

Operational Use of the Rapid Update Cycle

Stan Benjamin - NOAA/FSL


http://maps.fsl.noaa.gov - RUC web page

COMAP Symposium 99-1

20 May 1999

What runs where
What Runs Where

  • Rapid Update Cycle (RUC)

    • Operational Version at NCEP

  • Mesoscale Analysis and Prediction System (MAPS)

    • Experimental Version at NOAA/ERL/FSL

      (Essentially the same software.

      New capabilities tested first in MAPS at FSL)

Ruc maps purpose
RUC/MAPS Purpose

  • Provide high-frequency mesoscale analyses and short-range forecasts for:

    • aviation

    • severe weather forecasting

    • forecasts for public

    • other transportation

    • agriculture

Operational use of the rapid update cycle

The 1-h Version of the RUC

Data cutoff - +20 min, 2nd run at +55 min at 0000, 1200 UTC

Key personnel ruc 2 development implementation
Key Personnel -- RUC-2 Development/Implementation

Stan Benjamin Analysis/model dev, mgmt

John Brown Model dev, parameterizations

Kevin Brundage NCEP impl., WWW, graphics

Dezso Devenyi 3-d VAR development

Georg Grell Model dev., parameterizations

Barry Schwartz Obs ingest, obs sensitivity studies

Tanya Smirnova Land-sfc processes

Tracy Lorraine Smith Obs ingest, obs sensitivity studies

Tom Schlatter Interaction w/ NCEP

Geoff Manikin NCEP liaison for RUC, impl.

Geoff DiMego Interaction w/ NCEP/NCO, NWS

Uses of the ruc
Uses of the RUC

  • Explicit Use of Short-Range Forecasts

    • Aviation Weather Center - airmets, sigmets

    • Storm Prediction Center - severe weather watches

    • FAA

    • Dept. of Transportation - air traffic management

    • National Weather Service Forecast Offices

    • Airline Forecasting Offices

    • NASA Space Flight Centers

  • Monitoring Current Conditions with Hourly Analyses

  • Evaluating Trends of Longer-Range Models

Hourly data for 40 km maps ruc 2
Hourly Data for 40 km MAPS/RUC-2


**not used since 1/99

pending QC issues

Yellow items new for RUC-2

Hourly data for 40 km maps ruc 2 cont
Hourly Data for 40 km MAPS/RUC-2, cont.

Yellow items new for RUC-2

Real-time observation counts at http://maps.fsl.noaa.gov for RUC-2

and 40-km MAPS

Operational use of the rapid update cycle

Advantages of q Coords for

Data Assimilation


- adaptive 3-d correlation structures and

analysis increments, esp. nearbaroclinic zones

- improved coherence of obs near fronts for QC

Forecast Model

- reduced vertical flux thru coordinate surfaces, leading to reduced vertical dispersion -- much of vertical motion implicit in 2-d horiz. Advection

- conservation of potential vorticity

- reduced spin-up problems (Johnson et al. 93 MWR)

Operational use of the rapid update cycle

RUC-2 Time Availability vs. RUC-1

Improvements due to the 1-hr cycle and earlier data cut-off time

Ruc 2 analysis
RUC-2 Analysis

  • QC - buddy check, removal of VADs w/ possible bird contamination problems

  • 3-part analysis (all using optimal interpolation)

    1) univariate precipitable water (PW) analysis - using satellite PW obs - update mixing ratio field

    2) z/u/v 3-d multivariate analysis - update v based on height/thickness analysis increment, update psfc from height increment at sfc, update u/v at all levels

Ruc 2 analysis cont
RUC-2 Analysis, cont.

3) univariate analysis of condensation pressure at all levels, v at all levels. Also update u/v near sfc and psfc with univariate analysis with smaller correlation lengths

  • Update soil temp at top 2 levels to maintain (Tskin - T1-atmos)

  • Pass through soil moisture, cloud mixing ratios, snow cover/temperature (will alter these fields at future time)

Ruc 2 analysis cont1
RUC-2 Analysis, cont.

  • Vertical spreading (correlation of forecast error) based on potential temperature separation (not pressure separation as w/ other models)

  • Analysis in generalized vertical coordinate (code applicable to pressure, sigma, or eta analysis) except for adjustment at end to reference potential temperatures and new psfc

  • Background is usually previous 1 hr RUC forecast

Operational use of the rapid update cycle

Raob sounding RUC2 sounding

Close fit to observations in RUC2 analysis

Operational use of the rapid update cycle

Raob RUC after fix RUC before fix

7 April 99 significant-level fix in RUC-2

Rucs 60 km hourly surface analyses
RUCS 60 km Hourly Surface Analyses

  • Draws fairly closely to data

  • Persistence background field (1 hr previous analysis

    • some QC problems

    • no consistency with terrain

  • MAPS sea-level pressure, (Benjamin & Miller, 1990 MWR)

  • Blending to data-void region from NGM

Surface analyses forecasts in ruc 2
Surface Analyses/Forecasts in RUC-2

  • integrated with 3-d 40 km 1 hr cycle

  • dynamic consistency with model forecast => accounts for:

    • land/water, mtn circulations, sea/lake breezes, snow cover, vegetation…

  • improved quality control - model forecast background prevents runaway bullseyes

  • forecasts out to 12 hr in addition to hourly analyses

Surface analyses forecasts in ruc 2 cont
Surface Analyses/Forecasts in RUC-2, cont.

  • Same fields as in 60 km RUCS, plus all fields available in 3-d system

    RUC-2 sfc files (GRIB)

    0.3 MB / output time

    all variables from RUCS plus


    precip type

    stability indices

Ruc 2 use of surface data
RUC-2 use of surface data

All winds, sfc pressure obs used

T/Td used if abs (Pstation - Pmodel) < 70 mb

- about 90% west of 105ºW, 99% east of 105ºW

|pmodel - pstn|

** w/I 5 mb of closest fit

Ruc 2 model
RUC-2 Model

  • Prognostic variables

    • Dynamic - (Bleck and Benjamin, 93 MWR)

      • v, p between levels, u, v

    • Moisture - (MM5 cloud microphysics)

      • q v, qc, qr, qi, qs, qg, Ni (no. conc. ice particles)

    • Turbulence - (Burk-Thompson, US Navy, 89 JAS)

    • Soil - temperature, moisture - 6 levels (down to 3 m)

    • Snow - water equivalent depth, temperature

      (soil/snow/veg model - Smirnova et al., 1997 MWR)

Ruc 2 model cont
RUC-2 Model, cont.

  • Numerics

    • Continuity equation

      • flux-corrected transport (positive definite)

    • Advection of v, all q (moisture) variables

      • Smolarkiewicz (1984) positive definite scheme

    • Horizontal grid

      • Arakawa C

    • Vertical grid

      • Non-staggered, generalized vertical coordinate currently set as isentropic-sigma hybrid

Ruc 2 model cont1
RUC-2 Model, cont.

  • Cumulus parameterization

    • Grell (Mon.Wea.Rev., 1993)

    • simplified (1-cloud) Arakawa-Schubert

    • includes effects of downdrafts

  • Digital filter initialization (Lynch and Huang, 93 MWR)

    • +/- 40 min adiabatic run before each forecast

Mm5 level 4 microphysics
MM5 Level 4 Microphysics

  • Predicts mixing ratios of water vapor, cloud water, rain water, cloud ice, snow, graupel and number concentration of cloud ice

  • Ongoing improvements in collaboration with NCAR/RAP

  • Continuous cycling of liquid and solid hydrometeors

  • NCEP C-90 CPU usage (12 hr forecast):

    • 10% microphysics

    • 15% advection of hydrometeors

Operational use of the rapid update cycle

Montreal ice storm - 9h RUC2 forecast valid 2100 9 Jan 98.

N-S cross sections of RUC2 microphysics


Operational use of the rapid update cycle





(Smirnova et al.

1997, MWR)

Ongoing cycle

of soil moisture,

soil temp, snow


Fields from soil snow model
Fields From Soil/Snow Model

  • Soil temperature at 6 levels

  • Soil moisture at 6 levels

  • Surface runoff

  • Sub-surface runoff

  • Direct evaporation from bare soil

  • Evapotranspiration

  • Evaporation of canopy water

  • Condensation of water

  • Canopy water

  • Water dripping from the canopy

Fields from soil snow model cont
Fields From Soil/Snow Model, cont.

  • Snow depth

  • Snow temperature

  • Accumulation of snow

  • Amount of melted snow

  • Flux of snow phase change heat

    • Predicted soil variables cycled since April 1996

    • Predicted snow variables cycled since March 1997

Ruc 2 output files
RUC - 2 Output Files

  • Isobaric main (25 mb, 212 grid)

    • 6 3-d variables (ht, temp, RH, u/v, vv)

    • 80 2-d variables (prec, indices, spec. level, …)

    • ~7 MB / output time

  • Surface fields (212 grid)

    • 25 2-d variables (p, T, TD, u/v, 3-h dp, precip, indices…)

    • ~0.3 MB / output time

Ruc 2 output files cont
RUC - 2 Output Files, cont.

  • 211 isobaric/sfc grids (will add vert. Vel.)

  • BUFR hourly soundings - same format as Eta

    • ~290 stations

    • ~1.5 MB for 12-h fcst, all stations (week of 12/8/97)

  • Native -

    • ~10 MB / output time

Improvements in 40 km ruc 2 over ruc 1
Improvements in 40-km RUC-2over RUC-1

  • Wind analyses/forecasts - improved skill at all times

  • Temperature - improved skill, much reduced bias

  • RH - improved skill, much reduced bias

  • Turbulence -

    • sharp, coherent structures near frontal zones

Improvements in 40 km ruc 2
Improvements in 40-km RUC-2

  • Icing -

    • explicit microphysics with cloud water/rain/snow/ice/graupel

  • Surface forecasts -

    • substantial improvement from addition of surface physics (multi-level soil/vegetation model, snow physics), clouds, improved radiation

  • Precipitation -

    • much better especially in orographic precip and heavy precip events

Directions for future ruc 2 improvements suggested by precipitation verification
Directions for Future RUC-2 Improvements(suggested by precipitation verification)

  • Improve cloud/moisture analysis.

    • Use of advanced microphysics in RUC-2 means that initial cloud errors can lead to underforecasting. Work is underway to add satellite, radar and surface data to forecast cloud fields.

  • Introduce fractional cloudiness into the model

    • Allow supersaturation at <100% RH within 40 km grid boxes

  • Convective parameterization (Grell, includes effect of downdrafts)

    • Gives reasonable performance but still needs tuning/improvement

Dec 98 change bundle for ruc 2
Dec 98 change bundle for RUC-2

  • Y2K fixes

  • Analysis changes

    • smaller horiz. error correlation near sfc for T/Td, slightly less dependence on stability => improved sfc T/Td fit in mtns

    • fix to use of cloud drift winds => will have much more effect (over water only)

    • better fit to sfc obs

  • Model changes

    • fixes to sfc physics - reduction of cool bias in daytime

    • fixes to radiation - more cooling at night, slightly more heating in daytime

    • less convective precip over warm water

Dec 98 change bundle for ruc 2 cont
Dec 98 change bundle for RUC-2, cont.

  • Diagnostic fixes

    • CAPE/CIN - mix lowest 30-40 mb - less jumpiness from analysis to 1h fcst

    • tropopause level fix

  • GRIB table fixes

    • Allow soil cycling with adequate precision

  • Boundary condition fix to account for Eta change in RH as of 11/3/98

Apr 99 emergency change for ruc2
Apr 99 emergency change for RUC2

  • Correctly uses raob sig-level temp/dewpoint data now.

  • Previously, missed sig-level T/Td data (TTBB) and forced in linearly interpolated structures between mandatory levels.

  • Significant improvement in RUC grid sounding structures and in overall RUC performance

May 99 post proc fixes for ruc2
May 99 post-proc fixes for RUC2

  • Bug/consistency fixes for diagnosis of sfc T/Td in RUC2. (fix to lapse rate range)

    • Biases in west US for T/Td reduced, 2 °C  0

    • s.d. temps over US from 2.0  1.4 °C

    • (verification against METAR obs)

  • CAPE- searches lowest 300 mb, not 180 mb

  • More smoothing of isobaric winds in lower troposphere, near tropopause

  • Use of NESDIS ice field

  • Much faster running of RUC - 10 procs for all runs

Ruc 2 weaknesses
RUC-2 Weaknesses

  • Still some precip spin-up problem, despite cycling of cloud/precip variables, esp. for light precip/overrunning (1-3 hr late)

    • Fix: Add cloud analysis - 1999 - 1st version, allow for cloud at RH < 100%

  • Too much precip over warm oceans, too little near SE coast in cold season

    • Dec 98 fix package helped some - work underway on fixing tendencies input to Grell convective parameterization

  • Daytime convective precip in summer too widespread

    • Upcoming fix on tendencies input to Grell scheme

  • Ruc 2 weaknesses cont
    RUC-2 Weaknesses, cont.

    • Convective precip forecasts miss many small areas, underforecast peak amounts.

      • Lower equitable threat score than Eta

      • more detailed than Eta

    • Too much graupel near 0ºC

      • Fix: with 20-km RUC, collaboration with FSL and NCAR on microphysics fixes

  • Diurnal cycle of surface temperature a little too weak

    • a little too warm at night

      • Dec 98 fix package - sfc flux change, radiation fix, GRIB precision to allow proper soil moisture cycling

      • May 99 fix - improve diagnosis of sfc temp/Td diagnosis -- significant reduction in bias

  • Ruc 2 weaknesses cont1
    RUC-2 Weaknesses, cont.

    • Detailed (noisy?) output compared to other models, especially vertical velocity

      • Detail is probably realistic over terrain

    • Analysis near coastlines

      • does not account for land/sea contrast

      • analysis increments over coast extrapolated over sea

        Fix: Account for lower horizontal correlation in analysis when crossing coastline

    Fixed ruc 2 weaknesses
    Fixed RUC-2 Weaknesses

    • Analysis sounding structure

      • irregular near ground if only sfc data assimilated

        Fix: analysis tuning (Dec 98)

        Fix: sig-level bug fix (Apr 99) *****************

    • CAPE/CIN

      • analysis values previously too high in high CAPE areas

      • jump between analysis and 1-h forecasts

        Fix: CAPE software (Dec 98)

        (May 99 - parcel search now in lowest 300 mb, not 180 mb layer)

    Ruc 2 strengths
    RUC-2 Strengths

    • Surface fields, esp. surface winds

      • sfc files

        • analysis and forecast

        • small

        • standard sfc fields plus precip, stability, precip type

    • Topographically induced circulations

      • sea/lake breezes (scale too large but they’re there)

      • mtn/valley circulations

      • differential friction effects

    Ruc 2 strengths cont
    RUC-2 Strengths, cont.

    • Precipitation fields

      • more detailed than Eta (lower FAR but lower POD)

    • Snow accumulation

      • explicit, not diagnosed (from MM5 microphysics)

    • Precip. type

      • uses explicit hydrometeor mixing ratios/fall rates

    • Upper-level features

      • hybrid / coordinate

      • winds, PV, temps, fronts, more coherent vorticity structures on isobaric surfaces

    Ruc 2 strengths cont1
    RUC-2 Strengths, cont.

    • Lower tropospheric temp/RH

      • good fcst sounding structure (esp. after 4/99 fix)

      • hybrid coordinate

    • Soil/hydro fields

      • soil moisture - cycled in 6-level soil model

      • surface runoff, canopy water, dew formation, etc.

    • Vertical velocity

      • available in RUC-2

      • good mtn wave depiction, frontal features

    • Hourly analyses

      • available much sooner than RUC-1 grids

      • (4/99 speed-up in RUC processing at NCEP, 12h fcsts available 30 min sooner, analyses available 8-10 min sooner)

    Ruc maps web resources
    RUC/MAPS Web Resources

    • Main RUC/MAPS home page

      • http://maps.fsl.noaa.gov

    • RUC2 discussion forum

      • maps.fsl.noaa.gov/forum/eval

    • RUC2 real-time data inventory

      • maps.fsl.noaa.gov/final.ruc_data.html

    • RUC2 Tech. Proc. Bulletin

      • maps.fsl.noaa.gov/ruc2.tpb.html

    Ruc maps web resources cont
    RUC/MAPS Web Resources, cont.

    • RUC-2 diagnosed variables - explanation of each

      • maps.fsl.noaa.gov/vartxt.cgi

    • RUC-2 evaluation from Nov 97 - Jan 98 field test

      • maps.fsl.noaa.gov/ruc2.evalsum.html

    • Experimental 36h fcsts run at FSL

    • Parallel cycle w/ latest experiments (e.g., cloud analysis)

    • AFDs/SFDs using RUC (http://maps.fsl.noaa.gov/sfd)

      • used to monitor NWS use of RUC

    The future of the ruc
    The Future of the RUC

    • Transfer of current 40km RUC2 to IBM SP-2 - July 1999

      • faster, distributed post-processing

    • 20 km 1 hr version on IBM SP-2

      • Probably in early 2000

      • 3-d variational analysis

      • Cloud/hydrometeor analysis using satellite, radar, surface, aircraft combined with explicit cloud fcsts in RUC-2

    • Later, assimilation of new data sets: sat. cloudy/clear radiances (GOES/POES), hourly precipitation analyses, WSR-88D radial winds, lightning, GPS precipitable water, sat water vapor winds

    The future of the ruc cont
    The Future of the RUC, cont.

    • Improved physical parameterizations, including cloud microphysics (freezing drizzle), surface physics (frozen soil, high-resolution soil and surface data sets), and turbulence physics

  • Higher resolution versions

    • 15-20 km/60 level - expanded domain - early 2001

    • trade-off between resolution and domain?

  • Operational use of the rapid update cycle

    20km RUC


    - early 2000

    The future of the ruc cont1
    The Future of the RUC, cont.

    • Non-hydrostatic -z model under development

      • Generalized vertical coordinate

      • Nudging of coordinate surfaces toward “grid generator”

        • can be set as smoothed quasi-isentropic hybrid coordinate

          • treats sub~20km variations (convective clouds, breaking mountain waves) w/ quasi-horizontal coordinates

          • treats >20km variations w/ -z coordinates

      • Collaboration between University of Miami (Rainer Bleck, Zuwen He), FSL (John Brown, Stan Benjamin), and NCAR (Bill Skamarock)

      • Part of WRF model (Weather Research and Forecast - NCAR/FSL/NCEP/CAPS) effort - a generalized vertical coordinate option.

      • WRF-based RUC probably by 2005-6 at 5-10km scale

      • 30-min cycle or finer?


    • Send feedback/questions on RUC performance to the RUC discussion forum.

    • Invite us to workshops.

    • http://maps.fsl.noaa.gov/forum/eval