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Operational Use of the Rapid Update Cycle. Stan Benjamin - NOAA/FSL [email protected] 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

[email protected]

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

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

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)

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

Raob sounding RUC2 sounding

Close fit to observations in RUC2 analysis

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

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

N-S cross sections of RUC2 microphysics






(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?

  • 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


      [email protected]