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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) *****************

    • 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]