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Operational Use of the Rapid Update Cycle
COMAP Symposium
16 December 1999
Stan Benjamin - NOAA/[email protected]://maps.fsl.noaa.gov
- RUC/MAPS web page
The 1-h Version of the RUC
Data cutoff - +20 min, 2nd run at +55 min at 0000, 1200 UTC
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RUC/MAPS Purpose
• Provide high-frequency mesoscale analyses and short-range numerical forecasts for users including:– aviation– severe weather forecasting– general public forecasting– other transportation– agriculture
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)
Uses of the RUC• Explicit Use of Short-Range Forecasts• Monitoring Current Conditions with Hourly Analyses• Evaluating Trends of Longer-Range Models
Some places where the RUC is used– Aviation Weather Center - airmets, sigmets– Storm Prediction Center - severe weather watches– FAA – CWSUs, WARP, air traffic management (CTAS), ITWS..– National Weather Service Forecast Offices– Airline Forecasting Offices– NASA Space Flight Centers– Private vendors
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NWS Forecast Discussion Use of RUC - Feb-Nov 1999
100-400
40-99
20-39
10-19
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http://maps.fsl.noaa.gov
Hourly Data for 40 km MAPS/RUC-2
Yellow items new for RUC-2**not used since 1/99 in RUCor EDAS pending QC issues
Data Type ~Number Freq. Use
Rawinsonde (inc. special obs) 80 /12h NCEP and FSLWPDN/NPN profilers 31 / 1h NCEP and FSL
- 405 MHzBoundary layer profilers 15 / 1h FSL onlyRASS (WPDN and PBL) 15 / 1h FSL onlyVAD winds (WSR-88D) 110-130 / 1h **NCEP & FSLAircraft (ACARS)(V,temp) 700-3000 / 1h NCEP and FSLSurface - land (V,psfc,T,Td) 1500-1700 / 1h NCEP and FSLBuoy 100-200 / 1h NCEP and FSL
Hourly Data for 40 km MAPS/RUC-2 (cont).
Yellow items new for RUC-2
Data Type ~Number Freq. Use
GOES precipitable water 1000-2500 / 1h NCEP and FSLGOES high-density cloud drift winds (IR, VIS, WV cloud top) 1000-2500 / 3h NCEP and FSLSSM/I precipitable water 1000-4000 /2-6h NCEP onlyShip reports 10s / 3h NCEP onlyReconnaissance
dropwinsonde a few / variable NCEP only
Real-time observation counts at http://maps.fsl.noaa.gov for RUC-2 and 40-km MAPS
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Advantages of Coords for Data Assimilation
Analysis
- adaptive 3-d correlation structures and analysis increments, esp. nearbaroclinic zones- improved coherence of observations near fronts for QC
Forecast Model
- reduced vertical flux through 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 hybrid-b levels - cross-section
Hybrid-b levels- solid
levels (every 6 K)- dashed
No discontinuitiesat transitions
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Effect of vertical coordinateon frontal features
Turbulence diagnosticat FL200 (20,000 ft)
- calculated from native grid from both MesoEta and RUC (matched forecast times)
Sharper frontal resolution with RUC despite coarser horizontal resolution and fewer vertical levels
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Rapid Update Cycle – Present and Next Version1999 Operations 2000-01 Operations
Resolution 40 km, 40levels 2015 km, 40 50-60 levels
Analysis Optimal interpolation on 3-d variational technique on generalized on generalized surfaces surfaces, hydrometeor analysis w/
GOES…, use raw instead of interp. obsAssimilation Intermittent 1-h cycle Intermittent 1-h cycle
Stable clouds Mixed-phase cloud microphysics MM5), Improved microphysics, / precipitation explicit fcst of cloud water, rain water, addition of drizzle
snow, ice, graupel, no. concentration of ice particles
Sub-grid-scale Grell (1993) Modified Grell, scale dependence, precipitation shallow convection, interaction w/
cloud microphysics Turbulence Burk-Thompson explicit TKE scheme Refined Burk-Thompson or e-
Radiation MM5 LW/SW scheme, f(hydrometeors) Refined MM5 scheme
Land-sfc processes 6-level soil/veg model (Smirnova, Add vertical soil type variability, 1997, 1999) w/ frozen soil, 2-layer snow improved cold season processes
Sfc conditions Daily 50km SST/14 km LST, Combine sat Tskin, use 3-d soil type 0.14 monthly NDVI veg frac, cycled soil moisture/temp, snow depth/temp
RUC-2 Analysis
• Background (1-h fcst usually) subtracted from all obs– Analysis is of forecast error
• 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 analysis increment at sfc• update u/v at all levels• Partial geostrophic balance – vertically dependent, weakest at surface
RUC-2 Analysis, cont.
- 3) univariate analyses • condensation pressure at all levelsv at all levels
• update u/v near sfc and psfc (univariate analysis) with smaller correlation lengths
• Pass through soil moisture, cloud mixing ratios, snow cover/temperature (will alter these fields in future, cloud analysis parallel cycle now running)
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
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Raob sounding RUC2 grid sounding
Close fit to observations in RUC2 analysis
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Raob RUC after fix RUC before fix
7 April 99 significant-level fix in RUC-2
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Use of ‘minimum topography’for 2m T/Td fields from RUC2
RUC2 2m T/Td fields are not valid at model terrain surface
Instead, they are derived from model surface fields and lapse rates in lowest 25 mb to estimate new values using a different topography field that more closely matches actual METAR elevations
“Minimum topography” – minimum 10km value inside each 40km grid box, then updated with high-resolution analysis using actual METAR elevations.
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Minimum topo for 2m T/Td
Model topo
RUC2 topography fields
RUCS 60 km Hourly Surface Analyses (same as AWIPS MSAS)
• Draws fairly closely to data• Persistence background field (1 hr previous
analysis– QC vulnerable to consistent data problems– no consistency with terrain effects except as reflected
in observations
• MAPS sea-level pressure, (Benjamin & Miller, 1990 MWR)
• Blending to data-void region from NGM
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
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RUC2 Surface Analysis Topographical features more evident with model background
RUCS 60km surface analysis Little consistency with nighttime drainage
Divergence - 0900 UTC 20 Jan 98(blue - conv, green/yellow - div)
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Divergence - RUC2 Surface Analysis - 0600Z 19 April 96
Consistency with topographical features in model(land/water roughness length variations in this case)
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
precip type
stability indices
RUC-2 use of surface dataAll winds, sfc pressure obs usedT/Td used if abs (Pstation - Pmodel) < 70 mb
- about 90% west of 105ºW, 99% east of 105ºW
Eta48 Eta29 RUC40FGZ 0 18 10TUS 60 13 44SLC 59 68 59MFR 109 48 67OAK 18 15 25SAN 12 5 23DRA 42 29 34GJT 98 105 65RIW 104 27 16GEG 4 11 1GTF 26 4 14UIL 14 9 11SLE 50 15 22BOI 55 21 24GGW 29 13 5VBG 5 32 3
** within 5 mb of closest fit
|pmodel - pstn|
RUC surface temperature forecasts- verification against all METARs in RUC domain
RMS error Bias (obs - forecast)
persistence
Validation time Validation time
Excellent analysis fit to surface obs (also wind, Td)3-h forecast better than 3-h persistence
1
1.5
2
2.5
3
00z 03z 06z 09z 12z 15z 18z 21z
national surface temperature verification99160-99182
3-hpers
anx
3-h
RM
S t
emp
era
ture
err
or
(0C
)
cycle
-4
-3
-2
-1
0
1
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00z 03z 06z 09z 12z 15z 18z 21z
national surface temperature bias verification99160-99182
3-hpers
anx
3-h
tem
pe
ratu
re b
ias
(0C
)
cycle
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Effect of 6 May 1999 Fix to surface temperature diagnosis in RUC2
Improved lapse rates inextrapolation from RUC2model terrain to differentterrain file (“minimum topography”) used forsfc T/Td diagnosis.
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-3 -2 -1 0 1 2 3 4 5 g/kg
Analysis increment fields (1h forecast error correction)RUC analysis2200 UTC 29 Oct 1999
Sfc virtual pot temp Sfc water vapor mix ratio
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Windanalysis increment fields (forecast error correction)-RUC analysis2200 UTC 29 Oct 1999
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Vertical cross-section – 2200 UTC 29 Oct 99RUC 3-d analysis
Need for 3-d consistency to initialize model,other diagnostics
SLC CYS
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.
• 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, cont.
• Cumulus parameterization– Grell (Mon.Wea.Rev., 1993)– simplified (1-cloud) version of Arakawa-
Schubert– includes effects of downdrafts
• Digital filter initialization (Lynch and Huang, 93 MWR)– +/- 40 min adiabatic run before each forecast
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RUCDigital FilterInitialization
40 t forward40 t backward- digital filter avgof model values
Produces muchsmoother 1-h fcst
Mean absolute sfc pres tendency each t in successive RUC runs
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Processes in RUC2/MM5 microphysics (Reisner, Rasmusssen, Bruintjes, 1998, QJRMS)
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RUC2 case study - Quebec/New England ice storm - 9 Jan 1998500 mb height/vorticity - 9h RUC2 fcst valid 2100 UTC
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RUC2 9h fcst - Surface temp (image), MSLP (beige isobars)
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YUL
N-S cross-section - temperature (isopleths, int = 2 deg C, solid for > 0)RH (image), 9h RUC2 forecast
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Montreal ice storm - 9h RUC2 forecast valid 2100 9 Jan 98.N-S cross sections of RUC2 microphysics
| YUL/Montreal| YUL/Montreal
Water vapor mixing ratio / Cloud water mixing ratio
Graupel mixing ratioRain water mixing ratio
40 km RUC versus 32 km Eta
June-July1999
40 km RUC versus 32 km Eta
June-July1999
RUC vs. Eta 12-h fcsts250mb RMS vector error
From 80km grids for both modelsRUC uses 24h Eta for lateral boundary conditions
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6
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-4
-2
0
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98 105 112 119 126 133 140 147 154 161 168 175 182
250 mb wind vector verification
RU
C m
inus
Eta
vec
tor
diff
eren
ce
(ms
-1)
julian day (1999)
Eta better
RUC better
Comparable skill, potential for ensembles
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RUC 1, 3, 6, 12h forecasts valid at same time
Better wind and temperature forecasts with use ofmore recent asynoptic data
(against 0000 and 1200 UTC rawinsonde data)
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RUC/MAPSLand-surfaceProcessParameterization
(Smirnova et al.1997, MWR;1999, JGR)
Ongoing cycleof soil moisture,soil temp, snowcover/depth/temp)
2-layer snow model
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Addition of high-resolution EOS vegetation-type data to current 40km MAPS
- September 1999
Previous MAPS vegetation New vegetation – BATS classes
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RUC/MAPS cycling of soil/snow fields- soil temperature, soil moisture- snow water equivalent, snow temperature
MAPS snow water equivalent depth (mm) 5 Jan 1999 1800 UTC
NESDIS snow cover field5 Jan 1999 2200 UTC
1” 2” 3” 4” 5”
RUC2 Output Files, cont.• Significant changes to RUC AWIPS output
Already started after NCEP fire
– AWIPS files produced as each part of RUC is complete (analysis, 3h, 6h, 9h, 12h) rather than all produced after end of RUC forecast run
– Hourly output of analysis and 3h fcst– New variables added - vertical velocity (3-d), lots of 2-d grids– New 2-d variables - cloud top/base, visibility, gust speed, PBL height,
conv cloud top, eq level, pres(max e)
Likely to start within next few months
– 212 grids (236 subset of 212 - 151x113 RUC domain) will be available (not certain of comms yet)
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Examples of new diagnostic fields from RUC
Visibility Sfc wind gust speed
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RUC visibility and ceilingvs.
METAR IFR/MVFR1700 UTC 4 Dec 1999
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Maintenance of operational RUC Operational production at FSL of backup RUC products in real time from 1 Oct thru 15 Nov 1999
Software and scripts developed and implemented on separate SGI Origin for backup. Monitoring, verification, new web sites, web forum Daily coordination with NCEP and NWS/OSO
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1-h fcst w/o GOES cloud assim
1-h fcst w/ hourly GOES cloud assim NESDIS cloud-top (verification)
RUC/MAPS 1-h cloud-top fcsts with and without GOES cloud-top assimilation (clearing and building) (1200 UTC 14 May 1999)
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1-h MAPS cloud-top fcst with previous GOES assimilation -- valid 18z 28 Oct 99
Visible satellite image at 1745z 28 Oct 99
Correspondence between MAPS cloud fcsts and sat images- improved with GOES cloud-top assimilation
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Control - no cloud analysis Parallel - with cloud analysis
September 1999 - fall
Significant improvement in RUC cloud-top forecasts withcloud analysis, esp. for 1-h forecasts, but smaller but consistent improvement even in 12-h forecasts
0.7
0.5
0.3
Cloud-top verification with and without initial cloud analysis - correlation coefficient between RUC forecasts and NESDIS cloud-top pressures
Julian date
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Verification of MAPS cloud-top fcsts against NESDIS product
Frequency scatter plot for each MAPS grid point
Cloud tops validSunday 21 Nov 991800 UTC
pres
9-h fcsts
1-h fcstsParallel runw/ GOES
Control runno GOES
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Impact of GOES cloud-top assimilation in MAPS parallel cycle test- July-August 1999
Improved 3h RH forecasts with GOES cloud assimilation,especially at 300-500 hPa. Less impact at 850-700 hPa.
w/ GOES No GOES
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Visible satellite image at 1745z 28 Oct 99
NESDISCloud-top product(sounder-based) 1800z 28 Oct 99
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Addition of national radar data to RUC cloud analysis
Access software for national radar (both 4km NEXRAD and 2km NOWRAD) data developed
Initial comparisons between GOES cloud-top pressures andnational radar data – both mapped to RUC 40km grid
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
• 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
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June 99 fix to veg fraction bug
Vegetation fraction in RUC was erroneously set to zero due to integer/real problem (only a problem w/ NCEP RUC, not in FSL MAPS/RUC)
Responsible for warm bias from 2100-0900 UTC increasing during May. Also resulted in dry bias and too little precip
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July/Sept/Nov/Dec 1999 fixes
26 July - fix to moisture in RUC boundary conditionsfrom Eta- Eliminate erroneous precip near RUC boundariesespecially over warm oceans
28 Sept – start IBM version of RUC – faster post-processing21 Nov – fix canopy water cycling problem that had caused
too moist soil for about 1 weekDec ? – 8 new variables in post-processing – visibility, cloud base/top, sfc wind gust, PBL height, conv. Cld top, equilibrium level, pres of max theta-e
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
• Fix now running in backup RUC – look at web page prods• Daytime convective precip in summer too widespread
• Upcoming fix on tendencies input to Grell scheme• Fix now running in backup RUC
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 (perhaps sooner), 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• Upcoming fix to SW radiation 0-60 min phase delay
• Detailed (noisy?) output compared to other models, especially vertical velocity– Detail is probably realistic over terrain
Fixed RUC-2 Weaknesses• Analysis sounding structure
– irregular near ground if only sfc data assimilatedFix: 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 forecastsFix: CAPE software (Dec 98)(May 99 - parcel search now in lowest 300 mb, not 180 mb
layer)
RUC-2 Strengths• Surface fields, especially 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
• e.g. – Catalina eddy
RUC-2 Strengths, cont.• Precipitation fields
– more detailed than Eta (lower FAR but lower POD)
• Snow accumulation– explicit, not diagnosed (from MM5 microphysics)
• Precipitation 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, 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
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Mtn wave comparison - MesoEta vs. RUC2
RUCMesoEta
Theta
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MesoEta RUC
U - component
Mtn wave comparison - MesoEta vs. RUC
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W - vertical velocity
Mtn wave comparison - MesoEta vs. RUC
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20km RUC/MAPS topography - 2000
Will use • 20km versions of
• EOS veg data • 3-d STATSGO soil data
• improved data assimilation (sat cloud products, 3dVAR, later - radar, sfc cloud data, lightning, GPS IPW)
Subset of full domain
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13km RUC - 12h forecast - start 0000 UTC 27 October 1997
PrecipitationSurface winds
7913km RUC - 6h forecast valid 06Z 27 Oct 97 6-h precipitation (cm), wind speed (m/s) in cross-section
1020
2025
The Future of the RUC
• Transfer of current 40km RUC2 to IBM SP – completed Sept 1999– faster, distributed post-processing
• 20 km 1 hr version on IBM SP– Probably by summer 2000– 3-d variational analysis– Cloud/hydrometeor analysis using satellite combined
with explicit cloud fcsts in RUC-2• Later, assimilation of new data sets: radar, sfc cloud obs, 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.
– 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
– 13-15 km/60 level - 2001
• Applications to air quality, coupled air chemistry?
• Extensive NAOS observation sensitivity tests
• WRF version of RUC
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 5-8 km scale– 30-min cycle or finer?
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Quasi-isentropic option for WRF non-hydrostatic model
Breaking mountain wave simulation - 2 km horizontal resolutionSigma-z version Quasi-isentropic version
Thick -
Thin - coordinate surfaces
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Rapid Update Cycle – Present and Next Version1999 Operations 2000-01 Operations
Resolution 40 km, 40levels 2013-15 km, 40 50-60 levels
Analysis Optimal interpolation on 3-d variational technique on generalized on generalized surfaces surfaces, hydrometeor analysis w/
GOES…, use raw instead of interp. obsAssimilation Intermittent 1-h cycle Intermittent 1-h cycle
Stable clouds Mixed-phase cloud microphysics MM5), Improved microphysics, / precipitation explicit fcst of cloud water, rain water, addition of drizzle
snow, ice, graupel, no. concentration of ice particles
Sub-grid-scale Grell (1993) Modified Grell, scale dependence, precipitation shallow convection, interaction w/
cloud microphysics Turbulence Burk-Thompson explicit TKE scheme Refined Burk-Thompson or e-
Radiation MM5 LW/SW scheme, f(hydrometeors) Refined MM5 scheme
Land-sfc processes 6-level soil/veg model (Smirnova, Add vertical soil type variability, 1997, 1999) w/ frozen soil, 2-layer snow improved cold season processes
Sfc conditions Daily 50km SST/14 km LST, Combine sat Tskin, use 3-d soil type 0.14 monthly NDVI veg frac, cycled soil moisture/temp, snow depth/temp
Feedback
• Send feedback/questions on RUC performance to the RUC discussion forum.
• Invite us to workshops.
http://maps.fsl.noaa.gov/forum/eval
