stan benjamin noaa forecast system lab boulder, colorado stan.benjamin@noaa
DESCRIPTION
Rainer Bleck- Los Alamos John M. Brown- NOAA/FSL Kevin Brundage “ Dezso Devenyi “ Georg Grell “ Dongsoo Kim “ Geoff Manikin- NCEP/EMC Barry Schwartz- NOAA/FSL Tanya Smirnova“ Tracy Lorraine Smith“ Steve Weygandt“. Stan Benjamin NOAA Forecast System Lab - PowerPoint PPT PresentationTRANSCRIPT
Mesoscale weather prediction with the RUC hybrid isentropic-sigma
coordinate model and data assimilation system
Stan BenjaminNOAA Forecast System LabBoulder, Colorado
[email protected] http://ruc.fsl.noaa.gov
Rainer Bleck - Los AlamosJohn M. Brown- NOAA/FSLKevin Brundage “Dezso Devenyi “Georg Grell “Dongsoo Kim “Geoff Manikin - NCEP/EMCBarry Schwartz - NOAA/FSLTanya Smirnova “Tracy Lorraine Smith “Steve Weygandt “
Symposium - 50th Anniversary - Operational NWP
15 June 2004
2
Rapid Update Cycle - An unusual branch of the operational NWP
family genealogy
- Use of a quasi-isentropic vertical coordinate for model prediction and data assimilation - Numerical weather prediction and data assimilation on a sub-12h cycle (currently 1 h)
3
~1985• FAA-sponsored Aviation Weather Forecasting Task Force
• Recommendations:• Promote additional automated aircraft reports from commercial aircraft• Develop high-frequency NWP system
• NMC (now NCEP) / PROFS (now NOAA-FSL) agreement on development of ‘high-frequency’ NWP system
(Ron McPherson, Tom Schlatter, Sandy MacDonald)
• Assimilation of anticipated increase of hourly 3-d observations
• wind profilers, commercial aircraft, satellite, radar, surface
4
Choices for vertical coordinate foratmospheric prediction models
• Height• Pressure• Entropy
Potential temperature - = T (1000/p)R/Cp
Isentropic weather maps- commonly used in US in late 1930s
Rossby et al. 1937- plagued by reported Montgomery
streamfunction - inaccurate integration of
hydrostatic equation
5
• Eliassen and Raustein – 1968But what to do about that lower boundary condition …
• Bleck – 1974, 1977 (carrying sfc as prognostic variable)Now how to resolve the planetary boundary layer …
Modeling efforts with pure isentropic vertical coordinates
Hybrid isentropic-sigma models
• Bleck – 1978• Deaven – 1976• Gall – 1972• Uccellini et al. – 1979• Johnson et al. - 1993• Konor and Arakawa – 1997. . . . .
6
1990 FSL/Bleck modelusing Uccellini-typehybrid - model
Bleck and Benjamin – 1993- MWRBenj, Grell, Brown, Smirnova, Bleck, 2004 – MWRBleck and Boudra – 1981 - hybrid-isopycnic modelGeneralized vertical coordinate - Used in all oper RUC versions
7
Montevideo south
Vertical section through HYCOM solution. Heavy black lines: coordinate surfaces. Shaded contours: potential density
Hybrid (isopycnic-sigma) Ocean Community Model – HYCOM - U. Miami, Los Alamos Natl. Lab - from Rainer Bleck
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Why even try to use a quasi-Lagrangian vertical coordinate?
• Adaptive higher vertical resolution - vertical gradient of wind, moisture, chemical species …• Less cross-coordinate vertical transport
3-d fluid motion resolved largely by 2-d transport - Less non-physical diffusion, less aphysical source of entropy in numerical model
(Bleck…, Johnson 1997)
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Quasi-horizontal / Cartesian vs.
functional spatial definitions
Isobaric Isentropic
Reference v values (220-500K) pre-assigned to each of RUC levels.
RUC generalized vertical coordinate- configured as a hybrid isentropic-sigma
coordinate
Cross section A Vertical coordinate definition - examples: Sigma-pressurep(k), ptop (fixed) (+psfc) (adaptive) p(i,j,k)
Generalized -pmin(k), v- ref(k) (fixed) (+psfc , v) (adaptive)
p(i,j,k)
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0sp p ps
t s s s s
V
Continuity equation(inviscid, adiabatic conditions in generalized coordinate s)
Pressure ~0 0
Isentropic 0 ~ 0
Mass conv/div
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RUC 20km model forecast - initial conditions – 12z
4 February 2001
Tropopause level (hPa) - defined as potential vorticity (PV) unit = 2
12h forecast 24h forecast
36h forecast
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Vertical cross-sections from RUC 36-h forecasts- valid 00z 6 Feb 2001
Potential vorticity
Vertical velocity(x 10 b/s)
Relative humidity
N S
N S
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e conservation testsHistogram of e - e (proxy)
RUC model with a) coord
(control) b) coord (fixed) much better moist reversibility w/ model
24h forecastInit 00z 8 Feb 2001
(test concept - Johnson -1997)
e - e (proxy) (K)
– grid
pts
at l
ev 4
0
MWR article – Feb 2004-Mesoscale wx predW/ RUC hybrid model -Benj, Grell, Brown, Smirnova, Bleck
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Analysis
- adaptive 3-d correlation structures and analysis increments, esp. near baroclinic zones, vertical spreading = f()- 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)
Advantages of Coordinates for Data
AssimilationOI, 3dvar techniques in coordinate developed for RUC analysis
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~1985• FAA-sponsored Aviation Weather Forecasting Task Force
• Recommendations:• Promote additional automated aircraft reports from commercial aircraft• Develop high-frequency NWP system
• NMC (now NCEP) / PROFS (now NOAA-FSL) agreement on development of ‘high-frequency’ NWP system
(Ron McPherson, Tom Schlatter, Sandy MacDonald)
• Assimilation of anticipated increase of hourly 3-d observations
• wind profilers, commercial aircraft, satellite, radar, surface
NCEP model hierarchy – RUC (1h frequency) Eta (6h) Global (6h)
The 1-h Version of the Rapid Update Cycle at
NCEP
Figure 1. Data ingest, analysis, and forecast cycle for the Rapid Update Cycle (RUC) NWP Model.
12 hr. fcst
3 hr. fcst
00 01 02 03 04 05 06 07 08 09 10 11 12 (UTC)
Analysis times
3 hr. fcst
12 hr. fcst To 15Z
3 hr. fcst3 hr. fcst
12 hr. fcst To 18Z
3 hr. fcst3 hr. fcst
12 hr. fcst
3 hr. fcst3 hr. fcst
To 21Z
1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr.
DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA
fcst fcst fcst fcst fcst fcst fcst fcst fcst fcst fcst fcst
To 12Z12 hr. fcst
3 hr. fcst
00 01 02 03 04 05 06 07 08 09 10 11 12 (UTC)
Analysis times
3 hr. fcst
12 hr. fcst To 15Z
3 hr. fcst3 hr. fcst
12 hr. fcst To 18Z
3 hr. fcst3 hr. fcst
12 hr. fcst
3 hr. fcst3 hr. fcst
To 21Z
1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr.
DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA
fcst fcst fcst fcst fcst fcst fcst fcst fcst fcst fcst fcst
To 12Z12 hr. fcst
3 hr. fcst
00 01 02 03 04 05 06 07 08 09 10 11 12 (UTC)
Analysis times
3 hr. fcst
12 hr. fcst To 15Z
3 hr. fcst3 hr. fcst
12 hr. fcst To 18Z
3 hr. fcst3 hr. fcst
12 hr. fcst
3 hr. fcst3 hr. fcst
To 21Z
1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr.
3 hr. fcst
12 hr. fcst To 15Z
3 hr. fcst3 hr. fcst
12 hr. fcst To 18Z
3 hr. fcst3 hr. fcst
12 hr. fcst
3 hr. fcst3 hr. fcst
To 21Z
1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr.
DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA
fcst fcst fcst fcst fcst fcst fcst fcst fcst fcst fcst fcst
To 12Z12 hr. fcst
3 hr. fcst
00 01 02 03 04 05 06 07 08 09 10 11 12 (UTC)
Analysis times
3 hr. fcst
12 hr. fcst To 15Z
3 hr. fcst3 hr. fcst
12 hr. fcst To 18Z
3 hr. fcst3 hr. fcst
12 hr. fcst
3 hr. fcst3 hr. fcst
To 21Z
1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr.
3 hr. fcst
12 hr. fcst To 15Z
3 hr. fcst3 hr. fcst
12 hr. fcst To 18Z
3 hr. fcst3 hr. fcst
12 hr. fcst
3 hr. fcst3 hr. fcst
To 21Z
1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr. 1 hr.
DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA
fcst fcst fcst fcst fcst fcst fcst fcst fcst fcst fcst fcst
To 12Z
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Model/ Horizontal No. AssimilationImplement atAssim resolution vert frequencyNMC/NCEPsystem levels
RUC1 60 km 25 3 h 1994
RUC2 40 km 40 1 h 1998Added
• state-of-art model physics – convection, mixed-phase cloud, land-sfc• assimilation of surface obs • hourly cycling of
• 5-type hydrometeor cloud variables, • land-surface variables (6 levels, snow variables)
RUC20 20 km 50 1 h2002
Added assimilation of GOES cloud-top data
RUC development – ongoing interaction with NCEP and NCAR
Data Type ~Number Freq.Rawinsonde 80/12hNOAA 405 MHz profilers 31 / 1hVAD winds (WSR-88D radars) 110-130 / 1h Aircraft (ACARS) (V,temp) 1800-5500 / 1hSurface/METAR (T,Td,V,p) 1500-1700 / 1hBuoy/ship 100-150 / 1hGOES precipitable water 1500-3000 / 1hGOES cloud drift winds 1000-2500 / 1hGOES cloud-top pressure/temp ~10km res / 1hSSM/I precipitable water 1000-4000 / 6h In testing at FSL – early 2004GPS precipitable water ~250 / 1hRadar reflectivity / lightning 4 kmMesonet 3000-5000 / 1hMETAR cloud/vis/wx obs / 1h
Obs Data for RUC
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RUC20Wind forecastAccuracy
-Sept-Dec2002
Verification against rawinsonde data over RUC domainRMS vector difference (forecast vs. obs)
RUC is able to use recent obs to improve forecast skill down to 1-h projection for winds
1 3 6 912
Analysis~ ‘truth’
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Quasi-isentropic option for non-hydrostatic model
Breaking mountain wave simulation - 2 km horizontal resolutionSigma-z version Quasi-isentropic version
Thick -
Thin - coordinate surfaces
Zuwen He,2002 Ph.D.U. Miami
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1985
Anticipated use for RUC
- Aviation community
2004
Current users of RUC data
- Aviation community air traffic mgmt
- NCEP Storm Prediction Center- NWS Forecast Offices- Private forecasting- Air quality- Energy industry. . .
Changes in • Number of NWP users• Frequency of access to NWP data• Ability to use shorter- and longer-duration NWP data• User requrements for forecast accuracy, incl. short-range
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2004-2007• Assimilation of surface cloud obs/ current weather/vis, radar reflectivity, GPS …• 13km RUC (in testing at FSL) • WRF-based “Rapid Refresh”, replacing current RUC model• More common software (model, data assimilation) for replacements to RUC, Eta, Hurricane models.
• NCEP, NCAR, NOAA labs, AFWA…
Beyond (IMHO)• 15-30 min continuous update cycle• Global update cycle• Ensemble update cycles• Use of quasi-Lagrangian vertical coordinate models – ocean, atmosphere
RUC changes