RUC Development- Applications to National C/V

John BrownNOAA Forecast Systems Lab

19 April 2001

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Key goals for 20km RUC

• Take advantage of increased computer power higher spatial resolution

• Improve RUC performance for QPF, especially for convective precipitation

• Improve RUC initial conditions------------------------------------------------------------Incorporate new advances in model and assimilationEliminate bugs

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1999-2000 Operations Spring 2001 Operations

Resolution 40 km, 40levels 20 km, 50 levelsAnalysis Optimal interpolation on 3-d variational technique on generalized

on generalized surfaces surfaces, hydrometeor analysis w/ GOES…, use raw instead of interp. obs

Assimilation Intermittent 1-h cycle Intermittent 1-h cycleStable clouds Mixed-phase cloud microphysics MM5), New version of MM5/RUC / precipitation explicit fcst of cloud water, rain water, microphysics (FSL and NCAR),

snow, ice, graupel, much shorter microphysics time step no. concentration of ice particles

Sub-grid-scale Grell (1993) New Grell scheme w/ ensemble cloud, precipitation shallow convection, detrainment of

cloud water to microphysics Turbulence Burk-Thompson explicit TKE scheme Burk-Thompson, e- parameterization

under developmentRadiation MM5 LW/SW scheme, f(hydrometeors) MM5 scheme with fix to SW lag error

Land-sfc processes 6-level soil/veg model (Smirnova, 2-layer snow model, 1997, 2000) w/ frozen soil, 1-layer snow improved cold season processes,

improved diurnal cycleSfc conditions Daily 50km SST/14 km LST, Add high-res USGS land-use/soil type,

0.14 monthly NDVI veg frac, cycled soil albedo moisture/temp, snow depth/temp

Boundary conds Eta model initialized every 12h Eta model initialized every 6hForecast duration Hourly output to 3h, 12h fcst every 3h Hourly output to 6 h, 12h fcst every 3h

Rapid Update Cycle – Present and Next Version

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Subset of full domain 20km RUC/MAPS topography

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40km RUC40 levels

20km RUC50 levels

10 new levels7 – upper levels – 330 – 500 K3 – lower levels – 270 – 290 K

RUC native coordinate levels

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1999-2000 Operations Spring 2001 Operations

Resolution 40 km, 40levels 20 km, 50 levelsAnalysis Optimal interpolation on 3-d variational technique on generalized

on generalized surfaces surfaces, hydrometeor analysis w/ GOES…, use raw instead of interp. obs

Assimilation Intermittent 1-h cycle Intermittent 1-h cycleStable clouds Mixed-phase cloud microphysics MM5), New version of MM5/RUC / precipitation explicit fcst of cloud water, rain water, microphysics (FSL and NCAR),

snow, ice, graupel, much shorter microphysics time step no. concentration of ice particles

Sub-grid-scale Grell (1993) New Grell scheme w/ ensemble cloud, precipitation shallow convection, detrainment of

cloud water to microphysics Turbulence Burk-Thompson explicit TKE scheme Burk-Thompson

Radiation MM5 LW/SW scheme, f(hydrometeors) MM5 scheme with fix to SW lag error

Land-sfc processes 6-level soil/veg model (Smirnova, 2-layer snow model, 1997, 2000) w/ frozen soil, 1-layer snow improved cold season processes,

improved diurnal cycleSfc conditions Daily 50km SST/14 km LST, Add high-res USGS land-use/soil type,

0.14 monthly NDVI veg frac, cycled soil albedo moisture/temp, snow depth/temp

Boundary conds Eta model initialized every 12h Eta model initialized every 6hForecast duration Hourly output to 3h, 12h fcst every 3h Hourly output to 6 h, 12h fcst every 3h

Rapid Update Cycle – Present and Next Version

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OI

3DVAROBS

Riverton, WYsounding

12 UTC 18 Aug 2000

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Data for 20-km RUC 3dVAR at NCEPData Type ~Number Freq.Rawinsonde (inc. special obs) 80 /12hNOAA 405 MHz profilers 31 / 1h (better use)VAD winds (WSR-88D radars) 110-130 / 1h (3h currently)Aircraft (ACARS) (V,temp) 1400-4500 / 1hSurface/METAR - land (V,psfc,T,Td) 1500-1700 / 1hBuoy 80-150 / 1hGOES precipitable water 1500-3000 / 1h (closer fit)GOES cloud drift winds 1000-2500 / 1h (closer fit)GOES cloud-top pressure ~40km res / 1hSSM/I precipitable water 1000-4000 /2-6hGPS precipitable water ~65 / 1hBoundary-layer (915 MHz) profilers ~24 / 1hRASS (WPDN and PBL) 15 / 1hShip reports 10s / 3hReconnaissance dropwinsonde a few / variable

New for 20km RUC at NCEP

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Initial RUC cloud analysis technique

• Uses GOES/NESDIS cloud-top pressure (sounder-based)

• Uses RUC 1-h hydrometeor fcst (cloud water, ice, snow/rain/graupel) as first guess

• Performs cloud clearing and cloud building

• Uses observations to build 3-d cloud yes/no/unknown field• surface cloud obs, radar reflectivity assimilable with same code structure/logic

Goal – Improve RUC precipitation, cloud, icing forecasts

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3h 20km RUC cloud-top fcstw/ GOES cloud assim

VerificationCloud-top pressurebased on NESDIS product

Effect of GOES data on 3-h RUC cloud forecasts

2100 UTC Wed 21 March 2001 3h 40km RUC cloud-top fcst

No GOES cloud assim

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Cloud water analysis – cross-sectionWithout GOES With GOES

Ice mixing ratio analysis – cross-sectionWithout GOES With GOES

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RUC cloud analysis status• Technique developed combining GOES sounder-based

cloud-top data with RUC explicit cloud forecasts• Current version – impact on forecasts

– Cloud top – more improvement in 1-h forecasts, smaller but consistent improvement in 12-h cloud-top forecasts

– Slight improvement in RH bias and standard deviation, especially in mid-troposphere

– Slight improvement in QPF at larger thresholds

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1999-2000 Operations Spring 2001 Operations

Resolution 40 km, 40levels 20 km, 50 levelsAnalysis Optimal interpolation on 3-d variational technique on generalized

on generalized surfaces surfaces, hydrometeor analysis w/ GOES…, use raw instead of interp. obs

Assimilation Intermittent 1-h cycle Intermittent 1-h cycleStable clouds Mixed-phase cloud microphysics MM5), New version of MM5/RUC / precipitation explicit fcst of cloud water, rain water, microphysics (FSL and NCAR),

snow, ice, graupel, much shorter microphysics time step no. concentration of ice particles

Sub-grid-scale Grell (1993) New Grell scheme w/ ensemble cloud, precipitation shallow convection, detrainment of

cloud water to microphysics Turbulence Burk-Thompson explicit TKE scheme Burk-Thompson, e- parameterization

under developmentRadiation MM5 LW/SW scheme, f(hydrometeors) MM5 scheme with fix to SW lag error

Land-sfc processes 6-level soil/veg model (Smirnova, 2-layer snow model, 1997, 2000) w/ frozen soil, 1-layer snow improved cold season processes,

improved diurnal cycleSfc conditions Daily 50km SST/14 km LST, Add high-res USGS land-use/soil type,

0.14 monthly NDVI veg frac, cycled soil albedo moisture/temp, snow depth/temp

Boundary conds Eta model initialized every 12h Eta model initialized every 6hForecast duration Hourly output to 3h, 12h fcst every 3h Hourly output to 6 h, 12h fcst every 3h

Rapid Update Cycle – Present and Next Version

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Key changes in 20km RUC forecast model for QPF

• Fixes to bugs in vertical advection of moisture

• Fix to bug for effect of vertical velocity on convective precipitation

• 20km/50 level resolution – resolved precipitation improved – grid volumes are now ~5 times smaller

• Improved land-surface parameterization

• New ensemble cumulus parameterization – Grell

• Revised version of MM5/RUC microphysics

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Deep convection parameterization – new Grell scheme

• Inclusion of cloud water/ice detrainment (interaction with microphysics scheme)

• Ensemble of closure and feedback assumptions

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Cloud and precipitation microphysics

New version of Reisner et al (1998, Quart. J. Roy. Meteor. Soc.) "option 4" mixed-phase, bulk microphysics scheme

("EXMOISG")

Initially developed at NCAR for MM5, and implemented with RUC-2 at NCEP in April 1998

New version removes the most egregious faults with version of EXMOISG currently in the operational RUC-2 at NCEP

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MM5/RUC Cloud and precipitation microphysics scheme

Main aspects of EXMOISG scheme Predicted quantities: - Mixing ratios of

water vapor cloud liquid water

rain water cloud ice snow graupel

- Number concentration of cloud ice

Water and ice permitted to coexist for -40C < T 0C.

Inverse exponential (Marshall-Palmer) particle size distribution assumed.

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St. Lawrence valley/ New England ice storm - 9h RUC2 fcst valid 2100z 9 Jan 98N-S cross sections of RUC2 microphysics

| YUL/Montreal| YUL/Montreal

Water vapor mixing ratio / Cloud water mixing ratio

Graupel mixing ratioRain water mixing ratioExcessive graupel production

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PRINCIPAL CHANGES TO EXMOISGBug fixes (including one major one involving graupel at cold temps)

Reduce interval between calls to EXMOISG

Formation of new ice crystals ("nucleation") constrained via "Cooper curve" rather than by "Fletcher Curve" (both empirical)

Improve consistency of ice particle number calculations.

Different criteria for formation of graupel as result of collisions between snowflakes and drops of cloud liquid water (temp < 0C)

Allow larger concentrations of cloud water to be present before raindrops are formed

Very small rainwater contents are regarded as being composed of drizzle-sized drops

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Changes to MM5/RUC microphysics with 20km RUC

SW-NE vertical cross-section across WA /Olympic Peninsula into BC and Alberta - 12h forecast valid 0300z 5 January 2001

40km operational RUC at NCEP

20km test RUC w/ microphysics fixes

Bug fixesChanges for formation of ice and graupel - result – less “ice friendly”Change in time step from 10 min to 2 min

Result:• More realistic supercooled liquid water• Improved precip type

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Outlook for RUC microphysicsNCEP implementation -- Ongoing validation of real-time QPF, precipitation-type forecasts

Longer term -- Continued work to improve model guidance for icing prediction

will be needed well into the future. -- Possible further upgrade to EXMOISG in RUC within ~ 12 months -- Use of EXMOISG in RUC cloud assimilation -- Continued collaboration with NCAR for MM5, RUC and WRF application -- Further improvements for air quality and regional climate applications (e.g., air chemistry, radiation, land surface)

NOAA-NCAR collaboration has been vital to improving EXMOISG.

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Purpose –Improve near-sfc,precip, cloud fcsts

Ongoing cycleof soil moisture,soil temp, snowcover/depth/temp)

2-layer snow model

RUC/MAPSLand-surface

ProcessParameterization

New in 20km- change in thermal conductivity – better diurnal cycle- frozen soil physics, 2-layer snow model

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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) 9 December 1999 1800 UTC

NESDIS snow cover field9 December 1999 2200 UTC

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Snow water equivalent depth (RUC-20)Snow depth (USAF)Snow coverage (NESDIS) 28 November 2000 2000 UTC

RUC-20

NESDIS

USAF

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Further modifications of RUC land-surface model

• Johansen (1975) parameterization of thermal conductivity in soil – improvements against the previous parameterization (McCumber 1980) especially for saturated soils

• Refreezing of 13% of melted water inside the snow pack (Koren et al. 1999)

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Improved 1-d (PILPS 2d – Valdai, Russia) total runoff and snow water equivalent forecasts with improved snow and soil physics in MAPS land-surface model

Total runoff

Snow water equivalent

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CHANGES TO SURFACE INPUT FIELDS IN RUC-20

• Soil type1-km CONUS-SOIL, 16 classes( 1-degree Zobler soil types in current RUC)

• Vegetation type1-km data, 24 USGS classes(1-degree vegetation types in current RUC)

• Albedo0.140 monthly data, NESDIS(1-degree seasonal climatology in current RUC)

• Sea-surface temperaturesdaily 50km analyses

• Vegetation fraction0.140 data – NESDIS – NDVI-based

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1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10

Soil types in 40 km RUC Soil types in 20 km RUCSoil types in 40 km RUC Soil types in 20 km RUC

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Vegetation types in 40km RUC

(12 classes)

High-resolution vegetation High-resolution vegetation types in 20km RUC types in 20km RUC (24 USGS classes)(24 USGS classes)

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Albedo in 40 km RUCAlbedo in 40 km RUC Albedo in 20 km RUCAlbedo in 20 km RUC-monthly NESDIS data-monthly NESDIS data

18 May 200018 May 2000

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RUC Cloud-Base Height

• Height above surface where

qc + qi first exceeds 10-3g/kg

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RUC derived visibility

Relative humidity and hydrometeors are considered separately:

Hydrometeors: Stoelinga and Warner (1999) with

ad hoc addition of graupel

Relative humidity: > 95% visibility of 8 km

< 15% visibility of 60 km.

Lowest visibility value is used.

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40 km RUC3h fcst

20 km RUC3h fcst

28 August 200015 UTC

GOES visible image

Vis 1 mi

Vis – 3-5 mi

RUC visibility forecasts

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Summary - the 20km RUC• Schedule for implementation

– April 2001 – Get new code/scripts running at NCEP – test mode• Available for 20km RUC seminars at NWS Regions, NCEP Centers

– May – Real-time testing at NCEP – evaluation in field, retrospective runs– June – Consideration for CAFTI approval– Late June – early July - planned operational implementation

• 20 km/50 level 1 hr version– with model improvements including cloud microphysics, convection, land-

surface, hourly fcsts out to 6h– 3-d variational analysis, cloud/hydrometeor analysis using satellite

combined with explicit cloud fcsts in RUC– Improvements in warm- and cold-season precipitation and cloud/icing

forecasts, also in surface forecasts

RUC web site - http://ruc.fsl.noaa.gov - 20km test RUC products

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RUC C&V Future Work

* Understand and correct deficiencies in model

physics (particularly PBL, microphysics). [ongoing]

* Translation algorithms– development, evaluation [ongoing]

* Addition of aerosols, simple chemistry. [2002 and later]

* Use of ensembles => probability forecasts of restrictive

conditions [future]

* Shift to WRF as rapid-update medium [future]

…

All activities will involve interactions with other groups.