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John Brown NOAA Forecast Systems Lab 19 April 2001. RUC Development - Applications to National C/V. Key goals for 20km RUC. Take advantage of increased computer power  higher spatial resolution Improve RUC performance for QPF, especially for convective precipitation

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ruc development applications to national c v

John Brown

NOAA Forecast Systems Lab

19 April 2001

RUC Development- Applications to National C/V

key goals for 20km ruc
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 assimilation
  • Eliminate bugs
rapid update cycle present and next version
Rapid Update Cycle – Present and Next Version

1999-2000 Operations Spring 2001 Operations

Resolution 40 km, 40 q/s levels 20 km, 50q/s levels

Analysis Optimal interpolation on 3-d variational technique on generalized

on generalized q/s surfaces q/s surfaces, hydrometeor analysis w/

GOES…, use raw instead of interp. obs

Assimilation Intermittent 1-h cycle Intermittent 1-h cycle

Stable 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,

precipitationshallow convection, detrainment of

cloud water to microphysics

Turbulence Burk-Thompson explicit TKE scheme Burk-Thompson, e- parameterization

under development

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 cycle

Sfc 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 6h

Forecast duration Hourly output to  3h, 12h fcst every 3h Hourly output to  6 h, 12h fcst every 3h

20km ruc maps topography
20km RUC/MAPS topography

Subset of full domain

slide5

40km RUC

40 levels

20km RUC

50 levels

RUC native coordinate levels

10 new levels

7 – upper levels – 330 – 500 K

3 – lower levels – 270 – 290 K

rapid update cycle present and next version1
Rapid Update Cycle – Present and Next Version

1999-2000 Operations Spring 2001 Operations

Resolution 40 km, 40 q/s levels 20 km, 50q/s levels

Analysis Optimal interpolation on 3-d variational technique on generalized

on generalized q/s surfaces q/s surfaces, hydrometeor analysis w/

GOES…, use raw instead of interp. obs

Assimilation Intermittent 1-h cycle Intermittent 1-h cycle

Stable 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,

precipitationshallow 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 cycle

Sfc 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 6h

Forecast duration Hourly output to  3h, 12h fcst every 3h Hourly output to  6 h, 12h fcst every 3h

slide7

400

500

600

700

800

900

1000

400

500

600

700

800

900

1000

400

500

600

700

800

900

1000

Riverton, WY

sounding

12 UTC 18 Aug 2000

OI

3DVAR

OBS

data for 20 km ruc 3dvar at ncep
Data for 20-km RUC 3dVAR at NCEP

Data Type ~Number Freq.

Rawinsonde (inc. special obs) 80 /12h

NOAA 405 MHz profilers 31 / 1h (better use)

VAD winds (WSR-88D radars) 110-130 / 1h (3h currently)

Aircraft (ACARS) (V,temp) 1400-4500 / 1h

Surface/METAR - land (V,psfc,T,Td) 1500-1700 / 1h

Buoy 80-150 / 1h

GOES precipitable water 1500-3000 / 1h (closer fit)

GOES cloud drift winds 1000-2500 / 1h (closer fit)

GOES cloud-top pressure ~40km res / 1h

SSM/I precipitable water 1000-4000 /2-6h

GPS precipitable water ~65 / 1h

Boundary-layer (915 MHz) profilers ~24 / 1h

RASS (WPDN and PBL) 15 / 1h

Ship reports 10s / 3h

Reconnaissance dropwinsonde a few / variable

New for 20km RUC at NCEP

initial ruc cloud analysis technique
Initial RUC cloud analysis technique

Goal – Improve RUC precipitation, cloud, icing forecasts

  • 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
slide10

Verification

Cloud-top pressure

based on NESDIS product

3h 20km RUC cloud-top fcst

w/ GOES cloud assim

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

slide11

Cloud water analysis – cross-section

Without GOES With GOES

Ice mixing ratio analysis – cross-section

Without GOES With GOES

ruc cloud analysis status
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
rapid update cycle present and next version2
Rapid Update Cycle – Present and Next Version

1999-2000 Operations Spring 2001 Operations

Resolution 40 km, 40 q/s levels 20 km, 50q/s levels

Analysis Optimal interpolation on 3-d variational technique on generalized

on generalized q/s surfaces q/s surfaces, hydrometeor analysis w/

GOES…, use raw instead of interp. obs

Assimilation Intermittent 1-h cycle Intermittent 1-h cycle

Stable 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,

precipitationshallow convection, detrainment of

cloud water to microphysics

Turbulence Burk-Thompson explicit TKE scheme Burk-Thompson, e- parameterization

under development

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 cycle

Sfc 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 6h

Forecast duration Hourly output to  3h, 12h fcst every 3h Hourly output to  6 h, 12h fcst every 3h

key changes in 20km ruc forecast model for qpf
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
cloud and precipitation microphysics
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

mm5 ruc cloud and precipitation microphysics scheme
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 -40C < T  0C.

Inverse exponential (Marshall-Palmer) particle size distribution

assumed.

slide18

St. Lawrence valley/ New England ice storm - 9h RUC2 fcst valid 2100z 9 Jan 98

N-S cross sections of RUC2 microphysics

Water vapor mixing ratio / q

Cloud water mixing ratio

| YUL/Montreal

Graupel mixing ratio

Rain water mixing ratio

Excessive graupel

production

principal changes to exmoisg
PRINCIPAL CHANGES TO EXMOISG

Bug 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 < 0C)

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

changes to mm5 ruc microphysics with 20km ruc
Changes to MM5/RUC microphysics with 20km RUC
  • Result:
  • More realistic supercooled liquid water
  • Improved precip type

Bug fixes

Changes for formation of ice and graupel

- result – less “ice friendly”

Change in time step from 10 min to 2 min

40km operational RUC at NCEP

20km test RUC w/ microphysics fixes

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

outlook for ruc microphysics
Outlook for RUC microphysics

NCEP 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.

ruc maps land surface process parameterization
RUC/MAPSLand-surfaceProcessParameterization

Purpose –

Improve near-sfc,

precip, cloud fcsts

Ongoing cycle

of soil moisture,

soil temp, snow

cover/depth/temp)

2-layer snow model

  • New in 20km
  • change in thermal conductivity – better diurnal cycle
  • frozen soil physics, 2-layer snow model
slide23

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 field

9 December 1999 2200 UTC

slide24

RUC-20

USAF

Snow water equivalent depth

(RUC-20)

Snow depth (USAF)

Snow coverage (NESDIS)

28 November 2000

2000 UTC

NESDIS

further modifications of ruc land surface model
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)
slide26

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

changes to surface input fields in ruc 20
CHANGES TO SURFACE INPUT FIELDS IN RUC-20
  • Soil type
    • 1-km CONUS-SOIL, 16 classes
    • ( 1-degree Zobler soil types in current RUC)
  • Vegetation type
    • 1-km data, 24 USGS classes
    • (1-degree vegetation types in current RUC)
  • Albedo
    • 0.140 monthly data, NESDIS
    • (1-degree seasonal climatology in current RUC)
  • Sea-surface temperatures
    • daily 50km analyses
  • Vegetation fraction
    • 0.140 data – NESDIS – NDVI-based
slide28

1 2 3 4 5 6 7 8 9 10

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

slide29

Vegetation types in 40km RUC

(12 classes)

High-resolution vegetation types in 20km RUC

(24 USGS classes)

slide30

Albedo in 40 km RUC

Albedo in 20 km RUC

-monthly NESDIS data

18 May 2000

ruc cloud base height
RUC Cloud-Base Height
  • Height above surface where

qc + qi first exceeds 10-3g/kg

ruc derived visibility
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.

slide33

RUC visibility forecasts

20 km RUC

3h fcst

40 km RUC

3h fcst

28 August 2000

15 UTC

Vis  1 mi

Vis – 3-5 mi

GOES visible image

summary the 20km ruc
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

ruc c v future work
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.

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