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Operational Use of the Rapid Update Cycle

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Operational Use of the Rapid Update Cycle. COMET NWP Symposium. 30 March 2000 ... Geoff Manikin NCEP/EMC. Data cutoff - 20 min, 2nd run at 55 min at 0000, 1200 UTC ... – PowerPoint PPT presentation

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Title: Operational Use of the Rapid Update Cycle


1
Operational Use of the Rapid Update Cycle
Stan Benjamin mgmt, anx, model John Brown
model physics Kevin Brundage web,NCEP Georg
Grell model Dongsoo Kim sat data in anx Barry
Schwartz verif, obs Tanya Smirnova model,
land-sfc Tracy Smith verif, obs Geoff Manikin
NCEP/EMC
Stan Benjamin - NOAA/FSL benjamin_at_fsl.noaa.gov htt
p//maps.fsl.noaa.gov - RUC/MAPS web page
  • COMET NWP Symposium
  • 30 March 2000

2
The 1-h Version of the RUC
Data cutoff - 20 min, 2nd run at 55 min at
0000, 1200 UTC
3
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

4
RUC vector (m/s) forecast error 0000 UTC 27 Jan
98 250 hPa
9h init 15z
12h init 12z
6h init 18z
3h init 21z
5
What Runs Where
  • Rapid Update Cycle (RUC)
  • Operational Version at NCEP
  • Mesoscale Analysis and Prediction System (MAPS)
  • Experimental Version at NOAA/ERL/FSL
  • Backup RUC
  • Advanced, hardened version running at FSL
  • Used after NCEP fire (1 Oct 15 Nov), during
    NCEP outages since then
  • (Essentially the same software.
  • New capabilities tested first in MAPS at FSL)

6
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
  • Other AWRP PDTs icing, turbulence,
    AGFS/ADDS/RTVS, convective weather, winter weather

7
NWS Forecast Discussion Use of RUC - Feb 1999
Feb 2000
200-500 100-199 40-99 20-39 10-19
8
RUC/MAPS web page - http//maps.fsl.noaa.gov

9
40km RUC topography
10
Hourly Data for 40 km RUC-2
Data Type Number Freq. Use Rawinsonde (inc.
special obs) 80 /12h NCEP and
FSL WPDN/NPN profilers 31 / 1h NCEP
and FSL - 405 MHz Boundary layer profilers
15 / 1h FSL only RASS (WPDN and PBL)
15 / 1h FSL only VAD winds (WSR-88D) 110-130 /
1h NCEP FSL Aircraft (ACARS)(V,temp)
700-3000 / 1h NCEP and FSL Surface - land
(V,psfc,T,Td) 1500-1700 / 1h NCEP and
FSL Buoy 100-200 / 1h NCEP and FSL
not used since 1/99 in RUC or EDAS pending QC
issues
Yellow items new for RUC-2
11
Hourly Data for 40 km MAPS/RUC-2 (cont).
Data Type Number Freq. Use GOES precipitable
water 1000-2500 / 1h NCEP and FSL GOES
high-density cloud drift winds (IR, VIS, WV
cloud top) 1000-2500 / 3h NCEP and FSL SSM/I
precipitable water 1000-4000 /2-6h NCEP only Ship
reports 10s / 3h NCEP
only Reconnaissance dropwinsonde a few /
variable NCEP only
Yellow items new for RUC-2
Real-time observation counts at
http//maps.fsl.noaa.gov for RUC-2 and 40-km MAPS
12
Advantages of q Coordinates for Data Assimilation
Analysis - adaptive 3-d correlation structures
and analysis increments, esp. near baroclinic
zones, vertical spreading f(q) - 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)
13
RUC hybrid-b levels - cross-section
Hybrid-b levels - solid q levels (every 6 K) -
dashed
No discontinuities at q/s transitions
14
RUC generalized vertical coordinate
Cross section A
Cross section B
A
Reference ?v values (220-450K) assigned to each
of (40) RUC levels. More generalized levels
become terrain-following levels in warmer
parts of domain/times of year
B
1800 UTC 24 February 2000 Surface ?v
15
Solution of continuity equation
S generalized vertical coordinate surfaces

Solve mass convergence
?0 0 for s? 0 ?0
for ss
16
Effect of vertical coordinate on frontal features
Turbulence diagnostic at 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
17
Rapid Update Cycle Present and Next Version
1999 Operations 2000-01 Operations Resolution
40 km, 40 q/s levels 20?15 km, 40 ? 50-60 q/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), 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,
2-layer snow, improved hi-res land use,
1997, 1999) w/ frozen soil, 1-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
18
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

19
RUC-2 Analysis, cont.
  • - 3) univariate analyses
  • condensation pressure at all levels
  • ?v 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)

20
Sounding comparison RUC grid vs. raob
Raob sounding RUC2 grid sounding
Close fit to observations in RUC2 analysis
21
Fix to use of sig-level data
Raob RUC after fix RUC before fix 7 April
99 significant-level fix in RUC-2
22
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.
23
RUC2 topography fields
Minimum topo for 2m T/Td
Model topo
24
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

25
Surface Analyses/Forecasts in RUC-2
  • integrated with 3-d 40 km 1 hr cycle
  • dynamic consistency with model forecast gt
    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

26
Divergence - 0900 UTC 20 Jan 98 (blue - conv,
green/yellow - div)
RUC2 Surface Analysis Topographical features
more evident with model background
RUCS 60km surface analysis Little consistency
with nighttime drainage
27
Divergence - RUC2 Surface Analysis - 0600Z 19
April 96 Consistency with topographical features
in model (land/water roughness length variations
in this case)
28
RUC-2 use of surface data
  • All winds, sfc pressure obs used
  • T/Td used if abs (Pstation - Pmodel) lt 70 mb
  • - about 90 west of 105ºW, 99 east of 105ºW
  • Eta48 Eta29 RUC40
  • FGZ 0 18 10
  • TUS 60 13 44
  • SLC 59 68 59
  • MFR 109 48 67
  • OAK 18 15 25
  • SAN 12 5 23
  • DRA 42 29 34
  • GJT 98 105 65
  • RIW 104 27 16
  • GEG 4 11 1
  • GTF 26 4 14
  • UIL 14 9 11
  • SLE 50 15 22
  • BOI 55 21 24

pmodel - pstn
within 5 mb of closest fit
29
Key issues in use of surface data in 3-d data
assimilation
  • Goals
  • 1) best estimate of current conditions
  • 2) best subsequent 3-d model forecast
  • Reduction between station elevation and model
    terrain
  • Use local lapse rate for temperature
  • Moisture? maintain RH (used in RUC), use
    hygrolapse rate?
  • Use consistent and reversible algorithms for
  • going from station to model terrain (analysis)
  • going from model terrain to mini-topo
    (post-processing)
  • Vertical representativeness of surface data
  • RUC potential temperature separation
  • Horizontal representativeness of surface data
  • RUC potential temperature separation in
    horizontal adds to vertical distance

30
Weaknesses in use of surface data in current RUC
3-d analysis
Influence of surface data in analysis limited to
lowest 6 levels (lowest 25-40 mb) How to
determine depth of influence Does an error at
the surface imply the same forecast error
throughout the boundary layer? Sometimes yes,
sometimes no.
31
RUC-2 use of surface data
  • All winds, sfc pressure obs used
  • T/Td used if abs (Pstation - Pmodel) lt 70 mb
  • - about 90 west of 105ºW, 99 east of 105ºW
  • Eta48 Eta29 RUC40
  • FGZ 0 18 10
  • TUS 60 13 44
  • SLC 59 68 59
  • MFR 109 48 67
  • OAK 18 15 25
  • SAN 12 5 23
  • DRA 42 29 34
  • GJT 98 105 65
  • RIW 104 27 16
  • GEG 4 11 1
  • GTF 26 4 14
  • UIL 14 9 11
  • SLE 50 15 22
  • BOI 55 21 24

pmodel - pstn
within 5 mb of closest fit
32
Key issues in use of surface data in 3-d data
assimilation
  • Goals
  • 1) best estimate of current conditions
  • 2) best subsequent 3-d model forecast
  • Reduction between station elevation and model
    terrain
  • Use local lapse rate for temperature
  • Moisture? maintain RH (used in RUC), use
    hygrolapse rate?
  • Use consistent and reversible algorithms for
  • going from station to model terrain (analysis)
  • going from model terrain to mini-topo
    (post-processing)
  • Vertical representativeness of surface data
  • RUC potential temperature separation
  • Horizontal representativeness of surface data
  • RUC potential temperature separation in
    horizontal adds to vertical distance

33
Weaknesses in use of surface data in current RUC
3-d analysis
Influence of surface data in analysis limited to
lowest 6 levels (lowest 25-40 mb) How to
determine depth of influence Does an error at
the surface imply the same forecast error
throughout the boundary layer? Sometimes yes,
sometimes no.
34
RUC surface temperature forecasts - verification
against all METARs in RUC domain
Excellent analysis fit to surface obs (also wind,
Td) 3-h forecast better than 3-h persistence
RMS error
Bias (obs - forecast)
persistence
Validation time
Validation time
35
RUC Digital Filter Initialization
40 Dt forward 40 Dt backward - digital filter
avg of model values Produces much smoother 1-h
fcst
Mean absolute sfc pres tendency each Dt in
successive RUC runs
36
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)

37
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

38
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

39
Processes in RUC2/MM5 microphysics
(Reisner, Rasmusssen, Bruintjes, 1998, QJRMS)
40
RUC2 case study - Quebec/New England ice storm -
9 Jan 1998
500 mb height/vorticity - 9h RUC2 fcst valid
2100 UTC
41
RUC2 9h fcst - Surface temp (image), MSLP (beige
isobars)
42
N-S cross-section - temperature (isopleths, int
2 deg C, solid for gt 0) RH (image), 9h RUC2
forecast
YUL
43
Montreal ice storm - 9h RUC2 forecast valid 2100
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
44
40 km RUC versus 32 km Eta
June-July 1999
45
40 km RUC versus 32 km Eta
June-July 1999
46
RUC vs. Eta 12-h fcsts 250mb RMS vector error

12 11 10 9 8 7 6 5
From 80km grids for both models RUC uses 24h Eta
for lateral boundary conditions
Comparable skill, potential for ensembles
47
RUC 1, 3, 6, 12h forecasts valid at same time
(against 0000 and 1200 UTC rawinsonde data)
Better wind and temperature forecasts with use
of more recent asynoptic data
48
RUC/MAPS Land-surface Process Parameterization
(Smirnova et al. 1997, MWR 1999, JGR) Ongoing
cycle of soil moisture, soil temp,
snow cover/depth/temp)
2-layer snow model
49
Previous MAPS vegetation New
vegetation BATS classes
Addition of high-resolution EOS vegetation-type
data to backup RUC - September 1999 NCEP
RUC summer 2000
50
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 field 5 Jan 1999 2200 UTC
1 2 3
4 5
51
RUC2 Output Files
  • 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 qe)
  • (Added to NCEP RUC on 27 Jan 2000)
  • Likely to start within next few months
  • 212 grids (236 subset of 212 - 151x113 RUC
    domain) will be available

52
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
53
27 Jan 2000 post-processing change
  • 8 new variables in post-processing
  • visibility
  • ceiling
  • cloud top (stable)
  • sfc wind gust
  • PBL height
  • convective cloud top
  • equilibrium level
  • pressure of max qe
  • fix to 3h sfc pressure change

54
RUC visibility
0200 UTC 7 Feb 2000 METAR plot 0300 UTC 7
Feb 2000
55
RUC visibility and ceiling vs. METAR IFR/MVFR
1700 UTC 4 Dec 1999
56
RUC sfc wind gust speed
0300 UTC 7 Feb 2000
57
RUC precip type study SPC Greg Carbin
58
RUC cloud analysis design
59
RUC/MAPS 1-h cloud-top fcsts with and
without GOES cloud-top assimilation
(clearing and building) (1200 UTC 14 May
1999)
1-h fcst w/o GOES cloud assim
1-h fcst w/ hourly GOES cloud assim
NESDIS cloud-top (verification)
60
Correspondence between MAPS cloud fcsts and sat
images
Visible satellite image at 1745z 28 Oct 99
1-h MAPS cloud-top fcst with previous GOES
assimilation -- valid 18z 28 Oct 99
- improved with GOES cloud-top assimilation
61
No GOES
w/ GOES
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.
62
Cloud-top verification with and without initial
cloud analysis
Parallel - with cloud analysis
0.7
Control - no cloud analysis
0.5
0.3
Julian date
September 1999 - fall
- correlation coefficient between RUC
forecasts and NESDIS cloud-top pressures
Significant improvement in RUC cloud-top
forecasts with cloud analysis, esp. for 1-h
forecasts, but smaller but consistent
improvement even in 12-h forecasts
63
Visible satellite image at 1745z 28 Oct 99
NESDIS Cloud-top product (sounder-based) 1800z
28 Oct 99
64
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 and national radar data both mapped
to RUC 40km grid
65
Precipitation fixes
  • Current Operational RUC
  • bug in link between convective parameterization
    and PBL tendency
  • microphysics called every
  • 10 min
  • Backup RUC
  • bug fixed, microphysics called every 4 min
  • note difference in convective precip over warm
    ocean areas,
  • Intensity over sw Missouri

66
RUC 3dVAR Development
  • Uses native q-s coordinate
  • In grid point space but part at coarser
    horizontal resolution
  • Control variables - z, y, c (explicit
    divergence), q, ln q
  • Uses Purser recursive filters
  • Constraints - weak geostrophy
  • Includes analog QC (following Dharssi et al.,
    QJRMS)
  • Smoother analysis increments
  • Use of all observations, no superobservations
  • No synthetic obs use only raw data
  • Much better structure for using radiances, wind
    speed..
  • Incorporate adjustment to hybrid coordinate
    within analysis
  • Multi-grid scheme, inner/outer loop

67
3-d VAR vs. Optimal interpolation - 40-day
parallel cycle test (60-km 3-h cycle) (thin -
OI, thick - 3dVAR) 3-dVAR giving closer fit to
obs in winds/heights for analysis and 12h
forecasts than OI
3dVAR
OI
3dVAR
OI
3dVAR
3dVAR
OI
OI
68
Other improvements coming in 20km RUC (already in
backup RUC)
  • Grell version of RUC model
  • Fix to bug in PBL/convective scheme link
  • Improved consistency in ordering of physics
  • Restructured code more modularized
  • Revisions to Grell convective scheme in RUC
  • Improvements esp. in convective precip
  • Fixes to boundary condition problems
  • Shorter time step for microphysics
  • Improved stable precipitation QPF
  • Revised version of MM5/RUC microphysics
  • Improved precip type, stable precip QPF
  • Fix timing of shortwave radiation 30-60 min lag

69
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 Call MM5 microphysics more often (currently
    10 min) backup RUC calling every 3-4 min much
    improved
  • Too much precip over warm oceans, too little near
    SE coast in cold season
  • Fix of bug link between boundary-layer
    tendencies and RUC convective parameterization
  • Fix now running in backup RUC look at web page
    prods
  • Daytime convective precip in summer too
    widespread
  • Same as above
  • Fix now running in backup RUC

70
RUC-2 Weaknesses, cont.
  • Convective precip forecasts miss many small
    areas, underforecast peak amounts.
  • Much better performance expected in summer 2000
    due to fixes
  • 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
  • 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

71
RUC-2 Strengths
  • Surface fields, especially surface winds
  • RUC model/analysis has level at 10 m,
  • very little smoothing
  • Topographically induced circulations
  • sea/lake breezes (scale too large but theyre
    there)
  • mtn/valley circulations
  • differential friction effects
  • e.g. Catalina eddy

72
RUC-2 Strengths, cont.
  • Precipitation fields
  • more detailed in summer than Eta (lower FAR but
    lower POD), major improvements in backup RUC ?
    NCEP RUC
  • 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

73
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

74
RUC-2 use of surface data
  • All winds, sfc pressure obs used
  • T/Td used if abs (Pstation - Pmodel) lt 70 mb
  • - about 90 west of 105ºW, 99 east of 105ºW
  • Eta48 Eta29 RUC40
  • FGZ 0 18 10
  • TUS 60 13 44
  • SLC 59 68 59
  • MFR 109 48 67
  • OAK 18 15 25
  • SAN 12 5 23
  • DRA 42 29 34
  • GJT 98 105 65
  • RIW 104 27 16
  • GEG 4 11 1
  • GTF 26 4 14
  • UIL 14 9 11
  • SLE 50 15 22
  • BOI 55 21 24

pmodel - pstn
within 5 mb of closest fit
75
Key issues in use of surface data in 3-d data
assimilation
  • Goals
  • 1) best estimate of current conditions
  • 2) best subsequent 3-d model forecast
  • Reduction between station elevation and model
    terrain
  • Use local lapse rate for temperature
  • Moisture? maintain RH (used in RUC), use
    hygrolapse rate?
  • Use consistent and reversible algorithms for
  • going from station to model terrain (analysis)
  • going from model terrain to mini-topo
    (post-processing)
  • Vertical representativeness of surface data
  • RUC potential temperature separation
  • Horizontal representativeness of surface data
  • RUC potential temperature separation in
    horizontal adds to vertical distance

76
Weaknesses in use of surface data in current RUC
3-d analysis
Influence of surface data in analysis limited to
lowest 6 levels (lowest 25-40 mb) How to
determine depth of influence Does an error at
the surface imply the same forecast error
throughout the boundary layer? Sometimes yes,
sometimes no.
77
RUC
MesoEta
Theta
Mtn wave comparison - MesoEta vs. RUC2
78
MesoEta
RUC
U - component Mtn wave comparison - MesoEta vs.
RUC
79
W - vertical velocity Mtn wave comparison -
MesoEta vs. RUC
80
20km RUC/MAPS topography - 2000

Subset of full domain
81
20km vs. 40km topography
Subset of full domain
20km RUC/MAPS
40km RUC/MAPS
82
13km RUC - 12h forecast
- start 0000 UTC 27 October 1997
Precipitation Surface winds
83
13km RUC - 6h forecast
10
20
25
20
valid 06Z 27 Oct 97 6-h precipitation (cm),
wind speed (m/s) in cross-section
84
The Future of the RUC
  • Transfer of current 40km RUC2 to IBM SP - 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

85
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
  • Key areas of upcoming improvement
  • Precipitation stable and convective
  • Cloud analysis cloud fields
  • Surface/orographic effects resolution,
    land-use
  • Wind/temp/RH fcsts

86
The Future of the RUC, cont.
  • Non-hydrostatic q-sz model under development
  • Generalized vertical coordinate
  • Nudging of coordinate surfaces toward grid
    generator
  • can be set as smoothed quasi-isentropic hybrid
    coordinate
  • treats sub20km variations (convective clouds,
    breaking mountain waves) w/ quasi-horizontal
    coordinates
  • treats gt20km variations w/q-s 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?

87
Quasi-isentropic option for WRF non-hydrostatic
model Breaking mountain wave simulation - 2 km
horizontal resolution Sigma-z version Quasi-isent
ropic version
Thick - q Thin - coordinate surfaces
88
Rapid Update Cycle Present and Next Version
1999 Operations 2000-01 Operations Resolution
40 km, 40 q/s levels 20?15 km, 40 ? 50-60 q/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), 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,
2-layer snow, improved hi-res land use,
1997, 1999) w/ frozen soil, 1-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
89
Feedback
  • Send feedback/questions on RUC performance to the
    RUC discussion forum.
  • Invite us to workshops.
  • http//maps.fsl.noaa.gov/forum/eval
  • RUC/MAPS Internet forum subscribe for automatic
    emails
  • 303-497-6387
  • benjamin_at_fsl.noaa.gov
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