glfe realtime tamdar impact experiments with the 20km ruc

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Stan Benjamin,Tracy Lorraine Smith, Bill
Moninger, Brian JamisonNOAA Forecast Systems
LaboratoryBoulder, CO
GLFE Real-time TAMDAR Impact Experiments with the
20km RUC
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Outline of talk Part 1 General description of
RUC 1h cycle - Data assimilated - Spatial
effects of assimilated data Recent enhancements
to RUC assimilation Previous results from RUC
data impact experiments Design of RUC parallel
experiments Dev / Dev2 Examples of Dev/Dev2
difference fields (Brian Jamison) Part 2 Actual
statistical results
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Purpose for Rapid Update Cycle (RUC) model run
operationally at NCEP

• Provide high-frequency mesoscale analyses,
  short-range model forecasts
• Use all available observations
• Users
• aviation/transportation
• severe weather forecasting
• general public forecasting
• Focus on 1-12 hour forecast range
• Accuracy of surface fields very important

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Rapid Update Cycle Model Features
Vert Coord Hybrid sigma-isentropic Stable
clouds, NCAR mixed-phase (cloud water,
precipitation rain water, snow, graupel, ice,
ice particle number. concen. Sub-grid Grell
-Devenyi ensemble scheme precipitation (144
members, mean to model) Land-surface RUC LSM -
6-level soil/veg model, 2-layer snow model
(Smirnova)
Current operational RUC 20-km Planned upgrade
2005 13-km
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RUC Assimilation System
Updates 1-h cycle Analysis 3DVAR on q/s
surfaces (y/c/Zunb, q, lnQ) Details Balanced
height (NMC method) Length-scales modified
from OI Sfc Obs/ Use surface obs through
PBL PBL Structure Lapse-rate checks Noise Adiaba
tic digital filter initialization
Clouds/ Cloud analysis (GOES cloudtop
pres, moisture radar reflectivity, METAR
clouds) Cycling of cloud, hydrometeor,
land-surface fields
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RUC Hourly Assimilation Cycle
1-hr fcst
1-hr fcst
1-hr fcst
1-hr fcst
1-hr fcst
1-hr fcst
Background Fields
Analysis Fields
Time (UTC)
11 12 13 14
15 16
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RUC Hourly Assimilation Cycle
3-hr fcst
3-hr fcst
3-hr fcst
3-hr fcst
Background Fields
Analysis Fields
EC
Time (UTC)
11 12 13 14
15 16
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Cloud anx variables
Observations used in RUC Data Type
Number Freq. ------------------------------
-------------------- Rawinsonde 80
/12h NOAA profilers 30 / 1h VAD
winds 110-130 / 1h Aircraft (V,temp)
1400-4500 / 1h Surface/METAR
1500-1700 / 1h Buoy/ship 100-150
/ 1h GOES precip water 1500-3000 / 1h GOES
cloud winds 1000-2500 / 1h GOES cloud-top
pres 10km res / 1h SSM/I precip water
1000-4000 / 6h ----------------------------------
---------------- GPS precip water 300 /
1h Mesonet 5000 / 1h PBL prof/RASS
20 / 1h Radar refl / lightning 4 km
res ----------------------------------------------
----
NCEP operational
FSL experimental
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• Application of Digital Filter Initialization in
  RUC
• 45 min forward, 45 min backward no physics
• Average over DFI period

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• RUC Analysis
• 3-d effect of observations dependent on
  statistically determined forecast error
  covariance
• vertical dependent on ?
• horizontal smaller near surface, larger aloft,

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• RUC20
• Wind forecast
• Accuracy
• Sept-Dec
• 2002

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9
1
3
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Analysis truth
6 8 10 12
(kts)
Verification against rawinsonde data over RUC
domain RMS vector difference (forecast vs. obs)
RUC is able to use recent obs to improve forecast
skill down to 1-h projection for winds
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Results from fall 2002 better moisture results
in RUC13 Potential for more improvement from
TAMDAR V, T, RH
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Use of surface obs information throughout
boundary layer in the RUC analysis

• Problem
• Information from surface
• observation not used through
• depth of PBL by RUC analysis
• Surface observation not
• retained in model forecast

Original analysis
Dewpoint
Temperature

Surface Observation
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Use of surface obs information throughout
boundary layer in the RUC analysis

• Problem
• Information from surface
• observation not used through
• depth of PBL by RUC analysis
• Surface observation not
• retained in model forecast

• Solution
• Use METAR observation throughout PBL depth
• (from background field)
• Better model retention
• of surface observations

Original analysis
Analysis with use of PBL depth
Dewpoint
Temperature

Surface Observation
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CAPE impact from two RUC enhancements
0000 UTC 21 Apr 2004
3h fcst WITH enhancements
3h fcst OPERATIONAL

• RUC enhancements
• Use of METAR obs through
• boundary-layer depth (Sept 04)
• Assimilation of GPS precipitable
• water observations (May 2005)

Severe reports
NWS SPC Norman, OK
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RUC Cloud Analysis

• Use GOES CTP, radar reflectivity, lightning,
• METAR (clouds,wx,vis) to modify moisture fields
• Construct 3-d logical arrays (YES/NO/UNKOWN)
• for clouds and precipitation from all info
• Clear/build (change qc, qi, qv) with logical
  arrays
• Safeguards for pressure-level assignment
  problems
• (marine stratus, convective clouds)
• Use nationwide mosaic radar data to modify water
• vapor, hydrometeor fields
• Lightning data used as a proxy for radar
  reflectivity
• Feedback to cumulus parameterization scheme

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GOES cloud top pressure
Radar/lightning data
100 200 300 400 500 600 700 800 900 999
PRES
RH
Qv
Qc
Cloudwater, water vapor and relative humidity
before ( ) and after (----) GOES Cloud- top
pressure adjustment
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3h 20km fcst WITH GOES cloud assim
NESDIS GOES Verification cloud-top prs
1200 UTC 9 Dec 2001
Cloud-top pressure (mb)
3h 40km fcst NO GOES cloud assim
Sample 20-km RUC forecast impact from GOES
cloud-top pres. assimilation
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Assimilation of METAR cloud/wx/vis Better
analysis, prediction of ceiling and visibility
- Nearest station up to 100 km distance - Maps
info to 3-d cloud, precip. Y/N/U arrays - Change
qc, qi, qv as follows Build for BKN / OVC /
Vertical Visibility - 40 mb thick layer (2
model levels) - 150 mb thick for precip GOES
clouds - Can build multiple broken
layers Clear - Up to cloud base (if needed)
- to 12 kft for CLR report
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analysis with METAR cloud/ visibility obs
Cloud water mixing ratio
Sample modification of cloud water (qc) from
METAR cloud/weather/ Visibility obs
1700 UTC 27 Jan 2004
RH, ?
Cloud water mixing ratio
Background 1h fcst
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Sample ceiling analysis impact
Analysis WITH cld/wx/ vis obs
Ceiling from RUC hydrometeors
Observations
1800 UTC 17 Nov 2003
Aviation Flight Rules
Analysis NO cld/wx/ vis obs
cloud ceiling height (meters)
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Sample ceiling forecast impact
3h fcst WITH cld/wx/ vis obs
Ceiling from RUC hydrometeors
Observations
2100 UTC 17 Nov 2003
Aviation Flight Rules
3h fcst NO cld/wx/ vis obs
cloud ceiling height (meters)
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Planned upgrades to RUC model

• 2005 ? 13-km operational at NCEP
• Assimilation of new observations
• - METAR cloud/vis/current weather
• - Mesonet
• - GPS precipitable water
• - Boundary layer profilers, RASS temperatures
• - Radar data (when available at NCEP)
• Model improvements new versions of
• - Mixed-phase cloud microphysics (NCAR-FSL)
• - Grell-Devenyi convective parameterization
• ? Planned operational implementation
• of WRF-based rapid-refresh

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3-d RUC weather data updated hourly
20km x 50 vertical levels x 14 variables
Turbulence
Ceiling/visibility
Convection - 2-12h forecast
Terminal / surface
Icing
Better weather products require improved
high-frequency high-resolution models with
high-refresh data to feed them
Winds
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Wind forecast errors - defined as
rawinsonde vs. forecast difference
Anx Fit - truth
Cntl using all obs Exp deny profiler obs
Difference in errors between Cntl and
Exp experiments w/ RUC - 4-17 Feb 2001
Positive difference means CNTL experiment with
profiler data had lower error than the EXP-P
no-profiler experiment
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Wind forecast impact US National domain
3h
6h
6h
3 h

• Impact generally greatest for shorter forecast
  durations.
• Decreases with projection except raobs
• Raob impact largest at 12h raob frequency is
  12h.
• Aircraft - largest overall impact at 3h,
  profiler next (much smaller)
• Modest VAD and METAR impact aloft (METARs
  improve low-level height field, which helps z?p
  mapping needed for VADs and profilers)

12h
12 h
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• Real-time TAMDAR impact experiment design
• Parallel 20km RUC 1-h cycles
• Dev cycle all obs data but no TAMDAR
• Dev2 cycle dev TAMDAR data
• Lateral boundary conditions same for Dev and
  Dev2
• Control design
• Initialize Dev and Dev2 runs at exact same time
• Reset dev and dev-2 background field at 1000z
  every 48 h (even Julian dates)
• Ensure against any computer logistics
  differences
• Evolution of dev vs. dev2 is different
• Example buddy check QC in each cycle may
  occasionally differ for non-TAMDAR data
• Slight difference in gravity waves
• Can propagate difference throughout domain
• Shows up in sfc temps, convection, esp. 925, 850
  mb

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0900z ---------? 1200z

• Sunday 10 April 2005
• Reset of dev-dev2 difference at 1000z
• by copying Dev RUC 1-h forecast from 0900z as
  background for Dev2 analysis at 1000z
• Reset is effective (although

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Dev-Dev2 difference 12h fcst Init 1200z 10
April 2005 500 mb
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Dev-Dev2 difference 12h fcst Init 1800z 10
April 2005 700 mb
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• Real-time TAMDAR impact experiment design
• Parallel 20km RUC 1-h cycles
• Dev cycle all obs data but no TAMDAR
• Dev2 cycle dev TAMDAR data
• Lateral boundary conditions same for Dev and
  Dev2
• Control design
• Initialize Dev and Dev2 runs at exact same time
• Reset dev and dev-2 background field at 1000z
  every 48 h (even Julian dates)
• Ensure against any computer logistics
  differences
• Evolution of dev vs. dev2 is different
• Example buddy check QC in each cycle may
  occasionally differ for non-TAMDAR data
• Slight difference in gravity waves
• Can propagate difference throughout domain
• Shows up in sfc temps, convection, esp. 925, 850
  mb

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Part 2 Statistical results
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Verification regions for FSL-RUC TAMDAR impact
Large region (eastern half of US) -- 38 RAOB
sites Small region (Great Lakes) includes 14 RAOBs
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Wind forecast errors - defined as
rawinsonde vs. forecast difference
Anx Fit - truth
Cntl using all obs Exp deny profiler obs
Difference in errors between Cntl and
Exp experiments w/ RUC - 4-17 Feb 2001
Positive difference means CNTL experiment with
profiler data had lower error than the EXP-P
no-profiler experiment
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Temperature shows notable improvement for 850 mb,
3-h forecast in large (E.US) region
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Even clearer improvement in the small (Gt Lakes)
region
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Temperature bias small improvement for 850 mb,
3-h forecast
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Much improved temperature bias in small region
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Temperature some improvement for 700 mb, 3-h
forecast
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Winds not much difference
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Relative Humidity not much difference
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Results wind Great Lakes region only 1 March
12 April 2005
Only 00z times -------------- V
m/s average diff by level pres 0h-an 12h
3h 6h 9h 1h 850
0.04 0.02 -0.07 -0.08 0.02 0.04 0.07
-0.01 0.09 700 -0.01 0.01 0.08 0.03
-0.05 -0.04 -0.02 0.03 0.06 500 -0.07
0.00 0.04 -0.04 -0.08 -0.04 -0.06 0.04
-0.08 400 -0.03 0.07 0.05 -0.06 -0.03
-0.02 0.03 -0.06 -0.04 300 0.00 0.06
0.04 0.09 -0.01 0.00 0.05 -0.02
0.00 250 0.00 -0.07 0.04 0.02 -0.05
0.03 0.02 0.00 0.05 200 0.01 0.07
-0.01 -0.04 -0.07 0.03 0.02 -0.01
0.04 150 0.02 0.01 0.07 -0.01 0.01
0.05 -0.01 -0.02 0.04
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Results temperature Gt Lakes region only 1
March 12 April 2005
Only 00z times -------------- T deg
C average diff by level pres 0h-anx 12h 3h
6h 9h 1h 850 0.13 -0.02 0.23
0.11 -0.02 0.36 700 0.05 0.00 0.06 0.04
0.01 0.03 500 0.01 -0.01 0.04 0.01
-0.01 0.05 400 -0.01 0.00 -0.02 0.00
0.00 0.01 300 -0.02 0.00 -0.03 -0.02 -0.01
-0.01 250 -0.05 -0.01 -0.03 -0.02 0.00
-0.01 200 -0.03 0.01 -0.02 -0.04 -0.01
-0.03 150 0.03 0.03 -0.01 -0.02 0.04
0.01
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• FSL-RUC TAMDAR impact experiment results
• (as of 12 April 2005)
• Impact experiments must be conducted such as to
  show value added to other existing observations
• RUC well-suited for this
• Real-time parallel cycles at FSL (Dev/Dev2) have
  provided well-controlled experiments and results
• Accelerated evaluation process
• Results are very preliminary and during TAMDAR
  shakedown phase
• Temperature impact strongest
• 20 reduction of 3h forecast error
• RH impact less but positive
• No impact for wind
• Diurnal variations more 3h impact at 00z than
  12z
• Results will improve with
• Improved TAMDAR data
• Future use of reject lists (updated weekly?)