Future NCEP Guidance Support for Surface Transportation
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Transcript of Future NCEP Guidance Support for Surface Transportation
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Future NCEP Guidance Support for Surface Transportation
Stephen LordDirector, NCEP Environmental
Modeling Center26 July 2007
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Overview• Weather for Roads, Air transportation, etc.
– National picture• New ensemble products
– Local picture• Downscaling
– Real-time Mesoscale Analysis (RTMA)– Land Information System (LIS)– Dynamical – Statistical approach
• Marine applications– Waves– Water levels
• Data availability• What’s needed to move ahead
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New Ensemble Products fromNCEP Storm Prediction Center
• NCEP Short-Range Ensemble Forecast (SREF) System• National coverage ~ 30 km grid• Probabilistic guidance with extremes
SREF Maximum (any member) 3h Accumulated Snowfall
SREF Pr[Ptype = ZR] and Mean P03I (contours)
SREF 6h Calibrated Probability of Snow/Ice Accum
Accumulation based on MADIS road surface condition
D. BrightNCEP/SPC
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SREF Likely PTYPE and Mean P03I (contours)
Rain
SnowZR
IP
24 h FcstPrecip Type, Amount
32 F Isotherm
D. BrightNCEP/SPC
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Downscaling• Future computing requirements
– National scale ~20 years to reach sufficient resolution
• Dynamical-statistical approach– Real time Mesoscale Analysis (RTMA)– Land Information System (LIS)– Bias correction and statistical processing
• Components under development
Forecast System
Current Horizontal Resolution
Current Vertical Resolution
Future Horizontal Resolution
Future Vertical Resolution
Other factors Total Compute Factor
Years to Achieve at current constant funding
NAM 12 60 2 100 2x physics 720 19
SREF 37 48 5 100 844 20
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Real-Time Mesoscale Analysis (RTMA)
RTMA Temperature Analysis (° F) (17Z 6/14/07)
RTMA 1-hour Precipitation Analysis (inches) (01z 6/14/07)
RTMA Temperature Analysis Uncertainty (° F) (17Z 6/14/07)
• 5 km National (NGDG) grid (eventually 2.5 km)• Hourly analysis
– Focus on “drawing to obs” (mesonet)– Temperature, precipitation, surface wind, dew point– Anisotropic (e.g. land-water contrast)
• Analysis uncertainty• To include cloud cover• Will cover CONUS, Alaska, Hawaii, Puerto Rico, Guam
M. PondecaJ. Purser
G. DiMegoNOAA/GSD - RUC
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Land Information System (NASA/NOAA)• Land states forced by
– Observed precipitation– Model solar, long wave radiation,
cloudiness
• Noah Land Surface Model (LSM) defines skin temperature, soil moisture, etc.
• Can be run at 1 km resolution (below)
00 UTC7 PM
03 UTC10 PM
06 UTC1 AM
09 UTC4 AM
12 UTC7 AM
15 UTC10 AM
18 UTC1 PM
21 UTC4 PM
S. Kumar Jim Geiger
C. Peters-LidardJ. Meng
K. Mitchell
Surface (skin) Temperature 50 km area Washington DC NASA LSM GFS forcing00 UTC 1 July – 21 UTC 1 July
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Dynamical Statistical Approach
• Bias correction of forecast fields with respect to model analysis (e.g. NAM)
• “Downscaling Transformation” (DT)– Produces time-dependent differences between coarse forecast
model (e.g. 12 km NAM) and RTMA (5 km)
• Downscaled (local) fcst =NAM fcst + Bias correction + DT
– On local grid
• Probabilistic products– Created from ensemble systems (SREF, GENS) through
Bayesian Model Averaging (BMA) approach– Applications for
• Road transportation• Air transportation management (NEXTGEN)• Severe weather forecasting
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Marine ApplicationsMulti-Grid Wave Modeling
Multi-grid wave model tentative resolutions in minutes for the parallel
implementation in FY2007-Q4.
Deep ocean model resolutionHigher coastal
model resolution
Highest model resolution in areas of special
interest
Hurricane nests moving with storm(s) like GFDL
and HWRFWave ensemble system application for ship routing
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NCEP Real-Time Ocean Forecast System (RTOFS)Operational December 2005, upgraded June 2007
Chesapeake Bay
• RTOFS provides– Routine estimation of the ocean
state [T, S, U, V, W, SSH]• Daily 1 week forecast
– 5 km coastal resolution– Initial and boundary conditions
for local model applications• Applications
– Downscaling support for water levels for shipping
– Water quality– Ecosystem and biogeochemical
prediction– Improved hurricane forecasts– Improved estimation of the
atmosphere state for global and regional forecasts
• Collaboration with NOAA/NOS
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Product Availability
• Three levels of information– Routinely delivered
1. Pointwise, single-valued, downscaled MLF* from all available guidance on NDGD grid
2. Description of forecast uncertainty through probability density function (mode & 10/90 %ile)
• Accompanying post-processed fields– Meteorologically consistent– Closest to MLF*
– “On-demand” (via publicly accessible server)3. Individual ensemble member forecasts available• Prototype: NOMADS
* MLF – Most Likely Forecast
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What’s Needed?
• Written requirements for surface transportation to NWS
• Operational (and research) computing resources
• Acceleration of current dynamical-statistical efforts
• Outreach and coordination with local users
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Concurrent execution of global and regional forecast models (Phase 2)
Model Region 1
Model Region 2
Global/Regional Model DomainAnalysis
Local Solution
• Real time boundary and initial conditions available hourly
– “On-demand” downscaling to local applications• Similar to current hurricane runs but run either
– Centrally at OR– Locally (B.C, I. C. retrieved from on-line data)
• No boundary or initial conditions older than 1 hour – Flexibility for “over capacity” runs (e.g. Fire Wx, Hurricane)
• Using climate fraction must be planned• No impact on remainder of services
• For NEXTGEN: A consistent solution from global to local with a single forecast system and ensembles providing estimate of uncertainty