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The Variational Version of the Local Analysis and Prediction System (LAPS): Hot-start Data Assimilation of Convective Events. Steve Albers, Yuanfu Xie, Hongli Jiang , Dan Birkenheuer, Isidora Jankov, and Zoltan Toth ESRL/GSD WRF Workshop June 26 th 2013. Updated 6/2 5 /2013 1 81 0UTC. - PowerPoint PPT Presentation
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The Variational Version of the Local Analysis and Prediction System
(LAPS): Hot-start Data Assimilation of Convective Events
Steve Albers, Yuanfu Xie, Hongli Jiang, Dan Birkenheuer, Isidora Jankov, and Zoltan Toth
ESRL/GSDWRF Workshop June 26th 2013
Updated 6/25/2013 1810UTC
Presentation Outline
LAPS Overview
Windsor Tornado
Hazardous Weather TestBed (HWT)
Future Plans
LAPS System Overview
Data Ingest
Intermediatedata files
GSI
FORECAST MODEL (e.g. WRF)
Verification
Analysis Scheme
Downscaling can work as a stand alone module
from background → GSI or other
applications such as Fire wx.
Downscaling is also an integral part of variational LAPS
(aka. STMAS).
Data Background (or cycled forecast)Observations
Standalone downscaling
module
Traditional LAPS
Variational LAPS (with downscaling)
Model prep
LAPS MotivationHigh Resolution (500m – 20km), rapid update (10-60min)
Highly portable system Collaboration with user community - about 150 world wide
Federal Gov’t – NWS, RSA, PADS, FAA, DHS State Gov’t – California Dept of Water Resoures International – Finnish Met. Inst., China Heavy Rain Inst. Local to Global analysis – used by SOS
Wide variety of data sources:
OAR/ESRL/GSD/Forecast Applications Branch *
Transition from Traditional to Fully Variational LAPS
state vars, wind (u,v) clouds / precip
balance and constraintsin multi-scale variational
analysis
Windanalysis
Temp/Ht analysis
Humidity analysis
Cloud analysis
balance
Traditional LAPS analysis: Wind, Temp, Humidity, Cloud, Balance
Ultimately
Temporary hybrid system: Traditional LAPS cloud analysis and
balance
NumericalForecast
model
Large Scale Model First Guess
Cycling Option
Var.LAPS
Cloud Analysis Flow Chart
Cloud Fraction 3-D Isosurface
*
(From radars and model first guess)
Cloud Analysis Independent ValidationAll-sky Imager• Compare LAPS simulated all-sky analyses (or forecasts) to actual all-sky imagery
• Validates quality of analyses (or forecasts) of clouds / visibility obstructions
Courtesy: Longmont
Astronomical Society
All-Sky Camera
Sun Glare
Cloud Analysis Independent Validation
All-sky Imager• This example has more clouds with high opacity
• Validation leads to improvements (e.g. parallax correction, thin cirrus)
Courtesy: Longmont Astronomical Society
Sun Glare
Windsor, CO 2008 Tornado Simulations
Model Initial Conditions Boundary Condition Resolution
wrf-wsm6RUCp 3h fcst +
Variational LAPSRUCp+WRF
da_update_bc 1.67km (Xie)
wrf-tomRUCp 3h fcst +
Variational LAPS analysis
RUCp + WRF da_update_bc 3km (Jiang)
Windsor - 700 mb reflectivity initial=2008052217, 1h fcst
Mosaic radar vs. WRF forecast (1.67 km res)
Analyzed Radar / 10 min Forecast
T T
Hazardous Weather Testbed (HWT) Experimental Warning Program (EWP)
2013 Experiment Domains & FieldsForecast: regional domain at 1 km and 3 km resolutions, hourly re-initialization with
15 min model output.• Composite Reflectivity
• CAPE
• CIN
• Updraft Helicity
• Lifted index
• Satellite simulated IR Brightness Temperature
• Fractional Cloud Cover
• Cloud Ceiling
Surface analysis: conus domain at 2.5 km resolution available hourly• Surface Temperature
• Dew Point Temperature
• U,V wind component
• PMSL
• surface pressure
Observed & Forecast IR Satellite Brightness Temp HWT 3km Domain 25 Jun 2013 0400 - 0600Z
• Simulated VIS also available (derived from cloud amount)• Forecasters are naturally familiar with satellite images• Used for objective cloud forecast verification
OBS Forecast
HWT Forecasters’ Input (real time EWP Blog)
LAPS again. Higher CAPE, bow echo. Lower CAPE, bye bye bow echo.Posted on May 14, 2013“In my opinion, the LAPS surface-based CAPE product was one of the stars of the day. Consistently, storms lived and died based on entering and exiting the tongue of higher CAPE values which extended north and northeast from the Big Bend area for most of the day. This first image shows the LAPS surface-based CAPE at 00Z, and the radar at the same time. Shouldn’t be hard to pick out the storm of interest. Note that the storm is still in the tongue of 1000+ J/kg of CAPE as noted on LAPS.
One hour later, the storm is exiting and entering a less favorable instability regime. And predictably, it starts to weaken
Any questions? LAPS nailed it.”CL
Moore Tornado Related Blog Entries LAPS Observations and Determining Future Storm Development…Posted on May 20, 2013 “Just a quick post about observations of the LAPS theta-e field this afternoon. It was interesting to see the near stationary aspect of the theta-e boundary in assoc/w the dryline to our south across portions of north Texas this afternoon. This suggests that continued development is possible late this afternoon especially across northern Texas, where the gradients have been sustained and have even increased lately. However, notice that the gradients have decreased generally across much of Oklahoma where convection and related effects (rain cooled air, cloud shield) have helped to stabilize the environment. The 15-minute temporal resolution of the product can be very useful for diagnosing locations of continued convection especially in rapidly developing convective situations.”
2115UTC 2130UTC
2145UTC 2200UTC
LAPS analysis. Shaded values are sfc theta-e (K), while wind vectors are in blue.
LAPS niche: Good handle on existing convection and lead time on CI
HWT 1km V-LAPS0-3 h Composite Reflectivity Verification
Higher ETS (best at short lead time)Compare WRF initialization schemes, work with DTC?
Var. LAPS Initialization
Moore Tornado 1hr LAPS Forecast
Simulated IR Satellite Forecast
*
Simulated IR Satellite LAPS / WRF 6-Hr Forecast Verification
Forecast high clouds sometimes look too thick
Future Plans - Cloud Analysis
Develop and validate forward models and their adjoints for all data sources being used to more fully implement a variational approach
Utilize improved constraints relating various control and derived variables
Combine ensemble background error covariances into multiscale variational analysis, i.e., different scale error covariances applied at different multigrid levels of the variational LAPS analysis
OAR/ESRL/GSD/Forecast Applications Branch *
Cloud Forecast Plans
Improve Hot-Start Elementso Hydrometeors, Temperature, Water Vapor, Vert-Vel
Examine various WRF radiation options and their consistency with microphysics
Consider water vapor given small-scale / partial clouds in a grid-box
Combine with analysis for 4DVAR
OAR/ESRL/GSD/Forecast Applications Branch *
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