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 6/25/2013 1810UTC
LAPS System Overview Data Ingest Intermediate data 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
Slide 4
LAPS Motivation High Resolution (500m 20km), rapid update
(10-60min) Highly portable system Collaboration with user community
- about 150 world wide Federal Govt NWS, RSA, PADS, FAA, DHS State
Govt 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*
Slide 5
Transition from Traditional to Fully Variational LAPS state
vars, wind (u,v) clouds / precip balance and constraints in
multi-scale variational analysis Wind analysis 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 Numerical
Forecast model Large Scale Model First Guess Cycling Option Var.
LAPS
Slide 6
Cloud Analysis Flow Chart Cloud Fraction 3-D Isosurface * (From
radars and model first guess)
Slide 7
Cloud Analysis Independent Validation All-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
Slide 8
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 - 700 mb reflectivity initial=2008052217, 1h fcst
Mosaic radar vs. WRF forecast (1.67 km res) Analyzed Radar / 10 min
Forecast TT
Slide 11
Hazardous Weather Testbed (HWT) Experimental Warning Program
(EWP) 2013 Experiment Domains & Fields Forecast: 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
Slide 12
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
OBSForecast
Slide 13
HWT Forecasters Input (real time EWP Blog) LAPS again. Higher
CAPE, bow echo. Lower CAPE, bye bye bow echo. Posted on May 14,
2013May 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. Shouldnt 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
Slide 14
Moore Tornado Related Blog Entries LAPS Observations and
Determining Future Storm Development Posted on May 20, 2013May 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
Slide 15
HWT 1km V-LAPS 0-3 h Composite Reflectivity Verification Higher
ETS (best at short lead time) Compare WRF initialization schemes,
work with DTC? Var. LAPS Initialization
Slide 16
Moore Tornado 1hr LAPS Forecast
Slide 17
Simulated IR Satellite Forecast * Simulated IR Satellite LAPS /
WRF 6-Hr Forecast Verification Forecast high clouds sometimes look
too thick
Slide 18
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 *
Slide 19
Cloud Forecast Plans Improve Hot-Start Elements o 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*
Slide 20
ExREF Experimental Regional Ensemble Forecasting System
Experimental GSD: Realtime runs & develop HMT: Extreme pcp
guidance DTC: Evaluation WPC: Flash Flood Experiment EMC: test
methods for SREF 9-km grid 4xday to 84 h Results on web, ftp, LDM
Diversity GFS and LAPS initialization (traditional &
variational) GEFS boundary conditions Multiple microphysics See
Posters 49 by Bernardet et al. 50 by Jankov et al.