High Resolution Assimilation of Radar Data for Thunderstorm

Forecasting on OSCER Keith A. Brewster, Kevin W. Thomas,

Jerry Brotzge, Yunheng Wang, Dan Weber and Ming Xue

CAPS and School of MeteorologyUniversity of Oklahoma

2007 OSCER Supercomputing SymposiumNorman, Oklahoma, October, 2007

CASA & NEXRAD Radars• CASA NetRad

NSF ERC: Collaborative Adaptive Sensing of Atmosphere– X-Band Dual-Polarization Radars– 30 km nominal range– Dual-Pol attenuation correction– Clutter filter– Collaborative, Adaptive Scanning– Fill-in below coverage of NEXRAD– Toward phased-array panels – low-cost!

• NEXRAD– S-Band Radars– Current Weather Service Operational Radars – 14 covering domain– Data used out to 230 km

CASA NetRad IP1

Southwest Oklahoma

CASA NetRad KFDR NEXRAD

Near Real-Time NWP Runs

CASA & NexRad

CASA Only

NexRad Only No Radars

• Four Runs in Near Real-time

• Hourly output graphics posted to web: http://www.caps.ou.edu/wx/casa

• 9 Weeks in Spring 2007

• 6-hour 1-km resolution forecasts

• Use Reflectivity

• ARPS Model

• ADAS Analysis with cloud analysis and latent heat adjustment

• Run on Parallel Linux Boxes OU OSCER(150 proc/2 runs at a time)

Forecast Domainx = 1 kmnx=603ny=543nz=53

Assimilation Strategy

2210 2220 2230 042200 00

IAU IAU IAU

01 02 03

5.5-hour Forecast40-min Assimilation

IAU

2150

Forecast Model started manually when storms enter the networkor with initial development within the network

Computing - Networking

CASA Radars

NexRad Radars

Other WeatherObservations

Other NumericalWeather Model Data

CASA SOCC

CAPS Ingest Cluster

IDD (Internet)

IDD (Inter

net)

Internet

NFS

OSCER Top DawgHPC

CAPS Webserver

DataFile Archive

Computing – Number CrunchingTopDawgTotal 1024 processorsPentium4 Xeon EM64T 3.2 GHzGigE Network (976 Mbps, latency 9 s)

ARPS Analysis/Forecast150 processors per job (75 nodes)4 forecasts, 2 jobs run at a timeHorizontal Domain Decomposition, MPICH215x10 processors6 - 6.5 h wall for each forecast1 - 1.5 h wall for data processing and analysis~50 GB of data each day created for archive

Summary of 2007 Cases• 21 Sets of Runs for 20 Cases• Weather Summary:

– With Funnels and/or Tornadoes (2)– Squall Lines (8)– Clusters of Cells or Individual Cells (6)– Broken Lines and/or Cells on Boundaries (5)– Precip Area with Synoptic Scale Low (1)

• Some developing, some intensifying, decaying• Wide Range of Time-of-Day

Sample Impact of CASA NetRad Data

NEXRAD Only

NetRad & NEXRAD

ADAS Analysis ofHydrometeorsConverted to ReflectHgt=~250 m AGL

Cross-SectionNEXRAD Only NEXRAD & NetRad

NetRad Low-Level Info

01 Z May 09 Forecast Animation

ReflectivityAll Radars

Refl + VrAll Radars

KTLX (Verif)

40 min - End of Assimilation Period

ReflectivityAll Radars

Refl + VrAll Radars

KTLX (Verif)

40 min - End of Assimilation Period

Stronger Vort

Improved Refl

2-hour Forecast

ReflectivityAll Radars

KTLX (Verif)

Refl + VrAll Radars

2-hour Forecast

ReflectivityAll Radars

KTLX (Verif)

Refl + VrAll Radars

Stronger, Closer

Vorticity During Assimilation

2-3 hr Vorticity Forecasts

2-3 hr Vorticity Forecasts

Triangles:ObservedCirculationsNo

Radar Data

2-3 hr Vorticity Forecasts

Solid Green:NetRad Only

Orange:NexRad Only

Red:Reflectivity Both

2-3 hr Vorticity Forecasts

Radial VelocityData Used fromAll Radars

Four CirculationsTracked in this run

Accomplishments• Completed MPI of ADAS with cloud analysis• Able to process CASA radar

– Automated Data Selection– Data I/O and Quality Control (ref & vel)– Remapping and hydrometeor assignment– Reflectivities are well-handled in model

• Baseline Runs Complete

Ongoing/Future Work• Complete MPI of Vr analysis and run simulations with Vr• Detailed verification of model forecasts

– Comparison of QPF to NSSL 1-km Q2– Comparison of location and strength of forecast circulation

centers vs. radar-observed circulation centers (April 10, May 8/9)• Prepare for 2008 Experiment

– Complete MPI of 3DVAR and comparison of results– Integrate NWP in end-user training– Design near real-time evaluation for integration in

NWC Hazardous WeatherTestbed