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NEXRAD Doppler Radar Network

Project CRAFT: A Test Bed for Demonstrating the Real Time Acquisition and Acrhival of WSR-88D Base (Level II) Data. Presented to UCAR/Unidata Program 12 October 2000 Kelvin K. Droegemeier Center for Analysis and Prediction of Storms and School of Meteorology University of Oklahoma.

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NEXRAD Doppler Radar Network

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  1. Project CRAFT: A Test Bedfor Demonstrating the RealTime Acquisition and Acrhivalof WSR-88D Base (Level II) Data Presented to UCAR/Unidata Program12 October 2000 Kelvin K. DroegemeierCenter for Analysis and Prediction of Storms andSchool of MeteorologyUniversity of Oklahoma

  2. NEXRAD Doppler Radar Network

  3. NEXRAD Facts and Figures • 158 radars (141 in the Continental US) • 120 National Weather Service radars • 26 Department of Defense radars • 12 Federal Aviation Administration radars

  4. WSR-88D Components Radar Data Acquisition

  5. WSR-88D Components Radar Product Generator

  6. WSR-88D Components Principal User Processor

  7. WSR-88D Components Principal User Processor

  8. NEXRAD Data Types • Archive Level I (analog, time domain output) • Level II data (digital base data at full resolution) • Archive Level III (“NIDS” digital products from the Radar Product Generator) • Archive Level IV (at the PUP)

  9. NEXRAD Data Types • Archive Level I (analog, time domain output) • Level II data (digital base data at full resolution) • Archive Level III (“NIDS” digital products from the Radar Product Generator) • Archive Level IV (at the PUP)

  10. NEXRAD Level III (NIDS) Data • 24 products available from all CONUS radars in real time • Provided by 3 commercial vendors • Lowest 4 elevation angles of the radial velocity and reflectivity • 1 degree x 1 km resolution • Values are quantized (e.g., 0-5, 5-10, 10-15)

  11. NEXRAD Data Types • Archive Level I (analog, time domain output) • Level II data (digital base data at full resolution) • Archive Level III (“NIDS” digital products from the Radar Product Generator) • Archive Level IV (at the PUP)

  12. NEXRAD Base (Level II) Data • Full resolution digital data • Full data precision • All tilts • Not quality controlled • 1 degree x 1 km resolution for reflectivity • 1 degree by 0.25 km resolution for radial wind • Not available in real time except for selected sites (more on that later)

  13. Base Data Usage: NSSL Warning Decision Support System on 3 May 1999 Courtesy National Severe Storms Laboratory

  14. Trimmed Detections and Ground Truth Damage Paths Hits (142) Misses (25) FAs (21) Courtesy D. Zittel

  15. 5 April 1999 - Impact of Base Data Initial 700 mb Vertical Velocity Using NIDS Initial 700 mb Vertical Velocity Using Level II Data and SDVR 12 Z Reflectivity Courtesy S. Weygandt and J. Levit

  16. 5 April 1999 - Impact of Base Data 3 hr ARPS CREF Forecast (9 km) Using NIDS Data Valid 15Z 3 hr ARPS CREF Forecast (9 km) Using Level II Data and SDVR Valid 15Z 15 Z Reflectivity Courtesy S. Weygandt and J. Levit

  17. Recording Level III WSR-88D Data • Limited set of products recorded on CD-ROM at the radar site

  18. WSR-88D Level III Data Archival at NCDC Stations 120 Media CD Bytes/media 600 MB Daily Receipts 4 GB Annual Receipts 60 TB

  19. WSR-88D Level III Data Processing Courtesy Steve DelGreco (NCDC)

  20. Level III Requests at NCDC

  21. Recording WSR-88D Level II Data • Not in original plans • Exabyte 8 mm tape recorders added to all radars (1994) as an interim solution

  22. WSR-88D Level II Data Archival at NCDC Stations 158 Media 8 mm tape* Bytes/media 4.8 GB Daily Receipts 165 GB Annual Receipts 60 TB *6-step process with NCDC operating 92 Exabyte tape drives

  23. WSR-88D Level II Data Processing Courtesy Steve DelGreco (NCDC)

  24. Level II Requests at NCDC

  25. WSR-88D Data Archival at NCDC % Rcpts #Sites Level II NWS 64.9 120 Level II DoD 35.7 26 Level II FAA 9.5 12 Total 88D Network 55.7158 Level III NWS 89.5 120

  26. WSR-88D Base Data Archival at NCDC • Currently 42,000 8-mm tapes in archive • 9,500+ copies distributed to date • Cost per tape is nominal ($100 for a radar day) but high for large (multi-year) data sets • Major time delays (2-4 months; human resources) • Archive incomplete • No mechanism for perusing the data base • NOAA spent $768,000 on Level 2 recording system repairs from 6/1/98-6/14/99 • NCDC maintains 92 Exabyte tape systems

  27. Summary: WSR-88D Radar Data • The scientific and operational communities need base data (real time and archived) • Although NIDS data are available in real time from all WSR-88D radars, they are insufficient for many applications (NWP, hydrology) • Degradation of precision • Only the lowest 4 tilts are transmitted • Base data currently are not available in real time • Originally would have been expensive • Presumed large volume of data (10 mbytes/5 min/radar) • Need wasn’t there 10 years ago • The technology and need now exist to prototype the direct acquisition, use, and archival of base data in real time

  28. The Collaborative Radar Acquisition Field Test (CRAFT) • Establish a prototype real time WSR-88D base data acquisition test bed to • Evaluate strategies for compressing and transmitting base data in real time • Develop efficient and cost-effective strategies for direct digital ingest, archive, and retrieval at NCDC • Assess the value of base data in numerical weather prediction • Test web-based data mining techniques for rapid perusal/access of base data by the scientific community

  29. Participants • CRAFT was established by the OU Center for Analysis and Prediction of Storms (CAPS) in collaboration with the • UCAR Unidata Program Office • NOAA WSR-88D Operational Support Facility • University of Washington • CAPS and the NOAA National Severe Storms Laboratory are now jointly coordinating the effort in conjunction with the NEXRAD OSF and UCAR

  30. RIDDS: The Foundation of CRAFT

  31. Technical Strategy Dedicated 56K line ($2000 - $6000/year) Server Cisco 1600 Series Router($2000) Internet Linux PC Unidata LDM ($1500) Users At the radar site WSR-88D RIDDS Repeater Hub

  32. Original CRAFT Network

  33. Sharing Data from Multiple Sources via Cooperating LDMs Courtesy D. Fulker, Unidata

  34. Technical Highlights • We added to LDM in-line compression/decompression (BZIP2 off-the- shelf algorithm) • maximum 16:1 in clear air • about 8:1 in the worst case • average of about 12:1 • Maximum aggregate data rate is 15 Mbytes/radar/5 min uncompressed = 48 Mbits/sec compressed for entire national network • bandwidth isn’t the issue, but rather topology, quality of service, and data storage • one year’s worth of compressed data from NWS radars is about 10 petabytes

  35. Technical Highlights • Compression now being improved (hope for > 20:1) • LDM relays data to other nodes • unlimited system growth • redundancy • Simultaneous data transmission to multiple users • Single point of failure (modem is backup)

  36. Real Time Management and Reliability: >95% http://traffic.onenet.net/

  37. Real Time Management and Reliability: >98% Steve Goodman, NASA/MSFC

  38. CRAFT Phase I: Proof-of-Concept

  39. Internet2 and Abilene • Internet2 is ... • a project, led by universities, to develop advanced internet technology and applications vital to the research and education missions of higher education • big commitment • member universities have committed over $70 million per year in new investment on their own campuses • corporate members have committed more than $30 million over the life of the project

  40. Internet2 and Abilene • Abilene is ... • an advanced backbone network testbed • that connects regional gigaPoPs • supports Internet2 applications development • that is focused exclusively on university research and education • that is developing next generation operational and quality of service capabilities

  41. Abilene NetworkJanuary 1999 Abilene Router Node Abilene Access Node Operational January 1999 Planned 1999 Seattle Cleveland New York Sacramento Denver Indianapolis Kansas City Los Angeles Atlanta Houston

  42. New Concept: Abilene/Internet2 + NEXRAD

  43. New Concept: Abilene/Internet2 + NEXRAD

  44. New Concept: Abilene/Internet2 + NEXRAD

  45. New Concept: Abilene/Internet2 + NEXRAD U-WA NCEP AWC NCAR/FSL NCDC OU TPC

  46. Logical Network Topology Adapted from D. Fulker, UCAR

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