NEXRAD Turbulence Detection Algorithm Implementation in the ORPG (CCR NA06-09601)

1. NEXRAD Turbulence Detection Algorithm Implementation in the ORPG (CCR NA06-09601) Gary Blackburn, Steven G. Carson, John K. Williams NCAR Research Applications Laboratory NEXRAD SREC Meeting, Norman, OK May 2, 2006

2. NTDA background • Developed and implemented at NCAR under Technical Direction and funding from the FAA Aviation Weather Research Program (AWRP) • Goal: Supply in-cloud turbulence detection data for • the FAA’s planned Graphical Turbulence Guidance Nowcast (GTGN) product, to run at NCEP and be disseminated via the FAA’s Aviation Digital Data Service (ADDS) • other interested users and displays • Benefits: • improved aviation situational awareness, airspace utilization, and safety (FAA and Air Force) • GTGN schedule • FAA AWTT “D3” (experimental) approval November, 2008 • FAA AWTT “D4” (operational) approval November, 2009 • deployed on Aviation Digital Data Service (ADDS) in early 2010

3. Polar Data Available to WARP, CIWS, ITWS, AWIPS NEXRAD Turb. Detection Algorithm CONUS 3-D EDR Grid (at NCEP) EDR Grids Available to Other Users Conv Wx Nowcasts Integrated Turbulence Diagnosis and Nowcast Algorithms(at NCEP) In situ EDR GTG Nowcast (ADDS) Satellite Radar Reflectivity NWP model (WRF) Operational concept The current Graphical Turbulence Guidance product forecasts clear-air turbulence above 20,000 ft. • Operational GTG: http://adds.aviationweather.gov • Experimental GTG: http://weather.aero

4. Goals/requirements addressed • NEXRAD TAC Active Technical Need TN-17, “Turbulence analysis techniques” • Original WSR-88D turbulence detection requirement • Various FAA reports, plans and guidance documents • Office of the Federal Coordinator for Meteorology (OFCM) National Aviation Weather Program Strategic Plan (April 1997) • Commercial Aviation Safety Team Turbulence JSAT Report (January, 2001) • FAA Aviation Weather Mission Needs Statement #339 Attachments 2 & 5 (June 2002) • Commercial Aviation Safety Team JSIT report Enhancements 64, 65, 68, 72, 76 (July 2004) • FAA Flight Plan 2004-2008, Objective 5: “Reduce cabin injuries caused by turbulence” • FAA Advisory Circulars 00-30b and 120-88 (November, 2005) • FAA Joint Planning and Development Office (JPDO) Next Generation Air Transportation System (NGATS) vision • ~1300 FAA requirements for turbulence and convection detection and dissemination • FAA Aviation Weather Research Program Technical Direction

5. Description of change • CCR #NA06-09601: “IMPLEMENTATION OF THE NEXRAD TURBULENCE DETECTION ALGORITHM (NTDA) IN THE NEXRAD OPEN RPG” • NTDA is a fuzzy-logic algorithm that • produces eddy dissipation rate (EDR) estimates and associated confidences • generates output for each elevation on polar grids at 1 x 1 km spacing • Targeted for ORPG Build 10.0 • FAA request and NWS approval for NTDA data collection via AWIPS will also be required • Rick Heuwinkel and Gloria Kulesa, FAA, have been contacted regarding this issue

6. NTDA status • Operational demonstration performed in summer 2005 • LDM data from 16 NEXRADs processed and mosaicked • real-time turbulence mosaic display and cockpit uplinks • extensive verification and tuning via comparison to automated aircraft in situ EDR reports • TAC briefings on 21 October 2004 and 21 March 2006 • informal feedback from 21 March 2006 Decision Briefing: NTDA science deemed adequate for operations • NTDA initial implementation and testing in ORPG Build 7.0 completed • ANSI C; currently 95% compliant with coding guidelines • documentation begun • DAR held 20 April 2006 • very helpful technical and procedural guidance obtained from ROC, OS&T, and FAA participants • Significant optimization of CPU usage and product size remains to be done

7. Resource usage evaluation • Test system • 3.6 GHz Xeon processor, 4 GB RAM, 1 MB L2 cache (benchmark performance slightly faster than the 2 GHz Opteron 246 to be fielded) • Red Hat Enterprise Linux 3 • CODE Build 7.0, public edition • Approach • ran ORPG/CODE on 3 test volumes • recorded total CPU time for NTDA • evaluated size of BZIP2-compressed linear buffers for various numbers of data levels

8. Initial resource usage results CPU time per volume VCP 121: 32s VCP 21: 23s VCP 32: 15s Goal: < 10s max VCP 21 compressed product, one volume EDR (256/64/32 levels): 338 / 204 / 153 kB Conf (256/32/16 levels): 358 / 185 / 144 kB Goal: < 100 kB max VCP 21 Reflectivity (first tilt) NTDA EDR NTDA confidence

9. Dependencies • External • polar NTDA EDR and confidence data need to be transmitted and collected via AWIPS • data transmission after each elevation to minimize latency • circuit upgrades may be required to accommodate NTDA data • NCEP will need to ingest NTDA data and run AWRP algorithms to generate the GTGN product • Internal • uses data from the REC • may use data from DQA

10. Programmatic and technical risks • Delay in NTDA deployment or NTDA data inclusion in the AWIPS National List: • NTDA data not available in summer 2008 for GTGN development and testing to support FAA AWTT D3 approval • NTDA data not available in summer 2009 for GTGN operational testing at NCEP to support FAA AWTT D4 approval • FAA approval of the GTGN product could be delayed, or GTGN implemented without NTDA input, diminishing performance • Unforeseen ORDA or ORPG changes: • extensive NTDA software changes required during integration • delayed deployment, or poor algorithm performance • Inadequate transmission bandwidth for NTDA data: • increased dissemination latency • diminished usefulness of the turbulence detection product • adverse effects on the dissemination of other products

11. Proposed schedule 1 June–15 September Algorithm modifications and tuning 15 September Algorithm freeze 3 May–30 September Code and product size optimization 1 October Code freeze 1 October–30 November Intensive code testing, hardening 15 October Second DAR October TAC briefing on algorithm changes, updated verification results 15 November Draft documentation (SS, SRS, AEL, ICD, SDD) completed 5 December IRR 5 January 2007 NTDA code delivered to the ROC

12. Known issues • Implementation • current maximum memory usage is high, at ~46 MB • CPU usage and product size need to be reduced substantially • VCP 121 (MPDA) is not handled ideally • beam indexing is not yet properly accommodated • REC-based confidence and DQA data are not yet integrated • Policy and process • NTDA data collection via AWIPS must be requested by FAA and approved by NWS • Future needs • ORDA and ORPG changes should improve quality and precision of spectrum width data

13. NTDA maintenance and support • Software maintenance • support to be provided by FAA AWRP Advanced Weather Radar Techniques Product Development Team, via NCAR/RAL • appropriate involvement and support from the ROC • Technical and scientific questions • support to be provided by FAA AWRP Advanced Weather Radar Techniques and Turbulence Product Development Teams, via NCAR/RAL

14. Alternative approaches • Implement NTDA demonstration system software or multiple ORPGs running NTDA at NCEP • eliminates WSR-88D baseline integration requirement and data transmission/collection issues, but • substantial effort would be required to maintain the NTDA or multiple ORPGs to accommodate ORDA/ORPG upgrades • polar NTDA data would not be available to other users and displays, or for archival • NTDA developers would not be as naturally “in the loop” on baseline upgrades • eventual NTDA use of spectral data would be complicated • ROC, OS&T, and other NEXRAD experts would not be as naturally involved in NTDA design, implementation, and approval decisions • Add NTDA data to CRAFT/IRaDS data feed