1. Transition of Radar Refractivity to Operational Radars OS&T Briefing, 6 April 2004 Interested parties: NCAR, McGill University, NEXRAD Office of Science and Technology, Federal Aviation Administration, and University participants??

2. REFRACTT Refractivity Experiment For H2O Research And Collaborative operational Technology Transfer

3. Convergence boundaries 22:57 UTC Moisture gradients and convergence boundaries associated with thunderstorm development, June 12, 2002 Convergence boundaries 22:57 UTC Moisture gradient 23:27 UTC 00:01 UTC 00:31 UTC 00:40 UTC Forecasting Challenge: Tracking the “pockets” of boundary layer moisture so critical for convection initiation and growth.

4. Why REFRACTT Demonstrate feasibility on operational radars and motivate NWS and FAA to install refractivity on WSR-88D and TDWR Demonstrate forecast improvement in models and very short period forecasting techniques over a larger domain Improve basic understanding of the role of water vapor in convective storm initiation and storm evolution This is technology transfer of IHOP results to the operational community

5. 100 km -100 km 0 km -100 km0 km100 km S-Pol Radar Boundary WSR-88D’s TDWR Radars Satellite Derived Products: CAPE, CIN LI, Precipitable Water, Soundings Satellite FOV Surface Mesonets NWS/ResearchSounding s AERI: ARM/CART TV Radar (Local Station) Spring 2006 REFRACTT Refractivity Experiment For H 2 0 Research And Collaborative operational Technology Transfer Install refractivity on the national network of radars Oklahoma

6. Future: Install refractivity on all available operational radars λ = 5 cm P T = 250 kw 0.5° pencil beam λ = 10 cm P T = 1000 kw 1.4° x 5° fan beam FAA Radar Networks

7. Cost Function Old VDRAS Boundary Layer Winds Test technique using IHOP data to produce stability fields (CAPE, CIN, and moisture) Test use of VDRAS stability fields in the Auto-Nowcaster Assimilation of Refractivity into VDRAS New equation Juanzhen Sun

8. Refractivity Hourly HRLDAS Evaporation (mm) 18:00 Refractivity 16:00 Refractivity Soil Moisture 16:00 Soil Moisture 18:00 High Resolution Land Data Assimilation System (HRLDAS) Comparison of Refractivity Observations with IHOP 25 May 2002 Collaborative studies with Fei Chen

9. Data Processing: IHOP “Climatology” Broad WNW-ESE refractivity and daily N gradient observed. Mimics (reflects?) climatological moisture gradient in the area.

10. Small-Scale Structure of N Lesser variability in along-wind direction than across: More mixing in along-wind direction via surface friction? More advection-driven E-W gradients (across wind).

11. Timeline 20032004 200520062007 Prototype Development Refractivity on S-Pol’s RVP8 Prototype development on TDWR and ASR-9 ORDA (RVP8) installation Prototype installation and testing on NSSL’s KOUN Prototype installation and testing on ROC’s KCRI Operational Radar Refractivity Test

12. End

13. Results from IHOP June 12 case study S-Pol refractivityVDRAS convergence field at z=0.187 km

14. Retrieved water vapor fields for the first three model levels Z=0.187 km Z= 0.562 km Z=0.937 km

16. Where are we currently ? Received the support of the NEXRAD TAC at the 28 October 2003 meeting. Coordinating with Bob Saffle on writing documentation for NWS Stage 1 and Stage 2 documents Weber and Parker (MIT/LL) have received high level (verbal not monetary) support for testing the refractivity technique on the TDWR testbed radar in OKC. Submitted a preliminary letter of intent to NCAR/ATD to request the SPol radar for REFRACT 2006

17. Piggy-back on the HEAT 2005 Experiment? -Install refractivity on CHILL and the ?? Radar

18. NCAR SPol Ground Clutter Map Oklahoma Panhandle – IHOP2002 Would like to see similar by-pass filter maps for selected NEXRAD radar sites. Cheryl Stephenson and Dave Zittel at ROC have been contacted.

19. GROUND CLUTTER PATTERNS OKC TDWR TESTBED SITE 50 km range ring

21. Observations of a Gust Front Reflectivity Refractivity