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??

REFRACTT

Refractivity Experiment For H2O Research And Collaborative operational Technology Transfer

Convergence boundaries

22:57 UTC

Moisture gradients and convergence boundaries associated with thunderstorm development, June 12, 2002

Convergence boundaries

22:57 UTC

Moisture gradient

Moisture gradient

23:27 UTC23:27 UTC 00:01 UTC00:01 UTC 00:31 UTC00:31 UTC 00:40 UTC00:40 UTC

Forecasting Challenge: Tracking the “pockets” of boundary layer moisture so critical for convection initiation and growth.

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

100 km

-100 km

0 km

-100 km 0 km 100 km

S-Pol Radar

Boundary

WSR-88D’s

TDWR Radars

Satellite Derived Products: CAPE, CINLI, Precipitable Water,Soundings

Satellite FOV

Surface Mesonets

NWS/ResearchSoundingsAERI: ARM/CART

TV Radar (Local Station)

Spring 2006

REFRACTT

Refractivity Experiment For H20 Research And Collaborative operational Technology Transfer

Install refractivity on the national network of radars

Oklahoma

Future: Install refractivity on all available operational radars

ASR-9s

ASR-9s

λ = 5 cmPT = 250 kw0.5° pencil beam

λ = 10 cmPT = 1000 kw1.4° x 5° fan beam

TDWRs

TDWRs

FAA Radar Networks

Cost Function

Old t

orz

orv ZqGvwvuFJ

,

))(()),,((

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 t

ovN

orz

orv NqTpHZqGvwvuFJ

,

),,(())(()),,((

Juanzhen Sun

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

IHOP25 May 2002

Collaborative studies with Fei Chen

Data Processing: IHOP “Climatology”

Broad WNW-ESE refractivity and daily N gradient observed.Mimics (reflects?) climatological moisture gradient in the area.

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).

Timeline

2003 2004 2005 2006 2007

Prototype DevelopmentRefractivity 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

End

Results from IHOP June 12 case study

S-Pol refractivity VDRAS convergence field at z=0.187 km

Retrieved water vapor fields for the first three model levels

Z=0.187 km

Z= 0.562 km Z=0.937 km

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

Piggy-back on the HEAT 2005 Experiment?

-Install refractivity on CHILL and the ?? Radar

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.

GROUND CLUTTER PATTERNS OKC TDWR TESTBED SITE

50 km range ring

Observations of a Gust Front

Reflectivity Refractivity