Transcript The REFRACTT experiment/demonstration (Roberts)

Transition of Radar Refractivity to
Operational Radars
Interested parties: NCAR, McGill University, NEXRAD Office of Science
and Technology, Federal Aviation Administration, and University
participants??
OS&T Briefing, 6 April 2004
REFRACTT
Refractivity Experiment For H2O Research And
Collaborative operational Technology Transfer
Forecasting Challenge: Tracking the “pockets” of boundary
layer moisture so critical for convection initiation and growth.
Moisture
gradient
Convergence
boundaries
00:40
22:57
00:31
00:01
UTC
23:27UTC
UTC
Moisture
gradient
Convergence
boundaries
00:31
22:57
00:01
00:40
UTC
23:27UTC
UTC
Moisture gradients and convergence boundaries associated with thunderstorm
development, June 12, 2002
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
Boundary
Spring 2006
Oklahoma
Install refractivity on the national network of radars
S-Pol Radar
0 km
WSR-88D’s
TDWR Radars
TV Radar (Local Station)
Surface Mesonets
NWS/ResearchSounding
s
AERI: ARM/CART
-100 km
-100 km
0 km
REFRACTT
Refractivity Experiment For H20 Research And
Collaborative operational Technology Transfer
100 km
Satellite
FOV
Satellite Derived
Products: CAPE, CIN
LI, Precipitable Water,
Soundings
Future:
Install refractivity on all available operational radars
FAA Radar Networks
ASR-9s
λ = 10 cm
PT = 1000 kw
1.4° x 5° fan beam
TDWRs
λ = 5 cm
PT = 250 kw
0.5° pencil beam
Assimilation of Refractivity into VDRAS
Juanzhen Sun
VDRAS Boundary Layer Winds
Cost Function

Old
J   v ( F (u, v, w)  vro )   z (G (qr )  Z o )
 ,t

New equation

J   v ( F (u, v, w)  vro )   z (G (qr )  Z o )   N ( H ( p, T , qv )  N o
 ,t
• Test technique using IHOP data to produce stability fields (CAPE, CIN,
and moisture)
• Test use of VDRAS stability fields in the Auto-Nowcaster

Comparison of Refractivity Observations with
High Resolution Land Data Assimilation System (HRLDAS)
Refractivity
16:00
Hourly HRLDAS Evaporation (mm)
16:00
Collaborative
studies with
Fei Chen
Refractivity
18:00
IHOP
25 May 2002
Refractivity
Soil Moisture
18:00
Soil Moisture
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
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
2004
2005
2006
2007
End
Results from IHOP June 12 case study
S-Pol refractivity
VDRAS convergence field at z=0.187 km
Z=0.187 km
Retrieved water vapor fields
for the first three model
levels
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