Atmospheric Winds and Rain Obs - ofcm.gov session2...(60 rpm) Simultaneous, MultiBeam- Doppler/Reflectivity Profiling Specifications . Frequency: C -band & Ku-band . Polarization:

60th IHC – Mobile, Alabama 20 – 24 March 2006

Atmospheric Winds and Rain Obs - Coming to Your Neighborhood Soon!

OUTLINE

Problem Definition ABL and Surface Wind Fields Precipitation Next Steps Acknowledgements:

NOAA AOC (Sean McMillan)

60th IHC – Mobile, Alabama 20 - 24 March 2006

Project Objectives Develop an operational system for

continuously mapping:

Lower ABL wind field.

Ocean surface wind field.

Precipitation field. Within tropical cyclones and rain bands.


IWRAP Measurement Technique

Conical Scan (60 rpm)

Simultaneous, Multi-Beam Doppler/Reflectivity

Profiling

Specifications

Frequency: C-band & Ku-band Polarization: VV, HH Beam Incidence Angles: 30, 35, 41.5, 50 Altitude Range: 500 – 8000 m Range Resolution: 15, 30, 60 & 120 m

Swath Coverage ~ 55 deg. Incidence Proportionally not to scale.


IWRAP Wind Products Tangential Winds – 13 Sept. 2003, Inbound Leg

Radial Winds – 13 Sept. 2003, Inbound Leg

30 35 40 45 50 55 60 65 Radial distance from storm center (km)


kts

160

120

80

40

kts

40

0

-40

-60

Alti

tude

(m)

1000

300

2000

Alti

tude

(m)

1000

300

2000


Volume Backscatter Profiles: - Ocean Surface Backscatter Contamination

Outer Side

Nadir Side

θo

Range Gate

(N)(N)

Range Gate

(N-1)

(N-1) (N)

(N-1)

Alti

tude

Distance from Aircraft Track

Antenna Pattern Main Lobe

Incidence Angle

Nadir Side OuterSide

Gai

n (d

Bi)

θo

(N-1)

(N)

Range Gates (N & N-1)


Volume Backscatter Profile (with Surface Contamination)

Ocean Surface

Echo

Ocean Surface

Contamination


Doppler Spectral Profile

Ocean Return

Return from Precipitation / Winds

22 September 2005 – 19:55 GMT

1493 1217 942 667 391 116 -159 Altitude (m)

220

110

0

-110

-220

Rad

ial D

oppl

er V

eloc

ity (k

ts)

dB

-5

-10

-15

-20

-25


Lower Atmospheric Boundary Layer

Ocean Return



380

250

120

-10

-140

Alti

tude

(m)

Radial Doppler Velocity (kts) -220 -110 0 110 220

dB

20

15

10

5

Spectral Filtering Algorithm


Precipitation Profile to Surface

Surface

Ocean Surface Backscatter


Volume Backscatter Profile - Spectral Filtering Applied


ABL Profile with Spectral Filtering Al

titud

e (m

)

Wind Speed (kts) 0 20 40 60 80 100

1000

100


Further Improvements: - Leading to an Operational Solution

More efficient antenna design – ~15 % reduction in beamwidth – 4 db gain improvement

Unique Single RF Channel Design – 10 dB improvement in sensitivity. – Smaller, lighter and less expensive.

Frequency Diversity Doppler technique – Decouples range and Doppler ambiguities.


Next Step: - Advanced Wind and Rain Airborne Profiler

Proposed SBIR Phase II Develop AWRAP system

– Real-time spectral processor Map ABL winds to within ~ 50 m of surface. Map ocean surface wind field in the presence of precipitation.

– New transceiver & antenna 15 dB more sensitive (~15 dBZ minimum reflectivity) One-third the components.


Our Mission Statement

A Happier, Smarter, Better World ! Advances in technology are, and will continue to, bring the research, forecast, emergency management and operational communities closer together.

The end result, we all become smarter quicker and the public receives better and better and better forecasts ! ! !


NASA IIP HIWRAP

NUMBER 5

NASA High Altitude Wind and Rain Profiler Highlights

- 60+ kft flight altitude - Design for Global Hawk UAV - Map winds from troposphere to the surface. - Clouds and precipitation. - Modular design for transition to other aircraft. -Long duration mission (24+ hrs) - Solid-state design reduces fabrication and operational costs


Lower Atmospheric Boundary Layer

Ocean Return



380

250

120

-10

-140

Alti

tude

(m)

Radial Doppler Velocity (kts) -220 -110 0 110 220

dB

20

15

10

5

Original Measurements

Spectral Filtering Algorithm


Precipitation Profile to Surface

Surface

-220 -110 0 110 220

Radial Doppler Velocity (kts)

380

250

120

-10

-140

Altit

ude

(m)


IWRAP Wind Products (cont.) Divergence – 13 Sept. 2003, Inbound Leg

Vorticity – 13 Sept. 2003, Inbound Leg

30 35 40 45 50 55 60 65


m/s

0.4

0.2

0.0

-0.2

-0.4

4 2 0 2

-4

Alti

tude

(m)

1000

300

2000

Alti

tude

(m)

1000

300

2000

x10-3 s-1


Precipitation Retrievals

(modified)

Documents

Atmospheric Winds and Rain Obs - ofcm.gov session2...(60 rpm) Simultaneous, MultiBeam- Doppler/Reflectivity Profiling Specifications . Frequency: C -band & Ku-band . Polarization: