NASA/George C. Marshall Space Flight Center

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Hurricane Imaging Radiometer (HIRAD) operations and results from GRIP

PI: Timothy L. Miller, NASA/MSFC

Co-I’s:Linwood Jones, UCFChris Ruf, U MichEric Uhlhorn, NOAA/AOML

GRIP Science Team Meeting, 6 June 2011

NASA/George C. Marshall Space Flight Center

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HIRAD Contributors

Lead Systems Engineer: Mark James, NASA/MSFCProject Coordinator: Courtney Buckley, NASA/MSFC/USRAAntenna design: M.C. BaileySystems engineering: David Simmons, UAHuntsvilleRF systems engineering: Roger DeRoo, U MichSoftware engineering: William Cleveland, UAHProject Initiator: Robbie Hood, NOAA (formerly NASA/MSFC)Level I data analysis: Sayak Biswas, Univ. Central FloridaMission ops: Lori Schultz (UAH), Brent Roberts (NASA/MSFC)Radiative transfer modeling: Salem El-Nimri, Ruba Amarin (both UCF)Presentation preparation: Cathy May, UCFEngineering consultation: James Johnson, UCFScience consultation: Peter Black, Robert Atlas, Cerese Albers, T. N. Krishnamurti

NASA/George C. Marshall Space Flight Center

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HIRAD Capabilities

• Passive C-band microwave radiometer (4, 5, 6, 6.6 GHz) to measure wind speed and rain rate over ocean surface

• HIRAD flew on the WB-57 during GRIP and will fly on the Global Hawk as part of HS3

• HIRAD’s unique contribution: Measurement of rain rate and hurricane-strength winds, even through heavy rain

– Wind speed ~ 5 – 85 m/s– Rain rate ~ 0 – 100 mm/hr– Swath width ~3x altitude

• Operations: NHC desires better definition of max wind speed and location

• Science Hypothesis: Short-term forecasts of intensity and structure will be improved by assimilation of HIRAD data

Simulation

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HIRAD on the NASA WB-57

NASA/George C. Marshall Space Flight Center

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Hurricane Earl Best Track

HIRAD flight

NASA/George C. Marshall Space Flight Center

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Earl’s actual track was west of forecasts

This resulted in Earl being accessible from Tampa, although planning was a challenge!

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HIRAD flight

Hurricane Earl Max Wind Speed

NASA/George C. Marshall Space Flight Center

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HIRAD TB Images at 4.0, 5.0 and 6.6 GHzalong Northbound Earl Overpass

4.0 GHz 5.0 GHz 6.6 GHz

NASA/George C. Marshall Space Flight Center

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WB-57/HIRAD flight over Earl (1 Sept 2010)

SFMR

SFMR

Storm-centric coordinate system

SFMR is the operational NOAA instrument. Tb is expected to agree only at the nadir point.

NASA/George C. Marshall Space Flight Center

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0 10 20 30 40 50 60 70 8040

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180WEST - 4&5 GHz

HIRAD Tb@ 4GHzHIRAD Tb@ 5GHzModel Tb@ 4GHzModel Tb@ 5GHz

SFMR Wind +50 (m/s)

SFMR Rain +50 (mm/hr)

HIRAD/SFMR West Leg Overpass

stop startSFMR Flt Dir

“Model” data are Tb’s computed from SFMR wind & rain fields

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Karl Best Track

Storm location during HIRAD flights indicated by triangles

NASA/George C. Marshall Space Flight Center

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Hurricane Karl Max Wind Speeds

HIRAD flight

HIRAD flights

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HIRAD flights over Karl

Sept 16HIRAD 19:00 – 21:55

Sept 171745-2015 UTCStorm center indicated 18 Z

Sept 14Storm center indicated at 00 Z

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HIRAD flights over Karl

Sept 14 Sept 16Adjusted for storm motion

Sept 171745-2015 UTC

NASA/George C. Marshall Space Flight Center

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HIRAD 5 GHz Tb on Flight Tracks for Karl

Storm-centric Longitude (deg)

Sto

rm-c

entri

c La

titud

e (d

eg)

Leg 8

Leg 10

Leg 6

Univ. of Central Florida

NASA/George C. Marshall Space Flight Center

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HIRAD flight over Karl on 16 Sept

-1.5 -1 -0.5 0 0.5 1-1

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deg)

5GHz [Karl,09/16/2010]

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-1.5 -1 -0.5 0 0.5 1-1

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4GHz [Karl,09/16/2010]

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-1.5 -1 -0.5 0 0.5 1-1

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6.6GHz [Karl,09/16/2010]

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5 GHz

• Excess Tb removes the incidence angle variation

Univ. of Central Florida

NASA/George C. Marshall Space Flight Center

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HIRAD WS

HIRAD Rain SFMR Rain

SFMR WS

Bad retrievals, to be corrected after final Tb calibration

HIRAD and SFMR (analysis) Wind Speed & Rain Rate Comparisons

NASA/George C. Marshall Space Flight Center

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Karl Leg 6: WS & RR Time Series (HIRAD & SFMR)

100 200 300 400 500 600 7000

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SFMRHIRAD

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SFMRHIRAD

Rain Rate, mm/hr Wind Speed, m/s

eye

eye

Univ. of Central Florida

NASA/George C. Marshall Space Flight Center

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Summary

• The WB-57, with HIRAD aboard, flew once over Earl and 3 times over Karl during GRIP

• The Earl flight and the 16 Sept Karl flight look to be the most likely to provide important contributions to the GRIP mission dataset

– These two flights have priority in data processing and analysis– High-res wind speed and rain rate images provide snapshot of the complete

inner core in a single aircraft pass (Leg 10 of Karl, 16 Sept)

• Continuing to develop data processing methodology to establish and maintain calibration in all channels and sub-bands

– See poster by Ruf et al.

• Meanwhile, we have developed a methodology for calibrating HIRAD Tb’s against SFMR, and we are producing wind speed and rain rate retrievals that show consistency with SFMR, but with value-added details

– See poster by Jones et al.

• Targeting release of Tb and wind/rain data for Earl and 16 Sept Karl on Aug 1