An Overview of the Hurricane Imaging Radiometer (HIRAD)

Robbie Hood, Ruba Amarin, Robert Atlas, M.C. Bailey, Peter Black, Courtney Buckley, Shuyi Chen, Roger DeRoo, Salem El-Nimri,

Steve Gross, Christopher Hennon, Glenn Hopkins, Mark James, James Johnson, Linwood Jones, Frank LaFontaine, Timothy Miller,

Christopher Ruf, David Simmons, Eric Uhlhorn, and Joe Cione

Team Roles

• NASA PI – Robbie Hood NOAA PI – Eric Uhlhorn

• Technical Advisory Committee – Joe Cione, Marty Kress, Joe Casas, Mark Boudreaux

• Engineering Partners – M.C. Bailey, Roger DeRoo, Steve Gross, Mark James, James Johnson, Linwood Jones, Christopher Ruf, and David Simmons

• Science Partners - Ruba Amarin, Robert Atlas, Peter Black, Courtney Buckley, Shuyi Chen, Salem El-Nimri, Christopher Hennon, James Johnson, Linwood Jones, Frank LaFontaine, Timothy Miller, Christopher Ruf

Technology Transfer Operational Reconnaissance Hurricane Aircraft (optional)

Unmanned Aerial Vehicle Demonstration (optional)

Technology Brassboard Demonstration in Laboratory

Satellite Demonstration of Improved Hurricane Ocean Surface Vector Winds and Rain Rate

HIRAD Technology Investment Roadmap

Aircraft Demonstration

Overview

Univ. of Michigan

Univ. of Alabama/Huntsville

Univ. of Central Florida

NASA

NOAA

HIRAD Design Team

C-band (4-7 GHz) frequencies

Synthetic thinned array radiometer (STAR)

Pushbroom imager

Single polarization for ocean wind speed

Dual polarization for ocean vector wind

HIRAD Development Timeline

HIRAD Description

Sensitivity of WindSat 6.8 GHz

0 10 20 30 40 50 60 700.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

H*Wind (m/s)

6.8

GH

z H

-pol

Em

issi

vity

Surface Emissivity vs. Ground Truth Wind Speed

Based on 2006 H*Wind analysis of Hurricanes Dennis, Katrina, Rita

Technical Overview

Utilization of NASA Earth Science Office Technologies

•Synthetic thinned aperture radiometer•Digital correlation in field programmable gate array•Radio Frequency Interference mitigation•Sensor Web information technology Engineering concept

with aircraft fixtures

Sideview of antenna element

HURRICANE FRANCIS NATURE RUN

=20 mm/hr

With SFMR With HIRAD (11 km)

Double-headed arrow indicates HIRAD swath width

Observing Systems Simulation Experiment

Results presented by Tim Miller at AMS Annual Meeting (Jan 08) and AMS Hurricane Conference (Apr 08)

SIMULATED DATA FROM NATURE RUN

Observation Simulated Comment

QuikSCAT

SFMR (aircraft ocean surface winds sensor)

Winds along ground track; no cross-track structure

Flight level winds Not used

Dropsonde windsDrops in eyewall and at storm center from aircraft

Airborne Doppler Radar

Future work

GOES cloud windsUsing actual data for location (relative to storm center), nature run data plus error for wind values

Buoys, ships, coastal sensors

HIRAD 3 aircraft altitudes, satellite

Aircraft OSSE using H*Wind

109 117 121

82 109125

Nature Run in H*Wind Simulated without HIRAD

Simulated with HIRAD at 3 km Simulated with HIRAD at 20 km

Satellite OSSE using H*Wind

109 117 121

82 109125

Nature Run in H*Wind Simulated without HIRAD

Simulated with HIRAD at 350 km

Preliminary Mission Study

Performance Characteristics for HIRAD

Example of sensor swath coverage of an Atlantic hurricane (yellow symbol) over a typical 24-hour period. XOVWM swath is red and HIRAD swath is blue.

CHARACTERISTIC

frequency (GHz) 4 5 6 7 4 5 6 7altitude (km)# of STAR sub-arrays# of synthesized baselines

Receiver Design bandwidth (MHz) 85 60 60 150 85 60 60 150

Nadir(km)(geometric mean of principle plane) 2.5 2.1 1.7 1.5 7.7 6.1 5.1 4.430 deg cross track off-nadir (km) 3.4 2.7 2.3 2.0 10.0 8.0 6.6 5.760 deg cross track off-nadir (km) 9.9 8.0 6.7 5.8 28.0 22.4 18.6 16.1

Brightness NEDT (K) (assuming 290K scene brightness) 0.19 0.25 0.27 0.22 0.90 1.27 1.53 1.09

SPACECRAFT (5m aperture)AIRCRAFT (1m aperture)

20 350System Design

Spatial Resolution

2520836

10

Potential Benefits

• Imagery– Wind Speeds (10 – 85 m/s or greater)– Rainrate (0-50 mm/hr or greater)– All weather sea surface temperatures

• Aircraft– Suitable for multiple aircraft– Improved spatial coverage

• Satellite– Developing consistent record of hurricane intensity for future climate

monitoring– Expanding information available to developing countries with limited

observational assets