1. Hurricane Observation Capability of Future Hurricane Imaging Radiometer (HIRAD) Timothy L. Miller 1, R. Atlas 2, P. G. Black 3, R. E. Hood 5, M. W. James 1, J. W. Johnson 6, L. Jones 6, C. S. Ruf 7, E. W. Uhlhorn 2, and Salem Al-Nimri 6 1 NASA/MSFC, Huntsville, AL 2 NOAA/AOML, Miami, FL 3 SAIC Inc., Naval Research Laboratory, Monterey, CA 4 USRA, Marshall Space Flight Ctr, Huntsville, AL 5 NOAA, Boulder, CO 6 University of Central Florida, Orlando, FL 7 University of Michigan, Ann Arbor, MI Presented to Interdepartmental Hurricane Conference, March 2009

2. Hurricane Imaging Radiometer (HIRAD) Existing 1980s Technology Advanced Technology HIRAD in development Simulated Observations HIRAD utilizes NASA Instrument Incubator Technology: Provides unique observations of sea surface wind, temp and rain Advances understanding / prediction of hurricane intensity Expands Stepped Frequency Microwave Radiometer capabilities Uses synthetic thinned array, RFI mitigation technology of Lightweight Rain Radiometer Univ. of Michigan Univ. of Alabama/Huntsville Univ. of Central Florida NASA NOAA Timothy Miller, PI, NASA/MSFC Earth Science Eric Uhlhorn, co-PI, NOAA AOML/Hurricane Research Division Robbie Hood, NOAA UAV Program Mgr, co-I and former PI Linwood Jones, University of Central Florida Christopher Ruf, University of Michigan NASA/UAH Engineering & Spacecraft Project Management Peter Black, NRL/SAIC Robert Atlas, NOAA/AOML Government, Academic Team Passive Microwave C-Band Radiometer Freq: 4, 5, 6 & 6.6 GHz, Version 1 H-pol for ocean wind speed, Version 2 fully polarimetric for ocean wind vectors 20 km Aircraft Altitude Performance Characteristics EIA: 0°- 60°, Spatial Resolution: 2-5 km, Swath: ~70 km Observational Goals: Wind Speed 10 - >85 m/s Rain Rate 0 - > 100 mm/hr 2000 km Swath 70 km

3. What is HIRAD? (Hurricane Imaging Radiometer) Passive C-band radiometer Objective: To measure strong ocean surface winds through heavy rain from air or space-based platform –With cross-track resolution in addition to along-track –Swath width ~60 o (~3 x altitude) –Winds dynamic range: 10 – 100 m/s, through rain up to ~100 mm/hr –Would complement scatterometers and lidars Technology heritage: –SFMR (Stepped-Frequency Microwave Radiometer) currently flying on reconnaissance aircraft (no cross-track resolution) –NASA Instrument Incubator: Thinned array antenna, along-track real aperture, synthetic cross-track aperture Status: –Brassboard (bench lab) version of single-polarization (wind speed only) instrument successfully tested in anechoic chamber last August –Single-polarization aircraft instrument to be completed Sept. 2009 Partnership: –Project leadership, PI, and engineering at NASA/MSFC –Technology, engineering, and science lead partners: NOAA/HRD (Uhlhorn), Univ. Central Florida (Linwood Jones), Univ. Michigan (Chris Ruf), Univ. Alabama Huntsville (project & engineering support)