Radar Sea Level Pressure Remote Sensing for Improvements in Hurricane Predictions 04 March 2008 Charleston, SC Qilong Min Roland Lawrence Bing Lin, Yongxiang Hu, Steven Harrah, and Dion Fralick Langley Research Center Hampton, VA Session 3: Observing the Tropical Cyclone and its Environment

62 nd IHC Radar Sea Level Pressure Remote Sensing for Improvements in Hurricane Predictions OUTLINE Need & Benefits Measurement Development Status Conclusion

62 nd IHC moored buoy dropsonde Off-Shore Air Pressure Measurements Radar Sea Level Pressure Remote Sensing for Improvements in Hurricane Predictions Current operations require in situ measurement (few buoys & dropsonde) - sparse measurements in time and space - exposes air crews to a variety of dangers Greatly improves hurricane forecasts (intensification and track) Improved understanding of global pressure field (dynamics and interactions) - large area coverage & relatively rapid revisit intervals - lessen operational dangers & costs (long-term) drift buoy Added Benefits of Remotely Sensed Measurements

62 nd IHC Example Benefits (Ivan’04 & Fran’97) 998.7mb 350 km landfall error reduced to < 100 km actual track with P data Control 951.5mb pressure variability: 882~1020mb error: 1.5mb (47 mb change) no P data with P data Radar Sea Level Pressure Remote Sensing for Improvements in Hurricane Predictions 72hr Forecasts

62 nd IHC Run Distance Error (km) SLP (hPa) Max Winds (kt) Landfall Time (UTC) Observation :00 Aug. 25-c :00 Aug. 25-p :00 Aug. 26-c :00 Aug. 26-p :00 Improvements in hurricane forecasts are demonstrated using press. measurements compared with control predictions and the observed track of Katrina. Key predictions in hurricane intensity and track are significantly improved using remotely sensed pressure measurements (p) compared to controlled models (c). Aug 29 Radar Sea Level Pressure Remote Sensing for Improvements in Hurricane Predictions Example Benefits (Katrina)

62 nd IHC Oxygen in the atmosphere attenuates the transmitted signal – less at lower freq. and more at higher freq. The amount of attenuation is directly related to barometric pressure and altitude. f or 1/ P Rec Attenuation Calibrated P Rec w/o Attenuation Aircraft/Spacecraft-Based Q-Band (50-56GHz) Radar Radar Sea Level Pressure Remote Sensing for Improvements in Hurricane Predictions Measurement Concept Radar Attenuation by Oxygen Barometric Sensor (RAOBS) T/R Several (1-6), Narrow-Band (~100MHz) Signals

62 nd IHC Most of the variability (shown here) is due to global atmospheric profile variations: temperature, water vapor, clouds, etc. Radar Sea Level Pressure Remote Sensing for Improvements in Hurricane Predictions Simulated Radar Results P R ( 1 ) P R ( 2 )

62 nd IHC Ground Tests (LaRC) RAOBS PoC Instrument Installed on Mobile Radar Lab Calibration Target nearly spherical reflector ~300m clear range Projected Beamwidth Projected Beamwidth Calibration Target nearly spherical reflector ~300m clear range Radar Sea Level Pressure Remote Sensing for Improvements in Hurricane Predictions Radar Attenuation by Oxygen Barometric Sensor (RAOBS)

62 nd IHC Radar Sea Level Pressure Remote Sensing for Improvements in Hurricane Predictions Varina-Enon Bridge I-295 South of Richmond, VA Approx. 150’ above James River Ground Tests Measure Water NRCS Over Wide Inc. Ang. Support Satellite Design Supported by VDOT

62 nd IHC Port Side View C E N T E R HELICOPTERS, INC. Rail Mount Box Frame Antennas Internal Rack (VNA) Cable Routing Bell 407 Radar Sea Level Pressure Remote Sensing for Improvements in Hurricane Predictions Flight Hardware Installation RAOBS PoC Instrument Flight Tests Q3 FY08

62 nd IHC Radar Sea Level Pressure Remote Sensing for Improvements in Hurricane Predictions ±10 o LEO (705 km) RAOBS Satellite Concept T orbit ~98 min 250 km ~ ½ o 6 km Design Est.: Mass Power & DL Comm. TBD – FY’08

62 nd IHC Conclusions Radar Sea Level Pressure Remote Sensing for Improvements in Hurricane Predictions RAOBS Concept of Operation Instrument - Validated RAOBS Measurement Concept - Completed Ground Tests - Developed Flight Installation (awaiting FAA cert) - Looking for additional flight opportunities RAOBS operational model shows significant improvements to our understanding of global pressure fields (dynamics and interactions) Significant improvements to hurricane forecasts (intensification and track) - Improves forecast reliability - Increases warning times - Decreases social/economic impact Beginning satellite design and subsystem definitions - Looking for collaborative partners / future satellite projects