Developed by Eastwood Im Jet Propulsion Laboratory Nexrad In Space Developed by Eastwood Im Jet Propulsion Laboratory

System Parameters Frequency (GHz) 35.605 Range Resolution (m) 250 Horizontal Resolution (km) 12 Pulse Compression Sidelobes (dB) -55 Pulse Length (microsec) 60 Pulse Repetition Frequency (kHz) ~ 3 Bandwidth (MHz) 2 Sample Frequency (MHz) 10 Antenna Aperture (m) 28 Beamwidth (deg.) 0.02 Minimum Detectable Reflectivity (dBZ) Doppler Accuracy (m/s) 1

Spiral Scan

Issues of Ground Clutter

Ground Clutter Cancellation

Antenna Technology Spherical Antenna Array Feed

Separate transmitter and receiver

Testing Antenna concept 1.5 m prototype

Anti Aliasing Technology

Weight NIS Radar Element Mass (kg) Spacecraft to radar I/F 10 Cables 35 Power distribution unit 5 Digital subsystem LO/IF electronics RF electronics 20 Antenna feed and support structure 100 Antenna reflector and support structure Deployment mechanism 600 200 Radiator and thermal control 90 Nuts/bolts, magnets, misc. H/W Total (kg) 1085

Recommendation Serious consideration should be given to the design and launch of a geostationary active microwave (Doppler radar) observation platform. Continuous Doppler radar coverage of ocean basins frequented by tropical cyclones would : Allow forecasters to monitor the 3D structure of tropical cyclones offer the opportunity to assimilate cloud and mesoscale information into a cloud resolving tropical cyclone prediction model that would lead to incremental improvements in the prediction of tropical cyclone track, intensity and precipitation that could not be matched by any other foreseeable technology.