1. Global Precipitation Measurement – Dual Frequency Precipitation Radar Yong Xiang Teoh EECS823 December 11, 2014 1

2. GPM Mission International partnership in between NASA and JAXA Constellation of satellites including the GPM Core Observatory Core Observatory is the successor to TRMM Launched to the orbit from Tanegashima Space Center, Japan on February 28, 2014 Near global coverage every three hours 2

3. GPM Core Observatory Dimension: 6.5 x 4.9 x 11.6 m Orbit: Circular, non-sun synchronous 65 degrees inclination Altitude: 407km Orbit time: 93 minutes Science Instruments: GPM Microwave Imager (GMI) Dual Frequency Precipitation Radar 3

4. Dual Freq. Precipitation Radar Consists of Ku-PR and Ka-PR Ku-PR is similar to TRMM PR Ka-PR is based upon Ku-PR design with antenna size designed to match the Ku-PR measurement footprint Both use phased array, slotted wave guide antenna Electronically steerable Dual frequencies provide differential reflectivities: Drop size distributions (DSD) More accurate rainfall estimates 4

5. Dual Frequency Measurement 5

6. DPR Specifications Ku-PRKa-PR Frequency13.6GHz35.5GHz Swing angle17deg8.5deg Swath width245km120km Range resolution250m250m/500m Beam Width0.71deg Footprint5km Peak Transmit Power1013W146W PRFVPRF (4206Hz±170Hz)VPRF (4275Hz±100Hz) Pulse width2 x 1.667μs2 x 1.667μs/ 2 x 3.234μs Detection threshold<18 dBZ (<0.5 mm/hr)<12 dBZ (<0.2mm/hr) 6

7. Scan Pattern 7

8. Measured Data A extra-tropical cyclone observed over the northwest Pacific Ocean off the coast of Japan captured by DRP on March 10, 2014 8

9. Measured Data 3D precipitation structures of Typhoon No.11 “HALONG” captured by DPR on August 9, 2014 9

10. References Everett, D.F., Bidwell, S.W., Flaming, G.M., Rykowski, T.B., Stocker, E.F., Braatz, L.E., “Engineering of the global precipitation measurement system”, 2003 Flaming, G.M., “Global Precipitation Measurement Update”, July 25, 2005 Furukawa, K., Kojima, M., Miura, T., Hyakusoku, Y., Iguchi, T., Hanado, H., Nakagawa, K., Okumura, M., “Proto-flight test of the Dual- frequency Precipitation Radar for the Global Precipitation Measurement”, July 24, 2011 Iguchi, T., “Spaceborne Precipitation Radars in TRMM and GPM”, “Global Precipitation Measurement”, http://pmm.nasa.gov/GPMhttp://pmm.nasa.gov/GPM “Global Precipitation Measurement/Dual-frequency Precipitation Radar”, http://global.jaxa.jp/projects/sat/gpm/http://global.jaxa.jp/projects/sat/gpm/ 10