GPM Mission Overview and Status Arthur Y. Hou NASA Goddard Space Flight Center presented by George J. Huffman NASA Goddard Space Flight Center 6th Workshop of the International Precipitation Working Group (IPWG) Sao Jose dos Campos, Brazil, Oct 15-19, 2012

GPM Constellation of Satellites Core Observatory (NASA/JAXA) 2014 Suomi NPP (NASA/NOAA) MetOp B/C (EUMETSAT) Megha-Tropiques (CNES/ISRO) JPSS-1 (NOAA) NOAA 19 (NOAA) DMSP F19/F20 (DOD) GCOM-W1 (JAXA) Next-Generation Unified Global Precipitation Products Using GPM Core Observatory as Reference

Role of the Core Observatory GPM Mission Concept Use coordinated precipitation measurements by a constellation of microwave radiometers to achieve global coverage and sampling through partnerships. Use combined observations from active and passive sensors on the GPM Core satellite to improve the accuracy and consistency of precipitation estimates from all constellation radiometers. Role of the Core Observatory Set a new standard for precipitation measurements from space. Improve GPM constellation sampling by filling the gaps between observations at fixed local times by GPM constellation satellites flying in polar orbits. Provide a radiometric reference to reconcile differences in center frequency, viewing geometry, resolution among constellation radiometer using the GMI as a transfer standard. Provide an a priori observational hydrometeor database consistent with DPR and GMI measurements to unify and improve precipitation estimates from all constellation radiometers.

GPM Core Observatory GPM Microwave Imager (GMI): 10-183 GHz (NASA) Dual-frequency Precipitation Radar (DPR): Ku-Ka bands (JAXA/NICT) Non-Sun-Synchronous orbit at 65o inclination & 407 km 4

DPR Instrument Characteristics Item KuPR at 407 km KaPR at 407 km TRMM PR at 350 km Antenna Type Active Phased Array (128) Frequency 13.597 & 13.603 GHz 35.547 & 35.553 GHz 13.796 & 13.802 GHz Swath Width 245 km 120 km 215 km Horizontal Reso 5 km (at nadir) 4.3 km (at nadir) Tx Pulse Width 1.6 s (x2) 1.6/3.2 s (x2) Range Reso 250 m (1.67 s) 250 m/500 m (1.67/3.34 s) 250m Observation Range 18 km to -5 km (mirror image around nadir) 18 km to -3 km (mirror image around nadir) 15km to -5km (mirror image at nadir) PRF VPRF (4206 Hz170 Hz) VPRF (4275 Hz100 Hz) Fixed PRF (2776Hz) Sampling Num 104～112 108～112 64 Tx Peak Power > 1013 W > 146 W > 500 W Min Detect Ze (Rainfall Rate) < 18 dBZ ( < 0.5 mm/hr ) < 12 dBZ (500m res) ( < 0.2 mm/hr ) ( < 0.7 mm/hr ) Measure Accuracy within ±1 dB Data Rate < 112 Kbps < 78 Kbps < 93.5 Kbps Mass < 365 kg < 300 kg < 465 kg Power Consumption < 383 W < 297 W < 250 W Size 2.4×2.4×0.6 m 1.44 ×1.07×0.7 m 2.2×2.2×0.6 m * Minimum detectable rainfall rate is defined by Ze=200 R1.6 (TRMM/PR: Ze=372.4 R1.54 )

Expected Beam Efficiency (%) Expected Cal. Uncertainty (K) GMI Instrument Characteristics Frequency NEDT Req. (K) Expected* NEDT (K) Expected Beam Efficiency (%) Expected Cal. Uncertainty (K) Resolution (km) 10.65 GHz (V & H) 0.96 92.1 1.04 19.4 x 32.2 18.7 0.84 0.82 93.3 1.08 11.2 x 18.3 23.8 (V) 1.05 94.3 1.26 9.2 x 15.0 36.5 0.65 0.56 98.5 1.20 8.6 x 14.4 89.0 0.57 0.40 95.6 1.19 4.4 x 7.3 165.5 1.5 0.81 91.9 183.31±3 0.87 91.7 183.31±7 Data Rate: ~30 kbps Power: 162 Watts Mass: 166 kg * Analysis data as of Sept. 2010 Deployed Size: 1.4 m x 1.5 m x 3.5 m Antenna Size: 1.2 m Swath: 885 km Resolution and swath for GMI on Core

Core Observatory Integration & Testing at NASA/GSFC

Prototype GPM Radar-Enhanced Radiometer Retrieval Unified radiometer rainfall retrieval using a common a priori hydrometeor database consistent with combined DPR+GMI measurements. Proof-of-concept demonstration using TRMM PR and TMI: Outer Swath: TMI rainfall retrieval using an a-priori cloud database derived from PR reflectivity and TMI radiances within the inner swath. Inner Swath: PR rainfall retrieval (at different spatial resolution) Kummerow et al.

Science Status GPM algorithm delivery on schedule for early 2014 launch: Baseline DPR and GMI codes delivered to NASA and JAXA data processing systems in 2011. At-launch codes on schedule for delivery in Nov. 2012 for Operational Acceptance Testing in 2013. Field campaigns supporting pre-launch algorithm development: Pre-CHUVA with Brazil on warm rain retrieval over land in Alcântara, 3-24 March 2010. Light Precipitation Validation Experiment (LPVEx) with Finnish Met. Institute: CloudSat-GPM light rain in shallow melting layer situations in Helsinki, Finland, 15 Sept - 20 Oct 2010. Mid-Latitude Continental Convective Clouds Experiment (MC3E): NASA-DOE field campaign in central Oklahoma, 22 Apr 22 – 6 June 2011. GPM Cold-season Precipitation Experiment (GCPEX): Joint campaign with Environment Canada on snowfall retrieval in Ontario, Canada, 17 Jan – 29 Feb 2012. GPM participation in HyMeX SOP in Sept-Oct 2012. 3 more campaigns planned for 2013-2016. Italy will host the 6th GPM International Ground Validation Workshop in Rome, Nov 2013. Pre-CHUVA (2010) MC3E (2011) NASA-EC GCPEX (2012) LPVEx (2010) (satellite simulator) (in situ microphysics)

Summary Advanced active/passive sensor capabilities GPM is an international satellite mission that will unify and advance precipitation measurements from a constellation of microwave sensors for research and application Summary Advanced active/passive sensor capabilities Higher sensitivity to light rain and solid precipitation than TRMM instruments Insights into precipitation physics with quantitative estimates of PSD parameters Next-generation unified global precipitation data products Inter-calibrated radiometric data from a constellation of MW sensors Unified precipitation retrieval using a common hydrometeor database consistent with combined active/passive sensor measurements Near real-time data for operational use and societal applications Core Observatory status: Observatory integration is near completion and preparation for environmental testing in progress Launch Readiness Date: Early 2014 Science status: GPM algorithm delivery on schedule NASA conducting joint field campaigns with international and domestic partners supporting pre-launch algorithm development and post-launch product evaluation NASA Precipitation Science Team currently has 21 International Pr. Investigators from 13 nations CNR/ISAC of Italy will host the 6th International GPM GV Workshop in Rome, Nov 2013.

http://gpm.nasa.gov