1. G O D D A R D S P A C E F L I G H T C E N T E R 1 GPM Constellation Reconfiguration and Mission Status Arthur Y. Hou NASA Goddard Space Flight Center arthur.y.hou@nasa.gov IPWG 3rd Workshop, October 23-27, 2006 Melbourne, Australia

2. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 2 GPM Core Spacecraft carries a dual-frequency radar & a multi-frequency radiometer to providemeasurements of 3-D precipitation structuresand microphysical properties to serve as aprecipitation physics observatory for improved understanding of precipitation processes andretrieval algorithms. GPM Core Spacecraft is in a 65 o -inclined orbit to provide coincident measurements with partnersatellites, enabling the Core radar/radiometer to serve as a reference standard to obtain uniformly calibrated global precipitation measurementsfrom a heterogeneous constellation of dedicatedand operational passive microwave radiometers. GMI KuPR KaPR GPM is an international satellite mission to unify and advance global precipitation measurements GPM advances over current capabilities:

3. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 3 GPM originally conceived as a satellite mission that provides precipitation measurements around the globe approximately every 3 hours by conically-scanning radiometers 3 Hour Coverage by GPM Core and 7 Constellation Radiometers comprising dedicated and operational satellites: GPM Core, F18, F19, GCOM-W, Megha-Tropiques, NASA-1, Partner-1, Partner-2

4. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 4 Recent progress in sensor capabilities and retrieval algorithms - notably proven capability of AMSU-B high-frequency water-vapor channels improved quality of AMSU-B precipitation retrievals has enabled GPM to evolve during its formation phase Milestones: Approval of GMI high-frequency capabilities in 2005 Reconfiguration of the baseline GPM constellation to include crossing-track microwave sounders over land NASA constellation satellite in a low inclination orbit to improve near-realtime hurricane monitoring & prediction

5. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 5 Surface Rain Retrievals from Passive Microwave Sensors Compared with TRMM PR Over U.S. Normalized RMS errors of TMI, AMSR-E, F13, F14, & F15 surface rain retrievalswith respect to ground measurements over U.S., and corresponding errors forAMSU-B (15, 16, 17) and TRMM PR 0.25 o instantaneous retrievals within hourlywindows against continuoussurface radar & gaugemeasurements for JJA 2005 Sounder retrievals withHF water vapor channelsare closer to PR thanC-S imagers without HFbetween 1-10 mm/h In GPM era most C-S imagers & X-T sounders will have HF channels RMS errorsdue totemporalmismatcheswithin 1hobservationwindow forperfectretrievals Lin & Hou (2006)

6. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 6 0.25 o instantaneous retrievals within hourly windows (Jan-Dec 2005) RMS errors due to temporal mismatches within 1h observation window for perfect retrievals Over U.S. (South of 35N) Over Tropical Land (35N-35S) TRMM PR Lin & Hou (2006) Surface Rain Retrievals from Passive Microwave Sensors Over Land

7. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 7 Average Revisit Times by Passive Microwave Sensors in GPM Era With addition of MetOp-B, NPP, NOAA-19, & NPOESS-C1 over land GPM Core, NASA-1(40 o ), F18, F19 GCOM-W, Megha-Tropiques 6 Conically-Scanning Imagers ( < 3h over 86% of globe) Hour 6 C-S Imagers Plus 4 Cross-track Sounders (Over land) ( < 3h over 92% of globe) Lin & Hou (2006)

8. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 8 Constellation microwave sensor channel coverage Mean Spatial Resolution (km) Different center frequencies, viewing geometry, and spatial resolution must be reconciled Channel6 GHz 10 GHz 19 GHz 23 GHz 31/36 GHz 50-60 GHz 89/91 GHz150/166 GHz 183/190 GHz AMSR-E6.925 V/H 10.65 V/H 18.7 V/H 23.8 V/H 36.5 V/H 89.0 V/H GMI10.65 V/H18.70 V/H23.80 V36.50 V/H89.0 V/H165.5 V/H183.31 V MADRAS18.7 V/H23.8 V36.5 V/H89.0 V/H157 V/H SSMIS19.35 V/H22.235 V37.0 V/H50.3-63.28 V/H91.65 V/H150 H183.31H MHS89 V157 V183.311 H 190.311 V ATMS23.831.450.3-57.2987-91164-167183.31 V – Vertical PolarizationH – Horizontal Polarization Channel6 GHz10 GHz19 GHz 23 GHz 31/36 GHz 50-60 GHz 89/91 GHz 150/166 GHz 183 GHz AMSR-E56382124125 GMI26151211666 MADRAS40 106 SSMIS59 362214 MHS17 ATMS74 3216 Passive Microwave Sensor (PMW) Characteristics in GPM Era

9. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 9 GPM provides a consistent framework to unify a heterogeneous constellation of PMW sensors (both C-S imagers and X-T sounders) Level 1B T B Bias at non-rainy pixels Sensor Channel (GHz) Retrieved - Sensor T B (K) Intercalibrated Level 1C T B w.r.t. TMI Sensor Channel (GHz) CourtesyC. Kummerow Coincidentsensor T B calibrated tosimulated TMI T B Using DPR+GMI on GPM Core to calibrate coincident T B ’s rainy and non-rainy pixels L1C homogenizes existing L1B for precipitation retrieval without replacing official L1B products An open community effort: http://mrain.atmos.colostate.edu/LEVEL1C/ By making combined use of DPR & GMI on GPM Core Spacecraft to provide - a uniform calibration of brightness temperature measurements and - a common cloud/hydrometeor database for precipitation retrievals

10. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 10 GPM Mission: Improve understanding of precipitation physics Unify a heterogeneous constellation of passive microwave sensors to provide accurate and timely global precipitation measurements for research & applications GPM Core Spacecraft Increased sensitivity for light rain and snow detection Better overall measurement accuracy Uniform calibration of brightness temperatures of Constellation sensors Detailed microphysical information and a common cloud database for rain & snow retrievals from Core & Constellation sensors NASA constellation in a low-inclination orbit Improved near-real time hurricane monitoring and prediction GPM CoreNASA-40 o GCOM-WMegha-TropiquesNOAA-19NPPMetOp-BNPOESS-C1

11. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 11 GPM Ground Validation for Improving Satellite Simulators, Retrieval Algorithms, & Hydrological Applications Statistical validation sites for direct assessment of GPM satellite surface precipitation products: –Co-located with existing or upgraded national network (NEXRAD etc.) and dense gauge networks to identify and resolve significant discrepancies between the national network and satellite estimates –Leveraging off national networks of partnership countries and international scientific collaboration for regional and global assessments Precipitation process sites for improving understanding and modeling of precipitation physics in physical and radiance spaces for satellite retrieval algorithm refinements: –Continental tropical, mid- and high-latitude sites (including orographic/coastal sites and targeted sites for resolving discrepancies between satellite algorithms) –Oceanic tropical and mid-latitude sites –Aircraft measurements Integrated hydrological sites for improving hydrological applications: –Co-located with existing watersheds maintained by other US agencies and international research programs to use hydrological basins as an integrated measure of the quality of precipitation products International GPM GV partnership opportunities

12. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 12 GPM Participation in the Canadian CloudSat/Calipso Validation Program Winter 2006-2007 1.GPM hardware contributions: an Advanced Multi-frequency (Ka-Ku-W) radar (UMass) a 2D video disdrometer (CSU) GSFC Parsvels for measuring hydrometeor numbers, sizes (maximum width), type, and fall speeds 2. Collection of data sets for development of GPM snowfall detection and estimation algorithms Develop models that convert microphysical properties (snow size, shape distributions, density, ice-air-water ratio) to radiative properties (asymmetry factor, absorption- scattering-backscatter coefficients) Relate radiative properties to microwave radiances and radar reflectivities observed by GPM instruments Combine satellite, aircraft and ground measurements for GPM GMI and DPR algorithm validation Support Cloud-Resolving Model (CRM) microphysics validation in cold-region simulations Joint CloudSat/CALIPSO/GPM Field Campaign

13. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 13 GPM Mission Status NASA and JAXA have signed an agreement to jointly formulate the GPM mission with the following assumptions: –JAXA to provide a Dual-frequency Precipitation Radar (DPR) for the GPM “Core” spacecraft and launch services for the Core spacecraft KuPR and KaPR engineering model under development & testing –NASA to provide two GPM Microwave Imager (GMI)’s, the Core spacecraft, a constellation spacecraft & associated launch services GMI in development by Ball Aerospace Technology Corporation Joint NASA and industry development of Core Spacecraft underway –Selection of a new NASA/Precipitation Missions Science Team (November 2006) GPM Core spacecraft launch circa 2013 Constellation partnership development –Partnerships in formulation: JAXA, NOAA, DoD –Partnerships under discussion: AEB (Brazil) –Future opportunities: ISRO(India)/CNES(France), ESA, EUMETSAT GPM Planning Workshops –6th GPM International Planning Meeting to be held 6-8 November 2005 in Annapolis, MD, USA. –2nd GPM International Ground Validation Workshop held in September 2005 in Taipei, Taiwan. 3rd GV Workshop is under planning for 2007.

14. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 14 Recent National Research Council Recommendations “The (NASA) Global Precipitation Measurement (GPM)mission should be launched without further delays.” - Earth Science and Applications from Space : Urgent Needs and Opportunities to Serve the Nation, National Academies Press, Washington, DC, 2005 “NOAA takes over the operation of the GPM Core satellite fromNASA five years after launch.”“Develop a GPM follow-on NOAA program... as U.S. componentsof a continuing and evolving international constellation ofsatellites within the WMO... for satellite-based globalprecipitation measurements.” – Report of NRC/BASC Committee on the Future of Precipitation Missions, September, 2006

15. Arthur Hou, October 23, 2006 G O D D A R D S P A C E F L I G H T C E N T E R 15 The GPM Mission will unify and advance global precipitation measurements by providing advanced microwave sensors (DPR & GMI): a consistent framework for inter-satellite calibration science teams for algorithm development, ground validation, and improved use of precipitation data in research & applications Summary The success of GPM will rely on the continued support and advocacy of the community such as IPWG!