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. HouNASA Goddard Space Flight Center

arthur.y.hou@nasa.gov

IPWG 3rd Workshop, October 23-27, 2006 Melbourne, Australia

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 provide measurements of 3-D precipitation structures and microphysical properties to serve as a precipitation physics observatory for improved understanding of precipitation processes and retrieval algorithms.

• GPM Core Spacecraft is in a 65o -inclined orbit to provide coincident measurements with partner satellites, enabling the Core radar/radiometer to serve as a reference standard to obtain uniformly calibrated global precipitation measurements from a heterogeneous constellation of dedicated and 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:

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

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

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 retrievals with respect to ground measurements over U.S., and corresponding errors for AMSU-B (15, 16, 17) and TRMM PR

0.25o instantaneous retrievals within hourly windows against continuous surface radar & gauge measurements for JJA 2005

Sounder retrievals with HF water vapor channels are closer to PR than C-S imagers without HF between 1-10 mm/h

In GPM era most C-S imagers & X-T sounders will have HF channels

RMS errors due to temporal mismatches within 1h observation window for perfect retrievals Lin & Hou

(2006)

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

0.25o 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

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(40o ), 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)

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

Channel 6 GHz

10 GHz

19 GHz

23 GHz

31/36 GHz

50-60 GHz

89/91 GHz 150/166 GHz

183/190 GHz

AMSR-E 6.925V/H

10.65V/H

18.7V/H

23.8V/H

36.5V/H

89.0 V/H

GMI 10.65 V/H 18.70 V/H 23.80 V 36.50 V/H 89.0 V/H 165.5 V/H 183.31 V

MADRAS 18.7 V/H 23.8 V 36.5 V/H 89.0 V/H 157 V/H

SSMIS 19.35 V/H 22.235 V 37.0 V/H 50.3-63.28 V/H 91.65 V/H 150 H 183.31H

MHS 89 V 157 V 183.311 H 190.311 V

ATMS 23.8 31.4 50.3-57.29 87-91 164-167 183.31

V – Vertical Polarization H – Horizontal Polarization

Channel 6 GHz 10 GHz 19 GHz

23 GHz

31/36 GHz

50-60 GHz

89/91 GHz

150/166 GHz

183 GHz

AMSR-E 56 38 21 24 12 5

GMI 26 15 12 11 6 6 6

MADRAS 40 40 40 10 6

SSMIS 59 59 36 22 14 14 14

MHS 17 17 17

ATMS 74 74 32 16 16 16

Passive Microwave Sensor (PMW) Characteristics in GPM Era

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 TB Bias at non-rainy pixels

Sensor Channel (GHz)

Ret

riev

ed -

Sen

sor

TB (

K) Intercalibrated Level 1C TB w.r.t. TMI

Sensor Channel (GHz)

Courtesy C. Kummerow

Coincident sensor T B calibrated to simulated 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

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-40o

GCOM-WMegha-TropiquesNOAA-19NPPMetOp-BNPOESS-C1

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

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 ProgramWinter 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

1. Develop models that convert microphysical properties (snow size, shape distributions, density, ice-air-water ratio) to radiative properties (asymmetry factor, absorption-scattering-backscatter coefficients)

2. Relate radiative properties to microwave radiances and radar reflectivities observed by GPM instruments

3. Combine satellite, aircraft and ground measurements for GPM GMI and DPR algorithm validation

4. Support Cloud-Resolving Model (CRM) microphysics validation in cold-region simulations

Joint CloudSat/CALIPSO/GPM Field Campaign

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.

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 from NASA five years after launch.”

“Develop a GPM follow-on NOAA program... as U.S. components of a continuing and evolving international constellation of satellites within the WMO ... for satellite-based global precipitation measurements.”

– Report of NRC/BASC Committee on the Future of Precipitation Missions, September, 2006

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!