Status of the GCOM mission and the important role of scatterometerHaruhisa Shimoda1, 2, Keiji Imaoka1, and Akira Shibata1

1 Japan Aerospace Exploration Agency2 Tokay University Research and Information Center

Satellite Measurements of Ocean Vector Winds:Present Capabilities and Future Trends

Miami, FLFebruary 7-9, 2005

OverviewAfter the Midori-II loss on October 2003, JAXA and science teams have been discussing desired follow-up activity of Midori-II.Global Change Observation Mission (GCOM) is being proposed to contribute climate change portion of the GEOSS framework.Combination of AMSR and SeaWinds-type scatterometer is highly desired for GCOM-W.JAXA is proposing NASA to provide scatterometer for GCOM-W satellite.

Note: This chart includes NOT authorized plan

A plan of advanced low Earth orbit satellitesTo develop advanced low Earth orbit satellitesto aim cutting edge system and mutual complementary system to the operational system such as WWW, NPOESSTo develop and operate an Earth Observation Network for GEOSS

Sea surface wind vectorAMSR F/O, Scatterometer (GCOM-W)SSTAMSR F/O (GCOM-W)Cloud structureCloud Profiling Radar (EarthCARE)AerosolGLI F/O (GCOM-C)CO2 concentrationGreenhouse Gas Observation Sensor (GOSAT)PrecipitationDual-frequency Precipitation Radar (GPM)Disaster monitoringSAR/disaster monitoring satellites, Optical Sensor/Geo-stationary EO satellite

Earth Observation Summit, GEOSS, and GCOMThe 2nd Earth Observation SummitHeld in Tokyo on April, 2004The Framework for a 10-Year Implementation PlanThe Communique of the 2nd Earth Observation Summit

The 10-Year Implementation PlanGives guidance for establishing new Global Earth Observation Systems of Systems (GEOSS) by strengthen existing observation systems, establishing successor international mechanism.JAXA will propose a series of satellites for establishing GEOSS mainly focused on observations of climate change for loss of ADEOS-II, in addition to ALOS for disaster, GPM for water cycle, GOSAT for carbon cycle.

Global Change Observation MissionGCOM consists of 2 satellite series:Sea surface observation mission, so called GCOM-W, will have AMSR F/O and a scatterometer.Atmospheric and terrestrial observation mission, so called GCOM-C, will have GLI F/O.Each series will have 3 satellites with 5 years mission: totally covers 13 years (1-year overlap between consecutive satellites).Middle size common bus system to improve reliability.Being developed for GOSAT.Common basic design with specific modules to fit each mission and improve the basic design.Basically 1 mission (and/or sensor) as risk management.

GCOM satellitesGCOM-W satelliteSensorsAdvanced Microwave Scanning Radiometer (AMSR) F/OScatterometer (under discussion)Sun-Synchronous polar orbit, orbit height: 800km, swath 1400km, LTN: 13:30(tentative)2009 first launch is proposedGCOM-C satelliteSensorSecond generation Global Imager (SGLI)Sun-Synchronous polar orbit, orbit height: 1000km, swath 1200km, LTN: 13:30 (tentative)2010 first launch is proposed

AMSR on Midori-IINon-deployable, offset parabolic antenna with effective aperture size of 2.0 m.Total power microwave radiometers.High Temperature noise Source (HTS) and Cold Sky Mirror (CSM) for onboard two-point calibration.Two feed horns for 89GHz to keep enough spatial sampling in along track direction.

AMSR Sea surface temperature

Oceanic geophysical parameters by AMSRTotal precipitable waterCloud liquid waterSea surface wind speedPrecipitationGlobal Monthly Mean in April 2003

GCOM satellitesGCOM-W satelliteSensorsAdvanced Microwave Scanning Radiometer (AMSR) F/OScatterometer (under discussion)Sun-Synchronous polar orbit, orbit height: 800km, swath 1400km, LTN: 13:302009 first launch is proposedGCOM-C satelliteSensorSecond generation Global Imager (SGLI)Sun-Synchronous polar orbit, orbit height: 1000km, swath 1200km, LTN: 13:302010 first launch is proposed

250m oceanGLI 250m RGB:22/21/202003.5.26

Continuous observation by AMSRContinue unique AMSR observation (high-res and global) and construct long-term dataset.Reliable long-term time series of SST, sea surface winds, water vapor, precipitation, and ocean flux to contribute to the understanding, monitoring, and forecast of climate change.Operational benefits include continuous measurement of cloud-through SST, frequent and quantitative measurements of storms to maintain precipitation forecast accuracy.Overlapping period of consecutive sensors aids cross-calibration to establish stable long-term records.Contribution to the GPM constellation.

Basic requirements for AMSR F/OMinimum modifications from AMSR on ADEOS-II to reduce risks/cost and keep the earliest launch date.However, several essential improvements will be indispensable.Improvement of calibration system including warm load calibration target.Consideration to C-band radio frequency interference (RFI).Combination with SeaWinds-type scatterometer is highly desired.

Basic requirements for AMSR F/OAntenna : 2.0m, offset parabolic antennaChannel setsIdentical to AMSR-E (no O2 band channels)6.925(TBD), 10.65, 18.7, 23.8, 36.5, 89.0GHzDual polarizationCalibrationImprovements of hot load etc.Enhance pre-launch calibration testingOrbitAfternoon orbit with 700~800km altitudeMission life5 years goal

On-going discussionRFI mitigation at C-bandConsidering appropriate center frequency around 6.9GHz (hardware mitigation may be difficult due to tight schedule).Polarimetric channel for 36.5GHzOnly U or V stokes for 36.5GHz due to the limitation of feed and receiver packaging (difficult for 18.7GHz).Redundancy of important channelsLessons learned from 89GHz problem of AMSR-E.36.5GHz V/H channels are used in many retrievals.Relationship to GCOM-C/SGLI orbit

SeaWinds/AMSR combinationScatterometer/Radiometer combination since SeaSat.Unique combination still in NPOESS+METOP era.AdvantagesSeaWinds : Rain flagging and attenuation/scattering correction.AMSR : Improvement of Tb model as a function of wind vector.Application to Meteorology/Physical OceanographyOcean surface heat flux : needs simultaneous observation.Simultaneous measurements of water vapor, SST, precipitation, and sea surface winds are effective for investigating various time-space scale phenomenon (MJO, typhoon, monsoon, ENSO, water-energy cycle, ocean circulation in surface mixed layer)Synergism of active/passive measurement in other research areas are also expected.Ice drift monitoring, detection of snow and ice melting, land surface sensing including vegetation and soil moisture.

Provided by Dr. Frank Wentz of Remote Sensing Systems

Wind vector dependence of AMSR brightness temperatures by using AMSR and SeaWinds. Horizontal axis indicates relative wind direction by SeaWinds (0 degree corresponds to up-wind case), vertical axis indicates deviations of AMSR 37GHz Tb from that under calm ocean condition. Data of September 2003 were used. Provided by Dr. M. Konda of Kyoto University.SST: 25-30CPW : 36-38mmCLW:0.04-0.08Kg/m2

Simultaneous measurementsSnapshots of AMSR level2 standard product of (a) the latent heat flux, (b) the SST, (c) wind speed, and (d) the water vapor pressure in the East China Sea on December 20, 2003. Wind direction observed by SeaWinds scatterometer on QuikSCAT is superimposed by black arrows.(a)(b)(d)(c) Provided by Dr. M. Konda of Kyoto University.

Continuity of ScatterometerOcean wind vector measurement continues for over 10-years since ERS-1/AMI launch in 1991.METOP/ASCAT will be available in near future. Combination with GCOM-W scatterometer will increase time resolution (or coverage).Wind vector retrieval by polarimetric radiometer is epoch making, but may need validation phase with simultaneous observation by scatterometer.Scatterometer data are valuable in operational use.

SummaryGCOM is being proposed as the follow-on mission of Midori-II.Combination of AMSR and SeaWinds-type scatterometer is highly desired for GCOM-W satellite.JAXA is proposing NASA to provide scatterometer for GCOM-W satellite.

Backup Slides

AMSR Follow-on Sensor TeamIn alphabetic order (FY15 members) :

Kazumasa Aonashi (Meteorological Research Institute)Kohei Cho (Tokai University)Naoto Ebuchi (Institute of Low Temperature Science, Hokkaido University)Yasuhiro Fujimoto (Fuji. Tech)Keiji Imaoka (Earth Observation Research and application Center, JAXA)Toshio Koike (The University of Tokyo)Harunobu Masuko (National Institute of Information and Communications Technology)Masashige Nakayama (Earth Observation Research and application Center, JAXA)Tetsuo Nakazawa (Meteorological Research Institute)Fumihiko Nishio (Chiba University)Katsuya Saito (Japan Fisheries Information Service Center)Akira Shibata (Earth Observation Research and application Center, JAXA)Shuji Shimizu (Earth Observation Research and application Center, JAXA)Haruhisa Shimoda (Tokai University)Nobuhiro Takahashi (National Institute of Information and Communications Technology)Yoshiaki Takeuchi (Japan Meteorological Agency)

Necessity of finer spatial resolutionParticularly for lower frequency channels.Spatial resolution of SST by 6.9GHz to resolve mesoscale eddies (10-100km) that affect maritime variation and are important for fisheries. In fishery applications, ships can move about 1-100km during a day. Goal of microwave radiometer would be 10km, but practical target is 25km.10GHz Tb are necessary to retrieve heavy precipitation. Finer resolution is desired comparing to the grid size of near future global model (20km).Resolving smaller scale phenomena is needed for land use by using 6.9GHz Tb and retrieved soil moisture.Decrease errors due to coarse resolution (e.g., beam filling proglem).Promote cross-utilization with optical and infrared instruments by narrowing spatial resolution discrepancy.

SST from GLI and AMSRDetectable size of oceanic eddies are approximately 50km by AMSR observation. Ideal goal for AMSR spatial resolution is 10km, but practical requirement is 25km. This resolution will resolve finer scale eddies (e.g., areas A and B) and provide useful information to fishery.50kmAB

JAXA satellite project plan including not yet approved future projectsGCOM is a follow-on mission of Midori-II and focuses on contributing the GEOSS activities from climate change point of view.Cloud-through measurement of SST is one of the advantages of the AMSR measurement.As well known, oceanic geophysical parameters that can be retrieved from AMSR data include water vapor, cloud liquid, sea surface temperature, sea surface wind speed, and precipitation.GCOM-C/SGLI will focus on 250m observation of land and coastal regions to provide useful information to anthropogenic changes. This is an example image of GLI/Midori-II showing the 250m capability for coastal ocean color.Simultaneous measurement of oceanic parameters will provide useful information for investigating ocean-atmosphere interaction including heat flux determination.