The Global Change Observation Mission (GCOM) consists of two polar orbiting satellite observing systems, GCOM-W
(Water) and GCOM-C (Climate), and three generations to achieve global and long-term monitoring of the Earth.
GCOM-W1 is the first satellite of the GCOM-W series and scheduled to be launched in Japanese fiscal year 2011. The
Advanced Microwave Scanning Radiometer-2 (AMSR2) will be the mission instrument of GCOM-W1. AMSR2 will
extend the observation of currently ongoing AMSR-E on EOS Aqua platform. Development of GCOM-W1 and AMSR2
is progressing on schedule. Proto-flight test (PFT) of AMSR2 was completed and delivered to the GCOM-W1 satellite
system. Currently, the GCOM-W1 system is under PFT at Tsukuba Space Center until summer 2011 before shipment to
launch site, Tanegashima Space Center. Development of retrieval algorithms has been also progressing with the
collaboration of the principal investigators. Based on the algorithm comparison results, at-launch standard algorithms
were selected and implemented into the processing system. These algorithms will be validated and updated during the
initial calibration and validation phase. As an instrument calibration activity, a deep space calibration maneuver is
planned during the initial checkout phase, to confirm the consistency of cold sky calibration and intra-scan biases.
Maintaining and expanding the validation sites are also ongoing activities. A flux tower observing instruments will be
introduced into the Murray-Darling basin in Australia, where the validation of other soil moisture instruments (e.g.,
SMOS and SMAP) is planned.
Japan Aerospace Exploration Agency (JAXA) is developing the Advanced Microwave Scanning Radiometer-2
(AMSR2). AMSR2 will be onboard the GCOM-W1 satellite, which is the first satellite of the Japan's Global Change
Observation Mission (GCOM). The second satellite of GCOM will be GCOM-C1, which will carry the Secondgeneration
Global Imager (SGLI). AMSR2 is being developed based on the experience of the AMSR for the EOS
(AMSR-E), which is currently in operation on EOS Aqua satellite more than 6-years. The AMSR2 instrument is a dualpolarized
total power microwave radiometer system with six frequency bands ranging from 7GHz to 89GHz. Major
changes in performance from AMSR-E include the larger antenna diameter of 2.0m for better spatial resolution,
additional 7.3GHz channels for mitigating radio-frequency interference, and improvements of calibration system.
Engineering model of AMSR2 is being manufactured and tested including performance testing of calibration target in
thermal vacuum environment. The GCOM-W1 satellite system finished the preliminary design review before proceeding
to Phase-C in June 2008. AMSR2 will observe various water-related geophysical parameters. We expect a long-term
continuity by leading the AMSR2 to the current AMSR-E observation that has been accumulating six years of data
records. This will contribute to the long-term monitoring of climate variability and daily operational applications.
Current target launch year of GCOM-W1 is the beginning of 2012.
Japan Aerospace Exploration Agency (JAXA) has been proposing the Global Change Observation Mission (GCOM).
GCOM will consist of two series of medium size satellites: GCOM-W (Water) and GCOM-C (Climate). The mission
will take over the Advanced Earth Observing Satellite-II (ADEOS-II or Midori-II). The GCOM-W1 satellite (the first
generation of GCOM-W series) was approved by the Space Activities Commission of Japan to proceed to the
development phase. Current target of launch date is the beginning of 2012. The Advanced Microwave Scanning
Radiometer-2 (AMSR2) is sole mission instrument onboard the GCOM-W1 satellite. Although the simultaneous
observation by a microwave scatterometer and AMSR2 is still desired, installation of the scatterometer is not the case at
least for the GCOM-W1 satellite. AMSR2 is a successor of the AMSR for the EOS (AMSR-E) provided to the NASA
Aqua satellite and AMSR onboard Midori-II with some improvements based on the experiences of AMSR and AMSR-E.
They include an improvement of calibration system and an addition of 7.3 GHz channels to help mitigating radio-frequency
interference issue. The AMSR-E instrument is still providing continuous data records more than 5-years.
Observed brightness temperatures and retrieved geophysical parameters are being widely used for monitoring
environmental changes and for applying to the operational applications such as numerical weather forecasting. We
expect a long-term continuity by leading the GCOM-W/AMSR2 to the AMSR-E observation.
One of the series of satellite for the Global Change Observation Mission (GCOM) is the GCOM-W that will carry the Advanced Microwave Scanning Radiometer (AMSR) follow-on instrument. To keep the continuous observation by the current AMSR for the EOS (AMSR-E) on the Aqua satellite, an earliest launch date is desired. Current proposed launch year is 2010 in Japanese fiscal year. The AMSR-E instrument has been successfully operated for about 4-years and expected to continue providing measurements with high-spatial resolution and in C-band channels that are used to estimate all-weather sea surface temperature and land surface soil moisture. The total dataset period will be over 20-years if the AMSR-E observation can last until the GCOM-W launch. Among the GCOM mission objectives, GCOM-W will focus on the long-term observation of variations in water and energy circulation. In addition, further practical uses including numerical weather forecasting, maritime and meteorological monitoring, and ice applications will be promoted. The AMSR follow-on instrument will be a six-frequency, dual polarized passive microwave radiometer system to observe water-related geophysical parameters. It takes over the basic sensor concept of the AMSR-E instrument with some essential improvements on the calibration system and mitigation of radio-frequency interference (RFI) in C-band channels. Regarding the calibration system, some issues particularly for the warm load target will be investigated and improved based on the AMSR and AMSR-E experiences. Although mitigating the RFI problem is a difficult issue, some preliminary aircraft measurements of anthropogenic radio emissions have performed in Japan and used for assessing the possibilities of sub-band configuration in C-band. Prototyping the several critical components including the above has already started in the last Japanese fiscal year.
Japan Aerospace Exploration Agency (JAXA) is proposing the Global Change Observation Mission (GCOM). The GCOM mission will take over the Advanced Earth Observing Satellite-II (ADEOS-II or Midori-II) mission and develop into long-term monitoring. The GCOM mission will consist of two series of medium size satellites: GCOM-W and GCOM-C (these names are provisional). Three consecutive generations of satellites with one year overlap will result in over 13 years observing period in total. Two observing instruments are proposed for the GCOM-W satellite: the Advanced Microwave Scanning Radiometer (AMSR) follow-on instrument and hopefully the scatterometer for measuring ocean vector winds like SeaWinds onboard Midori-II. To keep the continuous observation by AMSR-E on Aqua, the earliest launch date is desired by science community. Current proposed launch year is 2010. The AMSR follow-on instrument will be a multi frequency, dual polarized passive microwave radiometer that observes water-related geophysical parameters supporting the GCOM concept. To keep the earliest launch date, only minimum but essential modifications from AMSR-E are now being examined. Combination of AMSR follow-on instrument and the scatterometer will provide unique opportunity to generate a synergistic effect of the active and passive microwave measurement. This combination can provide some instrument-level advantages including attenuation and scattering correction for scatterometer. Furthermore, simultaneous measurements of water vapor, SST, precipitation, and sea surface winds are effective for investigating various time-space scale phenomena.
The mission objectives of ADEOS-II (Midori-II) are to improve satellite-based global earth observation system, and to obtain earth observation data for the contribution to better understanding and elucidation of global change mechanism relevant to earth environmental issues. To implement the objectives, five onboard earth observation sensors are selected based on the science requirement primarily focused on the quantitative estimation of geophysical parameters to describe important processes of the earth system such as water and energy cycle, carbon cycle, and changes in polar stratospheric ozone. This paper describes the present status of level-2 products derived from AMSR and GLI observation data after the launch, in the middle of operational observation / calibration and validation phase, as of the beginning of August, 2003 after four months from the beginning of calibration and validation phase on April 15, 2003.
Passive microwave radiometers in the past have demerits of low spatial resolution, and of no lower frequencies. Advanced Microwave Scanning Radiometer (AMSR) and AMSR-E have the largest antenna, and it enables adopting 6 and 10GHz. From those lower frequencies, sea surface temperature (SST) and soil moisture can be retrieved. SST retrieved from AMSR-E has a fine spatial resolution and good accuracy. It shows a potential application, such as tracing oceanic eddies in the Kuroshio Extension region.
The Advanced Microwave Scanning Radiometer (AMSR) is the multi-frequency, passive microwave radiometer on board the Advanced Earth Observing Satellite-II (ADEOS-II), currently called Midori-II. The instrument has eight-frequency channels with dual polarization (except 50-GHz band) covering frequencies between 6.925 and 89.0 GHz. Measurement of 50-GHz channels is the first attempt by this kind of conically scanning microwave radiometers. Basic concept of the instrument including hardware configuration and calibration method is almost the same as that of ASMR for EOS (AMSR-E), the modified version of AMSR. Its swath width of 1,600 km is wider than that of AMSR-E. In parallel with the calibration and data evaluation of AMSR-E instrument, almost identical calibration activities have been made for AMSR instrument. After finished the initial checkout phase, the instrument has been continuously obtaining the data in global basis. Time series of radiometer sensitivities and automatic gain control telemetry indicate the stable instrument performance. For the radiometric calibration, we are now trying to apply the same procedure that is being used for AMSR-E. This paper provides an overview of the instrument characteristics, instrument status, and preliminary results of calibration and data evaluation activities.
The Advanced Microwave Scanning Radiometers (AMSR) are dual-polarized microwave radiometers having channel frequencies ranging from 6.9 GHz to 89 GHz, and were designed to retrieve global information on precipitation, sea surface temperature, oceanic surface winds and integrated cloud water and water vapor, vegetation, sea ice, and snow cover. Two AMSR's have been built by Mitsubishi Electric Corporation for the National Space Development Agency of Japan. The first instrument (AMSR-E) was launched in May 2002 on NASA's Aqua satellite. The second will be launched on the Japanese ADEOS-II satellite. The AMSRs provide the highest spatial resolution yet attained for a civilian spaceborne microwave sensor, with spatial resolutions ranging from 5 km at 89 GHz to 60 km at 6.9 GHz. A distributed array of six (seven for ADEOS-II AMSR) feedhorns are illuminated by a 1.6 m diameter offset parabolic reflector on AMSR-E, and a 2.0 m diameter reflector on AMSR for ADEOS-II. While National Space Development Agency of Japan (NASDA) is responsible for the calibration of both AMSRs' data, for AMSR-E, science software for the retrieval of the various geophysical parameters has been independently developed by NASDA- and NASA-funded researchers. This software has been implemented for routine near-real time processing in both Japan and the United States. A future goal -- within two years -- is the development of joint algorithms for processing data from both AMSRs. Extensive product validation efforts, involving many different countries, are discussed. Initial data from AMSR-E are also presented.
The Airborne Microwave Radiometer (AMR) is a multifrequency, passive microwave radiometer to be installed on an aircraft. Form 1996, the AMR has been used in two spaceborne instrument projects: the Advanced Microwave Scanning Radiometer (AMSR) on the Advanced Earth Observing Satellite- II (ADEOS-II) and the AMSR-E on the EOS Aqua satellite. The major objectives of AMR are to develop retrieval algorithms and to calibrate and validate AMSR and AMSR-E. We recently modified the instrument to improve its stability and usability. The results of a set of test flights show an improved in-flight and interflight stability. We will conduct several AMR underflights to confirm AMSR and AMSR-E on-orbit calibration.