Marehito Kasahara

Status of AMSR2 instrument on GCOM-W1

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, the first satellite of the GCOM-W series, was successfully launched on May 18, 2012 (Japan Standard Time). The Advanced Microwave Scanning Radiometer-2 (AMSR2), which is a successor of AMSR on the Advanced Earth Observing Satellite-II (ADEOS-II) and AMSR for EOS (AMSR-E) on NASA’s Aqua satellite, is a single mission instrument on GCOM-W1. Basic characteristics of AMSR2 is similar to that of AMSR-E to continue the AMSR-E observations, with several enhancements including larger main reflector (2.0 m), additional channels at the C-band frequency band, and improved calibration system. AMSR-E halted its observation on October 4, 2011 due to the increase of antenna rotation torque, which is considered as the typical aging effect. Although all the efforts are being made to resume the AMSR-E observation, early initiation of the AMSR2 observation has been highly desired. After the completion of the orbit injection into the A-Train constellation, AMSR2 started rotating and initiated global observation. During the initial calibration and validation phase, brightness temperatures will be evaluated and characterized through methodologies such as the inter-calibration among similar microwave radiometers including the TRMM Microwave Imager (TMI) and WindSat on Coriolis mission.

Status of AMSR2 on GCOM-W1

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, which is the first satellite of the GCOM-W series, was launched from the Tanegashima Space Center on May 18, 2012 (Japan Standard Time), and moved to the regular observation operation on August 10, 2012 (JST) after the early orbit checkout had been completed. The early initiation of the Advanced Microwave Scanning Radiometer-2 (AMSR2) on GCOM-W1 observation was highly desired since the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) had halted its observation in October 2011 due to the increase of antenna rotation torque. The calibration activity of AMSR2 is going on toward the data release of Level-1 product scheduled in the beginning of 2013. The initial checkout of the ground segment, including systems for receiving, processing, archiving, and distributing the GCOM-W1 data, is also completed successfully. At-launch retrieval algorithms were used for the checkout. These algorithms will be validated and updated through calibration and validation activities. Public data release is scheduled one year after launch for geophysical parameters. Standard products will be available via online, free of charge, from the GCOM-W1 data providing service system. The AMSR-E products are already available from the same system.

Five years of AMSR-E monitoring and successive GCOM-W1/AMSR2 instrument

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.

Status of GCOM-W1/AMSR2 development and science activities

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 Japans 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.

Status of GCOM-W1/AMSR2 development, algorithms, and products

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.

Development of the WAMS-TIR instrument for SPF-II

Wide-Angle Multi-band Sensor - Thermal Infrared (WAMS-TIR), one of the three sensors aboard the station-keeping test airship (SPF-II) for the stratospheric platform project, is a thermal infrared multi-band radiometer designed to observe land surface temperature. WAMS-TIR consists of very wide field-of-view (over 100 deg) optics and an uncooled microbolometer array detector. It has band-pass filters mounted on a rotating wheel to select spectral bands in the range of 7 to 12 microns. A blackbody calibrator is also mounted on the same rotating wheel to calibrate sensor performance in the operation. Results of pre-flight performance tests suggest that WAMS-TIR has the predicted image quality and high radiometric performance. This paper describes the instrument design and the performance tests results of WAMS-TIR.

Development of High Temperature Noise Source (HTS) for Advanced Microwave Scanning Radiometer 2 (AMSR2)

The Advanced Microwave Scanning Radiometer 2 (AMSR2) was developed and provided to Global Change Observation Mission satellite (GCOM-W1) led by Japan Aerospace Exploration Agency (JAXA). AMSR2 observes the global water and energy cycling, such as water vapor, precipitation, sea surface temperature, soil moisture, etc. AMSR2 mounted on GCOM-W1 will be launched by H-IIA Rocket in winter period of FY2011. AMSR2 is now under the spacecraft protoflight test. This paper describes the development and evaluation result of High Temperature Noise Source (HTS), a calibration warm load of AMSR2.

Long-term observations of water and climate by AMSR-E and GCOM-W

The Global Change Observation Mission (GCOM) consists of two satellite observing systems and three generations to achieve global, comprehensive, and long-term Earth monitoring. The first satellite of the GCOM-W (Water) series will be GCOM-W1 with the Advanced Microwave Scanning Radiometer-2 (AMSR2) onboard. AMSR2 is a successor of AMSR on the Advanced Earth Observing Satellite-II (ADEOS-II) and AMSR for EOS (AMSR-E) on NASAs Aqua satellite. Basic performance of AMSR2 will be similar to that of AMSR-E based on the minimum requirement of data continuity of AMSR-E, with several enhancements including larger main reflector (2.0 m), additional channels in C-band receiver, and improved calibration system. Development of the GCOM-W1 satellite and sensor system is going quite smoothly. The satellite system is now in Phase-C and finished the CDR No.1 in July 2009. The CDR No.2 is scheduled in autumn 2009 for reviewing the additional items. The AMSR2 instrument is now in Phase-D and the flight model is being manufactured. Retrieval algorithms are being developed by collaboration with principal investigators for the eight standard products and possible research products. Experiences through the AMSR-E research activities and the data themselves can be directly utilized in the AMSR2 algorithm development. AMSR-E continues its observation nearly seven years. Taking over from the AMSR-E observations to GCOM, we will be able to construct over 20-years data set of unique geophysical parameters including all-weather sea surface temperature and soil moisture content. Current target launch year of GCOM-W1 is in Japanese fiscal year 2011.

Status of the GCOM-W and onboard AMSR follow-on instrument

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.

Five years observations of global water cycle by GCOM-W/AMSR2

The Advanced Microwave Scanning Radiometer 2 (AMSR2) on board the Global Change Observation Mission — Water (GCOM-W or “SHIZUKU”) satellite was launched in May 2012 and will achieve its 5-year designed mission life in May 2017. Major goal of the satellite is to provide continuous observations of global water cycle succeeding role of JAXAs Advanced Microwave Scanning Radiometer for EOS (AMSR-E) on the NASAs Aqua satellite. The GCOM-W satellite is also flying in the A-train orbit to provide synergies among the other A-train satellites, such as Aqua and Cloudsat. During the 5-year mission, we provide eight standard products and two research products to both science and operational communities. Since the satellite and instrument are in healthy conditions, we expect to continue the mission as long as possible to bridge follow-on mission that is currently discussed.