Operation of the Advanced Microwave Scanning
Radiometer-EOS (AMSR-E) onboard the US Earth Observing
Satellite “Aqua” completed
December 7, 2015 (JST)
National Research and Development Agency
Japan Aerospace Exploration Agency (JAXA)
The Japan Aerospace Exploration Agency (JAXA) has completed operation of the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) at around 2:30 p.m. on December 4, 2015 (Japan Standard Time, JST).
The AMSR-E has been operated for over nine years as an onboard device installed in the US Earth Observing Satellite (EOS) “Aqua”, after its launch on May 4, 2002. At 3:58 p.m. on October 4, 2011 (JST), the AMSR-E reached its limit to maintain the antenna rotation speed necessary for regular observations (40 rotations per minute), and the radiometer automatically halted its observation and rotation. After observation by the AMSR-E was suspended, JAXA prepared a recovery plan with NASA engineers, and the AMSR-E restarted its observation in slow rotation mode (2 rotations per minute) on December 4, 2012. Although the AMSR-E observation data in slow rotation mode limited to observe sparse areas, it was used for cross-calibration with the AMSR2 (successor of the AMSR-E) onboard the Global Change Observation Mission-Water “SHIZUKU” (GCOM-W) since its launch on May 18, 2012, in order to produce and provide a consistent and long-term dataset between the AMSR-E and AMSR2 by correcting their differences in sensor properties.
However, the AMSR-E reached its limit to maintain the antenna rotation speed necessary for slow rotation mode (2 rotations per minute,) and it automatically halted its observation and rotation at around 2:30 p.m. on December 4, 2015 (JST). As December marks just three years of simultaneous AMSR-E and AMSR2 operation, and because we obtained sufficient data necessary for cross-calibration, we decided to complete operation of the AMSR-E at this time.
At present, the AMSR2 has been operating as the successor of the AMSR-E in the same orbit. The AMSR2 continues the long-term, high-resolution observation of global water cycle variation by the AMSR-E and related operational utilization, which are new fields exploited by the AMSR-E (see the Appendix for more details). Moreover, the AMSR2 contributes on an ongoing basis to both fields of practical application and water cycle/and climate variation research.
The AMSR-E is a microwave scanning radiometer featuring the world's highest level of performance, and has continued its observation for nine years, five months as the only passive microwave imager in the afternoon orbit. It can observe global-scale water, including ocean ice, surface temperatures, vapors, precipitation and soil water, regardless of weather conditions and whether day or night, by measuring faint radio waves emitted from Earth. Its observation and utilization in various practical applications and research fields are succeeded by the AMSR2 (launched in May 2012).
(1) Contributing to practical fields
- The AMSR-E contributed to improving the accuracy of weather forecasts by the Japan Meteorological Agency as its data was used for numerical weather predictions and for determining the center of a typhoon. The data was also used in the production of daily global sea surface temperature dataset to monitor oceanic conditions on a near-real-time and operational basis.
- The AMSR-E was also helpful for more efficient fishing boat operations as the fishing industry information service center and other organizations used the data for compiling information on ocean conditions for fishing.
- The AMSR-E also contributed to monitoring of the Sea of Okhotsk by the Japan Coast Guard and the editing of a report on overseas food demand based on a study of global drought conditions by the Ministry of Agriculture, Forestry and Fisheries.
- In addition, the AMSR-E was operationally used in numerical weather predictions and the monitoring of meteorological and oceanic phenomena by such organizations as the US National Oceanic and Atmospheric Administration (NOAA), the European Centre for Medium-range Weather Forecasts (ECMWF), and the Canadian Ice Service (CIS).
(2) Contributing to water cycle and climate change research
- Through long-term continuous observations of Arctic sea ice, the AMSR-E proved very helpful in understanding the impact of global warming by clarifying the smallest Arctic sea ice area in observation history (at that time) in the summer of 2007, as well as the area’s second largest decrease in observation history (at that time) in the summer of 2011.
- Analysis results regarding the shrinkage of the Arctic sea ice extent observed by passive microwave imagers including the AMSR-E were referenced in the Fifth Assessment Report (AR5) prepared by the Intergovernmental Panel on Climate Change (IPCC) Working Group I.
- Along with data observed by other satellites, the radiometer's data contributed significantly to the production of global precipitation maps, such as JAXA’s Global Satellite Mapping of Precipitation (GSMaP,) NASA’s TRMM and TRMM Multi-satellite Precipitation Analysis (TMPA,) and NOAA’s CPC Morphing Technique (CMORPH,) as well as a dataset on global high-resolution sea surface temperature.
- The data also proved very useful for international climate change research.