AMSR3 Observation Data Products for Water Cycle Monitoring Now Available
- Supporting numerical weather predictions and fisheries and maritime navigation -
June 30, 2026 (JST)
Japan Aerospace Exploration Agency
The Japan Aerospace Exploration Agency (JAXA) begins providing data (standard products*1) from the "Advanced Microwave Scanning Radiometer 3 (AMSR3)," which contributes to numerical weather predictions and other applications, on June 30, 2026. AMSR3 is one of observation sensors mounted on the Global Observing SATellite for Greenhouse gases and Water cycle "IBUKI GW" (GOSAT-GW). The data are expected to contribute to improving the accuracy of daily weather forecasts and predictions of heavy rainfall and track of tropical cyclones that cause water-related disasters, and will also be useful for identifying productive fishing grounds and supporting efficient maritime navigation.
[Contents of standard products]
Following the completion of the initial calibration and validation verification phase for AMSR3*2, JAXA begins provision of its standard products. The AMSR3 standard products consist of two types: “Brightness Temperature Products” and “Geophysical Parameters Products.”
- Brightness Temperature Products: Fundamental data obtained by converting the intensity of microwaves captured by AMSR3 into temperature.
- Geophysical Parameters Products: Products that provide information on water-related parameters of the Earth, such as precipitation and sea surface temperature, retrieved from the Brightness Temperature Products.
As an example of the products to be provided, Figure 1 shows the precipitation product, which is one of the Geophysical Parameters Products.
White indicates areas of 0 mm/h of precipitation, colored areas indicate the distribution of precipitation, and gray indicates missing data areas.
With AMSR3, precipitation can be estimated over a wider area, including high-latitude regions.
As shown in Figure 1, AMSR2 (left figure) onboard "SHIZUKU" (GCOM-W), launched in 2012, had difficulty estimating precipitation amounts including snowfall*3, resulting in missing areas (gray) remaining mainly in high-latitude regions. By contrast, AMSR3 (right figure) has almost eliminated these missing areas, making it possible to more broadly observe global precipitation (including both rainfall and snowfall). This improved ability to capture precipitation is due to the newly added observation channels in AMSR3.
[Development background and features of AMSR3]
The AMSR series*4, which has approximately 25 years of experience in observing water cycle variability, observes microwaves naturally emitted from the Earth's surface (land and sea), the atmosphere, and other sources, and captures a wide range of information related to the water cycle, including sea surface temperature, precipitation, sea surface wind speed, sea ice concentration, snow depth, and soil moisture.
AMSR3 was developed because its predecessor, AMSR2, was being operated beyond its designed service life of five years. AMSR3 was therefore developed to continue the AMSR2 mission and to respond to new user needs.
In light of this background, AMSR3 adds five new channels sensitive to snow, upper-atmospheric water vapor, and other factors*5. Through these new channels, it is possible to observe the full picture of precipitation (rain and snow) in detail on a global scale, including high-latitude regions, and it is expected to contribute to improving the accuracy of daily weather forecasts and tracks of tropical cyclones made through numerical weather predictions by the Japan Meteorological Agency and meteorological agencies in other countries.
[Examples of product use]
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①
Weather forecasts
AMSR3 products are useful for estimating precipitation amounts, including not only rainfall but also snowfall, and for understanding water vapor distribution. The Brightness Temperature Products derived from the newly added high-frequency channels*6 are planned to be incorporated into the numerical weather models used by the Japan Meteorological Agency and meteorological agencies in other countries for their daily weather forecasts. Preparations for data utilization are currently under way, and it is expected to improve the accuracy of predicting the extent of torrential rainfall and the track and intensity of tropical cyclones.
In addition, these products will also be utilized in JAXA’s Global Satellite Mapping of Precipitation (GSMaP) product, which is used for monitoring water-related disasters such as torrential rain and drought. These data will also play an important role in advancing international cooperation and creating industrial benefits under the priority theme of “Global Water-related Disaster Risk and Resource Management”*7. -
②
Fisheries
Fish have different preferred water temperatures depending on the species. The AMSR series’ sea surface temperature products, which enable continuous observation through clouds, are useful for identifying fishing grounds where fish tend to gather.
With AMSR2 observations to date, it was difficult to accurately determine sea surface temperatures in coastal waters, so it has mainly been used for fisheries in offshore and pelagic areas. With AMSR3, by adding new frequency bands based on user requests, it has become possible to monitor sea surface temperatures and wind speeds over waters closer to the coast than before. This enables observation of continental shelf waters, where large numbers of sardines, mackerel, horse mackerel, and other species inhabit, contributing to efficient fishing-ground searches tailored to each fish species. These data also help reduce the burden on fishers, improve decision-making on fishing operations, and support environmental management in aquaculture. -
③
Ship navigation support
To ensure that ships navigate safely and efficiently, it is important to understand status of sea surface temperatures. For example, around Japan, sea surface temperature information is used to track the Kuroshio, a warm current. Weather satellites such as “Himawari,” which observe the Earth with visible and infrared sensors, may have difficulty capturing conditions at the sea surface when clouds obstruct their view. By contrast, AMSR3 can observe in microwave frequency bands, which are less affected by clouds, enabling it to consistently monitor the Kuroshio Current and helping ships navigate more economically.
Furthermore, for vessels such as the Antarctic research ship “Shirase” that navigate polar regions and ice-covered waters, information on sea ice is indispensable for determining shipping routes. In polar regions, winter brings periods without sunlight and with frequent cloud cover, making it difficult to obtain sufficient information through conventional observation methods. In that respect, the AMSR series products, which can observe sea and ice surface through clouds and repeatedly over a wide area, are extremely important. The products of sea ice concentration and sea ice motion information provided by AMSR3 support shipping route decisions in such environments and contribute to safe navigation in polar regions.
[How to access the provided products]
AMSR3 standard products are provided through JAXA’s Earth observation satellite data providing system(G-Portal). After user registration, anyone can download them free of charge*8. Through the provision of these products, JAXA aims to respond to new user needs and contribute to understanding and forecasting variations in the global water cycle, which is the one of mission objectives of AMSR3, as well as to the social implementation of those results.
End
In light of this release, Ms. Irene Parker, acting Assistant Administrator for NOAA Satellite & Information Service (NESDIS) at our long-time partner, kindly shared the following congratulatory remarks:
“Congratulations to JAXA on successfully completing post-launch verification and validation of AMSR3. This achievement is a testament to the U.S.-Japan collaboration on civil remote sensing for operational meteorology, and NOAA looks forward to a continued partnership on this high impact, mutually beneficial mission.” - Irene Parker
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*1
Standard products
Products are observational data acquired by satellites that have been processed, analyzed, and converted into files for easier use by users. Standard products are provided by JAXA as the basic products necessary to achieve the mission objectives, based on past observation performance and verification results. -
*2
Initial calibration and validation
This refers to the process of evaluating sensor characteristics and the ground processing system for observation data acquired by AMSR3, and making the necessary corrections and adjustments to improve the accuracy of brightness temperatures and geophysical parameters. -
*3
Snowfall
The precipitation product, which is one of the Geophysical Parameters Products, includes rainfall and snowfall. It mainly indicates rainfall in tropical regions and snowfall in high-latitude regions where the surface temperature is 0°C or below. -
*4
AMSR series
The AMSR series includes AMSR-E aboard the U.S. Aqua satellite launched in 2002, AMSR aboard “Midori II” (ADEOS-II), also launched in 2002, and AMSR2 aboard “SHIZUKU” (GCOM-W), launched in 2012. -
*5
Five new channels sensitive to snow, upper-level water vapor, and other factors
Since AMSR2 lacked frequency bands sensitive to snowfall and upper-atmospheric water vapor, its contribution to numerical weather prediction and typhoon track forecasting was limited. The new 165.5, 183.3±7, and 183.3±3 GHz channels among the five new AMSR3 channels overcome this issue. -
*6
Newly added high-frequency channels
These correspond to the three high-frequency channels at 165.5, 183.3±7, and 183.3±3 GHz described in *5. These frequencies are highly sensitive to ice particles drifting within clouds, snow falling to the ground, and water vapor in the middle and upper atmosphere, and can contribute to improving the accuracy of weather forecasting.
For the characteristics of the newly five channels, including these three channels, please refer to Figure 1 in the press release dated September 5, 2025, titled “Early observation results of the Advanced Microwave Scanning Radiometer 3 (AMSR3) onboard the Global Observing SATellite for Greenhouse gases and Water cycle “IBUKI GW” (GOSAT-GW).” -
*7
The priority theme of “Global Water-related Disaster Risk and Resource Management”
Please refer to the web page of Earth-graphy under the priority theme “Global Water-related Disaster Risk and Resource Management.” (Japanese Only) - *8 For examples of how the provided products can be used, please refer here. “Examples of Use（G-Portal）”