Satellites and Spacecraft Global Change Observation Mission - Water "SHIZUKU" (GCOM-W)

In Operation

Project Topics

Nov. 2, 2015 Updated

Release of the JAXA Realtime Rainfall Watch

Release of the JAXA Realtime Rainfall Watch

Earth Observation Research Center (EORC) of Japan Aerospace Exploration Agency (JAXA) has developed GSMaP realtime version (GSMaP_NOW) providing rainfall information of current hour, and released those information through a new webpage “JAXA Realtime Rainfall Watch”. While GSMaP near-real-time version (GSMaP_NRT) is provided with 4-hour data latency, which consists of 3-hour for data gathering and 1-hour for processing, GSMaP_NOW is provided in quasi-realtime and updated every half-hour. For ...

Press Release


About Global Change Observation Mission - Water

Observing All Environmental Changes on Earth for Present and Future Generations

The "Global Change Observation Mission" (GCOM) aims to construct, use, and verify systems that enable continuous global-scale observations (for 10 to 15 years) of effective geophysical parameters for elucidating global climate change and water circulation mechanisms.

The GCOM mission is a two series of satellites, GCOM-W for observing water circulation changes and GCOM-C for climate changes. The GCOM-W with a microwave radiometer onboard will observe precipitation, vapor amounts, wind velocity above the ocean, sea water temperature, water levels on land areas, and snow depths.

Launch date: May 18, 2012

Global Change Observation Mission - Water
"Characteristics of SHIZUKU" (GCOM-W)

World's Largest Revolving Space Antenna AMSR2

The Advanced Microwave Scanning Radiometer 2 (AMSR2,) which will be loaded onto the GCOM-W, is a sensor to observe radiometers, or microwaves emitted naturally from the ground, sea surface and atmosphere, using six different frequency bands ranging from 7 GHz to 89 GHz. The strength of a natural microwave is determined by its characteristics and moisture, including the surface condition and temperature of the material. Although it depends on the frequency, the microwave is very weak. AMSR2 will detect such weak microwaves at an altitude of 700 kilometers and measure the strength of them with a very high accuracy. For example, by measuring the strength of a microwave emitted from the sea surface with the AMSR2, we can understand the water temperature of the sea surface to an accuracy of 0.5 degrees Celsius.

The antenna of the AMSR2, which receives microwaves from the ground, arc scans the ground surface at a ratio of one turn every 1.5 seconds and observes an area approximately 1,450 kilometers wide in one scan. Using this scanning method, the AMSR2 can observe over 99 percent of the Earth's area in just 2 days. The diameter of the antenna is about 2 meters, making it the world's largest observation sensor aboard a satellite. The height of the rotating part is about 2.7 meters and the weight is about 250 kilograms. The AMSR2 can keep rotating such a large and heavy antenna at a speed of one turn per 1.5 seconds for 24 hours a day and more than five years without a minute of rest.

Major Characteristics

International Designation Code 2012-025A
Launch Date May 18, 2012
Launch Vehicle H-IIA Launch Vehicle No. 21
Location Tanegashima Space Center
Shape 2 box shape with wing-type solar array paddles
Approx. 4.9m×3.0m×5.1m (Depth)
(Length between the tips of the paddles: 17.7 m)
Weight 1900 kg
Orbiter Sun-Synchronous Subrecurrent/ Recurrent
Altitude 700km
Inclination Approx. 98 degrees
Period 13:30±15min


Aug. 6, 2008
To Preserve Our Earth