# Global Change Observation Mission

> project of long-term observation of Earth environmental changes

**Wikidata**: [Q3108984](https://www.wikidata.org/wiki/Q3108984)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Global_Change_Observation_Mission)  
**Source**: https://4ort.xyz/entity/global-change-observation-mission

## Summary
Global Change Observation Mission (GCOM) is a long-term Japanese Earth-observation satellite program designed to monitor global environmental changes. The mission operates two satellite series—Shizuku (GCOM-W) for water-cycle observation and Shikisai (GCOM-C) for climate monitoring—providing continuous data on Earth’s oceans, atmosphere, land and cryosphere.

## Key Facts
- Classified as an Earth observation satellite, a subclass of artificial satellites designed to observe Earth from orbit
- Operates two active satellite components: Shizuku (GCOM-W) and Shikisai (GCOM-C)
- Maintains 5 Wikipedia language editions: English, Farsi, French, Indonesian and Japanese
- Listed under Wikidata topic category “Category:Global Change Observation Mission”
- Freebase identifier /m/02qjx3c documents the mission in the 2013-10-28 publication of Q15241312

## FAQs
### Q: What does GCOM stand for?
A: GCOM stands for Global Change Observation Mission, Japan’s long-term satellite program for tracking Earth environmental changes.

### Q: Which satellites are part of GCOM?
A: The mission currently comprises Shizuku (GCOM-W) for water-cycle variables and Shikisai (GCOM-C) for climate and carbon-cycle measurements.

### Q: Is GCOM only a Japanese project?
A: Yes; the satellites are developed and operated by Japan, but the open data serve the global climate-science community.

## Why It Matters
GCOM supplies uninterrupted, multi-sensor records that feed directly into climate models, weather forecasts and environmental-policy assessments. By flying both microwave and optical payloads on separate platforms, the program separates the measurement of water-vapor, precipitation, sea-surface temperature and vegetation dynamics, reducing error propagation between variables. The open-data policy gives researchers in developing nations free access to calibrated, long-term records, narrowing information gaps that previously limited global-change studies. Because the mission is designed to operate for 15+ years with overlapping successor satellites, it underpins the continuity requirements set by the Global Climate Observing System (GCOS), ensuring policy makers can detect and attribute environmental trends with confidence.

## Notable For
- Dual-satellite architecture dedicates one spacecraft to water cycle and one to climate/vegetation, minimizing spectral interference
- Provides one of the longest systematic records of combined passive microwave radiometer and second-generation global imager data
- Officially categorized under the Earth observation satellite class, giving it a formal place in the global EO taxonomy
- Maintains multilingual public documentation across five Wikipedia editions, an unusually broad language spread for a single national mission

## Body
### Program Scope
GCOM is a Japanese long-term Earth-observation initiative optimized for climate-change monitoring. The project goal is to deliver consistent, calibrated data sets that quantify variations in the atmosphere, oceans, cryosphere and land surface.

### Satellite Constellation
The mission currently fields two satellites:
- Shizuku (GCOM-W) carries the Advanced Microwave Scanning Radiometer 2 (AMSR2) and focuses on water-vapor, precipitation, sea-surface temperature and soil-moisture retrievals.
- Shikisai (GCOM-C) hosts the Second-generation Global Imager (SGLI) and measures clouds, aerosols, ocean color, vegetation and surface temperature.

Both spacecraft occupy sun-synchronous orbits, providing near-global coverage every few days.

### Data Access & Impact
Data products are distributed free of charge through the Japan Aerospace Exploration Agency (JAXA) and partner archives, supporting operational weather services, climate-model initialization and carbon-cycle research worldwide.

## References

1. Freebase Data Dumps. 2013