Global Daily Integrated Water Vapor Over Oceans At 0.25-Degree Resolution

Integrated water vapor measurements derived from the AMSR2 microwave sensor aboard the JAXA GCOM-W satellite. The dataset provides daily statistical mean values on a 0.25-degree grid, covering ocean areas only. Data production began after the satellite's launch in May 2012.

Use Cases

• Analyze spatial and temporal trends in atmospheric water vapor content using the daily mean values on the 0.25-degree grid.
• Validate and calibrate climate model outputs for total precipitable water over ocean regions.
• Study the relationship between integrated water vapor and other hydrological parameters like precipitation and cloud liquid water.
• Compare ascending and descending track observations to investigate diurnal cycles in atmospheric moisture.
• Assimilate water vapor data into numerical weather prediction models to improve forecast accuracy.

Strengths

• Global spatial coverage over oceans on a 0.25-degree latitude/longitude grid.
• Data derived from the AMSR2 sensor, which has a 1450 km swath and 7 microwave frequency bands.
• Provides separate statistical means for satellite ascending and descending tracks.
• Long-term record supports climate trend analysis, with data collection starting in 2012.

Limitations

• Spatial coverage is restricted to ocean areas only, with no land observations.
• Missing data is represented by the value -32768, and error values range from -32761 to -32767.
• The dataset's temporal completeness depends on daily satellite coverage and processing.

Provenance

Source

Japan Aerospace Exploration Agency (JAXA).

Collection Method

Level 3 data produced from AMSR2 Level 1B and Level 2 inputs, calculating daily statistical means via simple arithmetic averaging at each grid point.

Time Range

Data collection began after the GCOM-W satellite launch on May 18, —2012.

Freshness

Daily statistical period with data overwritten by latest versions; update frequency is tied to satellite operations.

Geography

Global coverage, but limited to ocean areas only.