SWOT Level 2 Radiometer: Atmospheric Water and Sea Surface Brightness Temperatures

SWOT's Advanced Microwave Radiometer measures sea surface brightness temperatures at three specific frequencies: 18.7, 23.8, and 34 GHz. This Level 2 dataset processes those measurements to estimate key atmospheric variables like water vapor, cloud liquid water, and wind speed, which are used to correct range delays for the mission's primary altimeter. The data consists of discrete measurements along two tracks approximately 30 kilometers to the left and right of the satellite nadir, supporting the joint NASA-CNES mission's goal of high-resolution ocean and inland water mapping.

Use Cases

• Correcting nadir altimeter range delays based on estimated wet troposphere content and atmospheric attenuation.
• Analyzing spatial patterns of atmospheric water vapor and cloud liquid water coincident with ocean surface measurements.
• Deriving sea surface wind speed estimates from multi-frequency brightness temperature data.
• Validating and calibrating models for tropospheric effects on satellite-based ocean topography.

Strengths

• Provides data from a dedicated radiometer on a major joint NASA-CNES mission launched on December 16, 2022.
• Measures at three specific microwave frequencies (18.7, 23.8, 34 GHz) for detailed atmospheric profiling.
• Data is processed with Precise Orbit Ephemeris (POE) and analyzed calibrations, with a latency of < 90 days.

Limitations

• Column names and specific row/size counts are not provided in any source, limiting precise understanding of data structure.
• License is ambiguously listed as 'other-license-specified' on Data.gov, requiring further investigation for reuse.
• The dataset's availability is limited to two specific swaths (30-km left/right of nadir), not full global coverage.

Provenance

Source

National Aeronautics and Space Administration (NASA) and Centre National d'Études Spatiales (CNES) via the Surface Water and Ocean Topography (SWOT) mission.

Collection Method

Satellite remote sensing via the Advanced Microwave Radiometer (AMR), a Jason-class radiometer, with processing using Precise Orbit Ephemeris (POE).

Time Range

Post-launch from December 16, 2022 onward; specific end date not provided.

Freshness

2026-04-09 21:51:32.266139

Geography

Global coverage along the satellite's ground track, with measurements focused over oceans and inland water bodies.