CYGNSS Satellite Ocean Surface Radar Cross Section Measurements

NASA's CYGNSS constellation provides calibrated Delay Doppler Maps (DDMs) measuring ocean surface scattering. The dataset contains daily files from up to 8 spacecraft, with a typical latency of 6 days from measurement. Version 3.1, produced by POCLOUD, supersedes Version 3.0 with improved antenna gain calibration and quantization correction.

Use Cases

• Retrieve ocean wind speeds by analyzing the Leading Edge Slope (LES) of the integrated delay waveform near the specular point.
• Calibrate ocean surface scattering models using the Normalized Bistatic Radar Cross Section (NBRCS) values from the Delay Doppler Maps.
• Monitor tropical storm development by tracking changes in Bistatic Radar Cross Section (BRCS) measurements with higher retrieval frequency from the 8-satellite constellation.
• Assess data quality for specific orbital passes using the provided quality flags, error estimates, and bias estimates included in the science records.
• Study radio frequency interference effects by comparing calibrated Power Received (Watts) in Version 3.1 data against previous versions.

Strengths

• Version 3.1 includes specific calibration improvements for antenna gain patterns and coarse quantization effects, correcting biases present in Version 3.0.
• Data is provided from a constellation of up to 8 spacecraft, enabling frequent global coverage, especially during targeted events like hurricanes.
• The dataset contains multiple derived scientific parameters including DDMA of NBRCS and LES, alongside engineering and geolocation parameters.

Limitations

• The typical data latency of approximately 6 days limits its use for real-time weather forecasting or immediate hazard monitoring.
• The number of active data-retrieving spacecraft can vary from the nominal 6-8, potentially creating gaps in spatial or temporal coverage on a given day.
• Specific details on total row count, file size, and complete column schema are not provided, complicating initial assessment of data volume and structure.

Provenance

Source

NASA Earthdata (POCLOUD)

Collection Method

Measurements from the Delay Doppler Mapping Instrument aboard the CYGNSS satellite constellation, processed into Level 1 Science Data Records.

Freshness

Daily file updates with approximately 6-day latency from measurement.

Geography

Global coverage, with emphasis on tropical ocean regions between 38° North and South latitude where CYGNSS operates.