CYGNSS Satellite Delay Doppler Maps for Ocean Surface Analysis

Version 3.0 Level 1 science data provides calibrated Delay Doppler Maps (DDMs) from the eight-satellite CYGNSS constellation. The dataset includes geo-located measurements of Power Received, Bistatic Radar Cross Section (BRCS), Normalized BRCS, and Leading Edge Slope, produced by POCLOUD. Data from up to 8 spacecraft is typically available daily with a latency of approximately 6 days from the last measurement.

Use Cases

• Estimate ocean surface wind speeds by analyzing the calibrated Bistatic Radar Cross Section (BRCS) and Normalized Bistatic Radar Cross Section (NBRCS) values near the specular point.
• Monitor tropical storm and hurricane conditions using the higher retrieval frequency data from the 8-spacecraft constellation during special observation periods.
• Validate ocean wave models by comparing the Leading Edge Slope (LES) of integrated delay waveforms with coincident ocean surface roughness spectra from models like NOAA WAVEWATCH-3.
• Assess signal calibration quality by examining the provided error estimates, bias estimates, and quality flags associated with each Delay Doppler Map measurement.

Strengths

• Calibration validated against a large population of modeled values from the NOAA WAVEWATCH-3 oceanographic wave model.
• Data is sourced from a constellation of up to 8 spacecraft, providing multiple daily observations.
• Version 3.0 includes real-time correction for variations in GPS transmit power, improving BRCS calibration accuracy.

Limitations

• Specific row count, file size, and total temporal coverage are not provided in the description.
• Data has a latency of approximately 6 days, making it unsuitable for real-time monitoring applications.
• The number of active data-retrieving spacecraft can vary from the typical 6-8 under non-nominal conditions.

Provenance

Source

POCLOUD, utilizing the Delay Doppler Mapping Instrument aboard the NASA CYGNSS satellite constellation.

Collection Method

Satellite-based GNSS-R (Global Navigation Satellite System Reflectometry) measurements processed into calibrated Level 1 science data records.

Freshness

Last updated on 2022-08-07; daily data production with ~6-day latency.

Geography

Global coverage, focused on ocean surfaces between approximately 38° North and 38° South latitude due to CYGNSS orbit inclination.