CYGNSS Satellite Ocean Wind Speed and Surface Slope Data

The CYGNSS Level 2 Climate Data Record Version 1.1 provides average ocean surface wind speed and mean square slope measurements. Data is collected by the Delay Doppler Mapping Instrument aboard the CYGNSS constellation of eight spacecraft, processed by POCLOUD, and has a latency of approximately one to two months from measurement. This version is a reanalysis product derived from SDR v3.0 Level 1 data, featuring improved calibration accuracy and long-term stability.

Use Cases

• Analyzing temporal trends in average wind speed for climate change studies using the time-tagged geolocated records.
• Modeling ocean surface roughness and wave conditions by correlating mean square slope (MSS) with wind speed data.
• Validating and improving numerical weather prediction models by assimilating the 25x25 kilometer resolution wind speed observations.
• Studying calibration stability and instrument performance by comparing this CDR v1.1 data with the SDR v3.0 source data.

Strengths

• Data has improved calibration accuracy and long-term stability relative to the SDR v3.0 source through a trackwise correction algorithm.
• Provides spatially explicit data with 25x25 kilometer resolution for wind speed and mean square slope.
• Includes co-located Delay Doppler Map (DDM) data subset used in the direct processing within the Level 2 files.

Limitations

• The dataset does not include a Young Seas with Limited Fetch (YSLF) wind speed product, making it unsuitable for measurements in and near the inner core of tropical cyclones.
• The trackwise correction algorithm causes some loss of samples that were present in the source SDR v3.0 data.
• Wind speed retrievals are inherently biased toward fully developed sea state conditions due to the correction constraint using MERRA-2 reanalysis winds.

Provenance

Source

NASA CYGNSS satellite constellation (Delay Doppler Mapping Instrument).

Collection Method

Reanalysis processing of SDR v3.0 Level 1 data using a trackwise correction algorithm.

Freshness

Data has a latency of approximately 1 to 2 months from the last recorded measurement time, with one netCDF file produced daily.

Geography

Global ocean coverage, determined by specular points corresponding to Delay Doppler Maps.