Assessment of CYGNSS Wind Speed Retrieval Uncertainty

作者：Ruf, Christopher S.^*; Gleason, Scott; McKague, Darren S.

来源：IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2019, 12(1): 87-97.

DOI：10.1109/JSTARS.2018.2825948

• Cyclone Global Navigation Satellite System (CYGNSS)
• geophysical model GMF)
• GNSS-R
• ocean surface wind speed

Measurements of near surface wind speed made by the Cyclone Global Navigation Satellite System (CYGNSS) constellation of GNSS-R satellites are evaluated and their uncertainty is assessed in two ways. A bottom-up assessment begins with a model for the error in engineering measurements and propagates that error through the wind speed retrieval algorithm analytically. A top-down assessment performs a statistical comparison between CYGNSS measurements and coincident "ground truth" measurements of wind speed. Results of the two approaches are compared. Overall performance, as determined by the top-down method, is decomposed using the bottom-up approach into its contributing sources of error. Overall root mean square (RMS) uncertainty in the CYGNSS retrievals is 1.4 m/s at wind speeds below 20 m/s. At higher wind speeds, an increase in the retrieval error is primarily caused by a decrease in the sensitivity of the ocean scattering cross section to changes in wind speed. In tropical cyclones, retrieval errors are compounded by unaccounted departures from a fully developed sea state. Overall RMS uncertainty in the CYGNSS retrievals is 17% at wind speeds above 20 m/s.

• 出版日期2019-1