Retrieved wind speed from the Orbiting Carbon Observatory-2

Satellite measurements of surface wind speed over the ocean inform a wide variety of scientific pursuits. While both activeand passive microwave sensors are traditionally used to detect surface wind speed over water surfaces, measurements ofreflected sunlight in the near-infrared made by the Orbiting Carbon Observatory-2 (OCO-2) are also sensitive to the wind speed. In this work, retrieved wind speeds from OCO-2 glint measurements are validated against the Advanced MicrowaveScanning Radiometer-2 (AMSR2). Both sensors are in the international Afternoon Constellation, allowing for a large numberof co-located observations. Several different OCO-2 retrieval algorithm modifications are tested, with the most successful beinga single-band Cox-Munk-only model. Using this, we find excellent agreement between the two sensors, with OCO-2 having asmall mean low bias against AMSR2 of -0.22 m/s, an RMSD of 0.75 m/s, and a correlation coefficient of 0.94. Although OCO-2 is restricted to clear-sky measurements, potential benefits of its higher spatial resolution relative to microwave instrumentsinclude the study of coastal wind processes, which may be able to inform certain economic sectors.