Validation of Saildrone Hurricane Observations with Coordinated Measurements from Buoys, Satellites, and Aircraft

In-situ surface data are critical for expanding our understanding of tropical cyclones (TCs) and improving intensity forecasts. However, collecting continuous, high-quality measurements simultaneously in the ocean and atmosphere in TCs is challenging. Moored buoys are capable but limited as they are immobile. Uncrewed and remotely operated surface vehicles such as saildrones help fill this gap, but since there are so few other measurements in the highly complex and dynamic TC environment, opportunities for data-quality assessments and validation are rare. This presentation focuses on the coordination efforts and results from co-located saildrone, wave-measuring drifters, moored buoys, gliders, aircraft-based measurements, dropsondes, and satellite-derived products in weak-to-moderate and extreme conditions. Comparisons between saildrone and dropsonde wind and pressure measurements show no significant differences for wind speeds up to 62 kt and pressures as low as 968 hPa. Likewise, comparisons with moored buoys show no significant differences in sustained wind speed, gusts, wind direction, SST, significant wave height, and dominant wave period. Additionally, comparisons with drifters show no significant differences in pressure, dominant wave period, and significant wave height. Near-surface humidity measurements are more challenging, and we found significant mean differences relative to co-located dropsonde and buoy data. Overall, the comparisons across numerous different platforms, variables, and ocean-atmosphere conditions show the high quality and value of the saildrone measurements while also revealing unique challenges associated with multiplatform intercomparisons in extreme conditions. The results from this study will also be useful aiding data assimilation and improving and validating other platforms.