Stereophotogrammetry of Oceanic Clouds

This study extends ground-based stereophotogrammetry of clouds to oceanic settings, where there are often none of the landmarks used in traditional camera calibration. This paper introduces a zero-landmark calibration technique and tests it with two off-the-shelf digital cameras situated about 1 km apart facing Biscayne Bay in Miami, Florida. The precision of the stereo reconstruction is studied theoretically, and the accuracy of the reconstructions is validated against lidar and radiosondes. The stereo cameras are able to accurately reconstruct a histogram of cloud-base heights from a single-image pair, a task that requires tens of minutes of observation from a cloud lidar. The stereo cameras are also able to accurately reconstruct horizontal winds in cloud layers with a temporal resolution in the range of 30 s to 5min, compared to once every 12 h for a typical radiosonde launch site.