Preliminary Results of Stereo Photogrammetry during DEEPWAVE

Photogrammetric analyses of time-lapse stereo images of cloud patterns upstream of the New Zealand Alps during DEEPWAVE are presented. The focus upstream is based on previous results highlighting the importance of moisture on mountain wave amplitude. The Hokitika airport, around which the cameras were deployed, is also where an Integrated Sounding System (ISS) was located, which was the primary source of upstream vertical profiles. Images were taken during any research flights over New Zealand from 2 June to 23 June 2014.

The process of capturing stereo photographic cloud images closely follows the methods used in Terrain-Induced Rotor Experiment (T-REX) by Grubisic and Grubisic (2007). Two identical cameras were positioned with a separation baseline of 500 to 800 meters. To ensure parallel fields of view, each camera was placed in the center of the other's view and rotated ninety degrees toward the target area. Synchronized images were then taken every five to ten seconds to capture the evolution of the cloud over time. Since the photos were taken in the afternoon, before the flight operations, knowing how the cloud was changing aids in determining what type of cloud structure was persisting overnight. Precise GPS locations of the cameras were recorded so triangulation can be used to determine the exact location of the cloud/clear-air boundary. These intricate triangulation calculations were performed using the Camera Calibration Toolbox available for MATLAB.