Observing clouds in 4D with multiview stereophotogrammetry

 

Authors

David Romps — Lawrence Berkeley National Laboratory
Rusen Oktem — Lawrence Berkeley National Laboratory

Category

Warm low clouds, including aerosol interactions

Description

To develop accurate theories and parameterizations of shallow cloud cover, we need measurements of clouds' horizontal dimensions, their elevations, their depths, the rate at which they are created, the rate at which they dissipate, and how all of these factors vary with changes to the large-scale environment. Only observations that are high-resolution relative to individual clouds in all four dimensions (space and time) can provide these needed data. Towards this end, a new ring of cameras has been installed around the SGP ARM site. Six digital cameras are situated in pairs at a distance of 6 kilometers from the site and with a spacing of 500 meters between cameras in a pair. These pairs of cameras provide stereoscopic views of shallow clouds from all sides; when these data are combined, they allow for a complete stereo reconstruction. The result, called the Clouds Optically Gridded by Stereo (COGS) product, is a 4D grid of cloudiness covering a 6 km x 6 km x 6 km cube at a spatial resolution of 50 meters and a temporal resolution of 20 seconds.