The Use of Sky Cameras to Validate and Augment Satellite/Radar Based Cloud Assimilation

Simulated visually realistic camera-like images of the sky can provide informative displays of 3-D model fields. Comparisons of simulated and actual camera images can help with model evaluation. Thus based on Numerical Weather Prediction (NWP) analysis of model conditions and the quantitative use of 3-D radiative transfer, color images of the current or future weather and land surface conditions can be rendered from any vantage point in a visually realistic manner. A comparison of these simulated images with space-, air-, and ground-based camera images offers powerful tools for subjective NWP interpretation and objective evaluation of NWP performance.

Cameras can also serve as data sources for hydrometeor data assimilation, augmenting satellite and radar data. We are testing an approach utilizing a cloud mask that is determined for individual camera images. The cloud mask defines both cloudy and clear areas in the sky. As a first step the clear areas represent slant paths that can have hydrometeors zeroed out in the analyzed cloud hydrometeor fields. Various approaches for a more complete analysis that includes the ability to add clouds will be discussed.