Statistical Analysis of Cloud Layers and Derivation of Motion Directions of Two Layer Clouds

Abstract

The daytime sky at Toyohashi city was observed every five seconds from April 2021 to December 2021 by using two all-sky cameras. Based on the images, the number of the cloud layer was statistically analyzed for every hour. The results indicate that two-layer clouds occupy a large temporal fraction as well as one-layer clouds. Therefore, the motion of the two-layer clouds was examined by the optical flow analysis with Lucas-Kanade method. Two directions were clearly obtained from the polar histogram of the angle of the optical flow vectors.