Due to the fact that the cloudiness plays a critical role in the Earth radiative balance, the study of the distribution of different types of clouds and their movements is relevant. The main sources of such information are artificial satellites that provide data in the form of images. The most commonly used method of solving tasks of processing and classification of images of clouds is based on the description of texture features. The use of a set of local binary patterns is proposed to describe the texture image.
The paper presents the result of simultaneous observation of cirrus clouds by a lidar and an all-sky camera. The observation was started at 17:00, 24 March, 2016 and finished at 09:00, 25 March, 2016. The polarization lidar of V.E. Zuev Institute of Atmospheric Optics was used. The cirrus cloud was formed at 8000 m and went down to 4000 m at the end of observation. The linear depolarization ratio varied from 60% to less than 1%. The layer of quasi-horizontally oriented ice crystals was observed. Simultaneously, the all-sky camera pictured the 22 degrees halos while the lidar measured high depolarization ratio, which means that randomly oriented hexagonal ice particles were forming the cloud. The camera also pictured the Sundogs when the depolarization ratio tended to zero at about 21:30 that definitely indicates the quasi-horizontally oriented hexagonal plates. Absence of the Sundogs in the all-sky pictures while both the lidar sense low depolarization ratio, strong intensity and the specular reflection appears means that the cloud was formed by quasi-horizontally oriented particles with complex shape, i.e. snowflakes. The simultaneous lidar and all-sky camera observations seems to be a very prospective method to retrieve the microphysical properties of cirrus clouds.
This report discusses some simulation results of the angular distribution of brightness of the sky in the case of molecular scattering in the atmosphere for the benefit of the study of space-time changes of this distribution during the civil twilight.
This report discusses some simulation results of the angular distribution of brightness of the sky in the case of molecular scattering in the atmosphere during the civil twilight with solar zenith angles 90 ° - 94 °.
This article gives a short overview to method of direction determining and visible angular velocity of movement determining of cloudiness based on set of panoramic images of cloudy sky, obtained by “Fisheye” wide-angle lens.
This article gives a short overview to the modified algorithm of cloud fields images processing generated by digital camera. The article shows that the simultaneous measurement of the low bound of clouds with LIDAR allows to determine the direction and speed of the clouds movement at the LIDAR installation point. Also the articles provides the example of the clouds speed estimation based on experimental data.