Abstract: Warm cloud electricity was extensively studied using a system comprised of raindrop charge radiosondes, raindrop charge-size radiosondes, cloud droplet charge radiosondes, space charge radiosondes, and electric potential.gradient radiosondes. More than 90 radiosondes were launched by balloon, mainly over the land, and also dropped from a helicopter. Special efforts were made to identify visually the cloud life stage at the sounding. The data were analyzed and arranged to present a composite picture of the electric charge profile with respect to the cloud life cycle. It was found that warm clouds produce excess negative charge in-cloud throughout their life cycle. Two charge separation processes appear to occur: one results in the negative charging of cloud droplets and raindrops in-cloud, which occurs mainly in the developing stage. The other produces the positive charging of raindrops near the cloud top, occurring mainly in the mature stage. The raindrop charge distribution in clouds with cloud ...

Abstract: The cloud points of polyoxyethylene dodecyl ether in the presence of different types of inorganic electrolytes have been determined. The cloud points can be expressed by the empirical equation: (C.P.)s⁄(C.P.)0=1+A\sqrtCs+BCs where (C.P.)0 and are the cloud Points with and without an electrolyte, respectively, Cs is the electrolyte concentration, and A and B are constants.

Abstract: The single or multi-component ejector is used for generating artificial protection clouds. The cloud is generated almost instantaneously for optimum protection and concealment from enemy observation. The materials (5, 6) to be ejected are each accommodated in separate chambers (3, 4) of the projection. These chambers are connected with a compression chamber which is connected when required to detachable compressed gas arrangement. The other end of the ejected material chamber faces the ejection opening (21, 22). These exit openings (21, 22) of the chamber are arranged so that different materials are mixed after their exit.

Abstract: The evolution of a precipitating convective cloud was studied by a time-dependent numerical model in which for the simplification of dynamical framework the domain under consideration was expressed by three regions: inner region of cloud, outer region of cloud and environmental region. Clouds are assumed to have no ice-phase. The size distribution of water drops is described using five size-groups.

Abstract: : The need for ice data in widespread Arctic regions is discussed and the requirement that data be objectively obtained by computer analysis of satellite imagery is established. Since former attempts at such analysis which used only information contained in the satellite image produced poor results, a method is established by which data external to the image are used. A decision tree is employed to arrive at a conclusion as to the contents of an incremental area. The decisions are (1) land vs. non-land, based on a map; (2) water vs. non-water, based on mean grey-level, and (3) ice vs. cloud, based on texture analysis of the image. If cloud is identified an a priori estimation of ice vs. water is used. The ice vs. cloud decision is the main work of the paper.

Abstract: In recent years the specializations of cloud microphysics, cloud dynamics, laboratory and theoretical cloud modeling, and radar meteorology have become so interrelated that they can hardly be considered as separate disciplines. By combined use of these techniques and tools, the cloud physicist has made significant advances in our understanding of the complex physics and dynamics of clouds. The purpose of this report is to review major advances in laboratory and field observations of clouds, cloud modeling, and radar meteorology.

Abstract: : A new evaluation of a ruby lidar ceilometer was performed at AFCRL as part of a program to evaluate the applicability of lasers to determine cloud height for airfield use. Comparitive measurements of cloud height were made with a standard Air Force rotating beam ceilometer (RBC). Examination of the test results shows the lidar indicates an accurate presentation of cloud structure. The RBC cloud return is affected by its geometry and by multiple scatter in the cloud. As a result, the measurement is not a true representation of cloud structure. These effects also bias the RBC to indicate higher cloud heights. However, the difference in cloud heights as measured by the two systems is not significant. Therefore, it is concluded that the lidar is a superior cloud height measuring device and both techniques provide operationally useful indications of cloud height. (Author)

Abstract: Low level aircraft equipped with Inertial Navigation Systems (INS) were used to define the vertical extent and horizontal motion of a cloud and to measure the ambient wind field. A high level aircraft, also equipped with an INS, took photographs to describe the horizontal extent of the cloud field and to measure cloud motion. The aerial photographs were also used to make a positive identification in a satellite picture of the cloud observed by the low level aircraft. The experiment was conducted over the tropical oceans in the vicinity of Florida, Puerto Rico, Panama and in the Western Gulf of Mexico. Results for tropical cumulus clouds indicate excellent agreement between the cloud motion and the wind at the cloud base. The magnitude of the vector difference between the cloud motion and the cloud base wind is less than 1.3 m/sec for 67% of the cases with track lengths of 1 hour or longer. The cirrus cloud motions agreed best with the mean wind in the cloud layer with a vector difference of about 1.6 m/sec.