Clouds electrification

This article has not addressed several subjects in the field of cloud physics. For cloud chemistry and cloud electrification, see Atmospheric Chemistry and Atmospheric Electricity. The topic of cloud radiation and optics is almost as broad as that of cloud physics itself The reader is referred to the Bibliography for information on this topic. 

Kll. Kunkel, W. B., The static electrification of dust particles on dispersion into a cloud, J. Appl. Phys. 21, 820 (1950). 

Static Electrification of Dust Particles. Kunkel (l Y) has made an extensive study of the charge and size distribution of particles ranging from 0.5- to 30-micron radius in dust clouds in air and has investigated both calm and turbulent conditions. 

Spontaneous electrification in coal-dust clouds. London Safety in Mines Research Board Paper 71. 

On the electrification associated with dust-clouds. Ibid., 25 481-494. Russell, Sir Edward J. 

If the particle is an electron, then ipif/ is proportional to the average electric density at x, y, z. if/if/, being independent of time, can be represented in space as a continuous cloud of electrification varying from point to point in a manner shown by the solution of the wave equation which has yielded if/. Although this cloud is fictitious and corresponds to a probability or to a time-average, it is very convenient to visualize its spatial symmetry, and even to look upon the electrical distribution as a real one. This in one sense illustrates the reluctance with which naive realism is forsaken. 

Any neutral atom or molecule can be schematized in terms of a positive centre surrounded by a cloud of negative electrification. If the positive centre is displaced from its equilibrium position, it will oscillate with a frequency v. According to the quantum theory, even in the lowest possible energy state, an oscillator possesses energy hvQ. Thus the atom or molecule wiU, from this cause alone, always... 

Cloud physicists draw on the well-developed sciences of chemistry, physics, and fluid dynamics to study these phenomena. Such topics as the thermodynamics of moist air, the physics of the growth of water droplets and ice particles, radiation, effects of clouds on climate, electrification, and chemical conversion processes are all part of this discipline. Major research tools include computers for numerical simulation and aircraft and radars for observation, along with wind firrmels and cold rooms for the study of the properties of cloud and precipitation particles. 

Figure 1 shows the mean annual distribution of the fractional area covered by clouds whose tops are above the 440 mb pressure level. All these clouds are likely to contain ice. The total atmospheric burden of ice is not known, but very crude estimates suggest it is around 10 to 10 kg. This mass is small compared with that (over 10 kg [5]) in surface ice and snow. Despite its relatively small abundance, atmospheric ice has considerable impact on global climate, the chemical composition of the atmosphere and of precipitation, and on thunderstorm electrification. Figure 2 represents the ice-related tropospheric processes to be discussed in this paper, and we will refer to this figure in succeeding sections. 

---