The Physics of Cloud Modification

Abstract

Publisher Summary The present position of cloud physics is reviewed, and the progress that has been made toward the goal of controlling or at least modifying significantly, the phenomena occurring within natural clouds is summarized. The chapter discusses the salient points of the physical theories of cloud and precipitation processes that have undergone such rapid evolution in the past few years, and tries to call attention to the principal implications that these theories have for prospects of control of certain links in the chain of events leading to precipitation. The chief goal of man's efforts at cloud modification is simply to cause more precipitation to fall upon selected continental areas than would occur by wholly natural processes. The chapter discusses the basic question of how there happen to be clouds and rain processes to modify in the first place and to inspect the magnitudes of certain parameters of the hydrologic cycle that influence the scope of potential modification methods. In this chapter, certain scale factors and characteristic magnitudes are examined. Present status of cloud and precipitation physics is discussed. Recent developments in cloud modification techniques are given. Although the subject of evaluation of cloud-seeding programs is largely outside the scope of this chapter, it discusses the evaluation difficulties just enough to see the important role they have played in the history of the past decade of modification efforts.