Is ice multiplication a prominent factor in orographic precipitation?


  • Russell Shaffer
  • Robert Elliott


Weather Modification Research


Cloud top tempeature is considered to be the crucial factor for the production of nuclei which may be distributed in significant concentrations throughout the vertical extent of the cloud by  convective and turbulent mixing. The nuclei production curve for silver iodide shows the number of effective nuclei per gram  increasing exponentially with decreasing temperature at first,  with a lesser rate of increase at colder temperatures. The  average number of natural nuclei increases exponentially with  decreasing temperature. Since the coldest cloud temperature  normally occurs at cloud top, the number of nuclei produced  naturally or artifically at or near the cloud top temperature far overshadow the number of nuclei produced at lower and warmer temperatures. The high concentrations of ice crystals produced  near cloud top are distributed throughout the cloud via settling and mixing.....




Technical Notes and Correspondence