OCR Text |
Show Weather Modification And Climate Control The Council of the American Meteorological Society, representing represent-ing the meteorological profession, in cognizance of the current public pub-lic interest in weather modification modifica-tion and control has adopted the following statements as best representing rep-resenting the present state of knowledge in this field. 1. The seeding of supercooled clouds with dry ice, silver iodide and similar materials will usually convert at least a portion of the cloud to ice crystals. 2. The seeding of relatively thin, supercooled layer clouds may open holes or valleys in the cloud deck but little rain or snow will result. 3. The seeding of small, inactive cumulus clouds will usually result in the partial or complete dissipation dissipa-tion of the clouds without the release re-lease of any significant amounts of rain or snow. 4. At best, seeding can be expected ex-pected only to trigger the release of precipitation from e x i s ting supercooled clouds. The release of substantial amounts of precipitation precipi-tation by either natural or artificial artifi-cial means requires the pre-exist-ence of moist air currents. 5. The weather conditions which appear to be most favorable for the artificial release of rain or snow are thus very much the same as those requisite for natural rainfall. rain-fall. For this reason it is extremely extreme-ly difficult to determine whether or not the results of a single seeding seed-ing experiment are favorable. Scientific knowledge of the physical physi-cal processes by which rain and snow are formed has not advanced to the point where it is possible to predict the results of seeding rain clouds. 6. There is very little evidence and no present scientific basis for the belief that we now possess the ability to modify or control the weather and climate of a major portion of the country. |