Neyman J, Scott E L, Wells M A
Statistical Laboratory, University of California, Berkeley, Calif. 94720.
Proc Natl Acad Sci U S A. 1973 Feb;70(2):357-60. doi: 10.1073/pnas.70.2.357.
The principal subject of this report is a comparison of precipitation on days with seeding with that without seeding, averaged over those rain gauges that on each particular day were "downwind," "upwind," or to the sides. Two estimates of relevant wind directions are used, based on successive radiosondes at Tucson that bracketed the scheduled time of seeding. By use of these radiosondes, the apparent effects of seeding on rain in downwind localities 90-180 miles (145-290 km) away from target were found to be an apparent 45% loss of rain (P = 0.002) and an apparent 34% loss of rain (P = 0.028), respectively. Other results indicate considerable geographic heterogeneity.
本报告的主要主题是对进行播撒作业的日子与未进行播撒作业的日子的降水量进行比较,这些降水量是在每个特定日子处于“下风处”、“上风处”或两侧的雨量计的平均值。基于图森市连续的无线电探空仪数据(这些数据涵盖了预定的播撒时间),使用了两种相关风向的估计方法。通过这些无线电探空仪,发现在距离目标90 - 180英里(145 - 290公里)的下风地区,播撒作业对降雨的明显影响分别是降雨明显减少45%(P = 0.002)和降雨明显减少34%(P = 0.028)。其他结果表明存在相当大的地理异质性。