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<br />I appreciate the opportunity given me by the Arizona Academy of Science <br /> <br />to present a written discussion of Osborn's paper in lieu of discussion <br /> <br />before the live audience. <br /> <br />Is cloud seeding as represented by the Arizona Drought Relief Operational <br /> <br /> <br />Program (ARIDROP) of 1971 a valid technology, capable of cost-effective <br /> <br /> <br />use even while it still undergoes improvement; or is it open to such <br /> <br />serious risk of adverse effect that application should be proscribed <br /> <br /> <br />pending results of further experimentation? In this key question, Osborn <br /> <br /> <br />opted for the latter conclusion on three grounds, all open to grave <br /> <br />criticism. <br /> <br />The Rainfall Anomaly Pattern <br /> <br />One of his grounds is the presence of positive rainfall anomalies alleg- <br />edly upwind, and negative anomalies allegedly downwind, of the cloud- <br />seeding targets. But which way !!!! the wind blowing? During the period <br />from July 17 through August IS, 1971, the 6 p.m. daily winds-aloft obser- <br />vations made and published by the Environmental Data Service (see refer- <br />ence) for Winslow, Arizona, near the center of the target area, yield <br />the following information for the wind at cloud-steering levels from <br />700 to 400 mb: <br /> <br />Direction N <br />Number of days 14 <br /> <br />NE <br />5 <br /> <br />E <br />4 <br /> <br />SE <br />1 <br /> <br />5 <br />2 <br /> <br />sw <br />o <br /> <br />W <br />1 <br /> <br />NW <br />3 <br />