ZEBRA DAY Location of Center of Rising Atomic Cloud | from H~-hour until H~-hour plus 120 Minutes MINUTES THAT WIND ACTED OW CLOUD AT SACH 5,000 FOOT LEVEL METHOD OF COMPUTING LOCATION OF CANTER OF ATOMIC CLOOD TOP AT TIME IT REACHED MIGHEST ALTITUDE The graph of the agimth angles of the primary @lowd masse shows that the stomie loud moved tery little borizontally during the firet three minutes, Basause of the relatively light winde at lower levels and the rapid Frise of the stomio elowd, wind deta below 15,000 foet- have aot been sonsidered in these computations, The tims intervals given below have teen obtained by dividing tha eurve shows on the page Rips of the A Cloud Jato $,000 root segments, 2,500 fest On either side of the altitude is question, and reading off the iatersections of the plotted curve with the time ordinates, Theses ties intervals are ecasidered to be the hauber of miuetes that the upper vinds seted om the slowd at esek 5,000 foot level, Date up to 25,000 feet have beon eaed for the primary slowd mess en4 data for %,006 feat have bows aeed for the aloud projection. de the atemie slow! wee asted upon by the upper wisde during the 12.0 minates thet it ma rieiag, the top of the cloud was displaced a comeidereble élstanse fron the test site by the tins that it reached merinvn altitude, Tee apper winds et H-hour have been eotinated by eomsidering deta obtained several sours before and after H-hovr, Theee eatimted wied date give 6 sovameot of 4,4 sautioal piles is « direstioa from 2557, Thin inersese 1m distence between the cloud end the theodolite observation stations auat be comsidered if the tree altitude of the slowd is to be acmsidered. | Tae position of the eloud haa bees ealculated by joining together veotors ahiah are directed im eccordsnee with the upper wind at the $,000 foot Level in question end wbieh are proportions] in leagth to the tine tbat the cloud required fc pase through the altitude taterrel, The radii of the eireles are im neutioel miles, and the individesl veotdre are identified by figurwa signifying thousands of feet, feat, ?7O* 90° UPPER WDB AT F-ROOR Altitude Beareeg 10,000 20 10 15,000 20 1a 20,000 240 8 25,000 250 26 30,000 240 40 35,000 zn —Jimies 15,000 20,000 25,000 (20 +2.1) (94-20) (8.0 - 3.4) 2 a9 = 24 - 26 3,900 (22.0-10.2} - 4.0 LENOTHS OF VECTORS DW MAUTICAL MILES Kwok Altitude Hours Egote 15,000 0.9/60 5 10 1.4/60 3 -29- Magtios) = Ub = 2.6/60 3 2% = 4.0/0 x MO -