Upper Air Soundings al Sayan ae oe. yr gan It was not practice] to obtain upper air scundings exactly At H-hours ' ad XRAY DAY— The most significant sounding available before the tests, sco the eoundings reaching the highest altitudes have been plotted for Just be- the sounding made et 0300 loca] tine, did not reach the tropopause, fore and after the times the atonic clouds sere rising. local tipe scunding did apparantly reach the tropopuuse at 56,100 feet, but the in examination of the surface tesperatures and the temperatures at 400 aillibers permits a quick comparison and shows that the lapse rates were pearly the same on each of the three days. The small irreguiarities in the tempereture curves can hardly be seid to have affected the formation of the atomic clouds in a significant manner. These data are thought to be lens representative than the actual temperature data, particularly near the surfece; and not much cun be deduced by studying the relative humidities produced by the rein Showers which occurred just before H-hour on RAY DAY. - The most significant feature of the upper air soundings with respect to the formtion of the atomic clouds is the indicated height of the tropopause. During the time of the teats the height of the tropopause seemed to be conaistently between 54,000 and 56,000 feet. On XRAY and TOKE DAYS it is asuumed that the atrong temperature invereion which existe at the tropopause stopped the already decelerating atomic clouds, and that the topo of these clouds came to rest at the base of the stratoephers. The tempernture curve is dashed where it is believed to be doubtful, YOKE DAY- Unfortunately on TOKE DAY there was no sounding vhich showed the charactor of the tropoapharic inversion, but the 0300 local tine sounting does show that the temperature stopped decreasing above 54,100 feet. The small figures to the left of the temperature-helght curve indicate relative humidity. point given above that level appears to be i: error. Thea 0800 Bacause of nurral conditions over tropical areas in the latitudes of Eniwetok, it may be uscunmed that the temperature-helight curve tutns sharply at tha tropopause and that the shallow isothermal layar ia actually part of the large stratospheric inversion, Therefore, in the calcvlationsa which follow, it is | further sasumed that the YOKE DAY cloud stopped rising at approximtely 55,000 feet. ZEBRA DAY- On this day the height of the tropopause is clearly shoun to be 54,420 feet on the 0300 local time sounding, but this value waa of no use in tha cloud calculations because the cloud did not reach an altitude above 35,000 feet, It may be noted that a slight tempersture inversion la show by the 29,100 and the 29,900 foot levele at 0600 local tims, This inversion may have Slowed the Z:BHA DAY cloud, but it is not bellewed that such a smal) inversion would have had noticeable effect on vigorously rising clouds such as those an TRAY and TORE DAYS. 1"