On the day prior tu each nuclear detonation, a formal detailed briefing was given to the Scientific Director, the Test Manager, and his Advisory Panel coveri.g all foreseeable ways in which weather might influence the success and safety of the test. All such briefings included wind speeds and direction predictions to at least the maximum cloud height obtainable, expected changes in wind during the day, thermal stability, clouds, precipitation, trajectories of aerosols, the effect of wind and thermal structure on the diffusion and deposition of effluent materials, and the maximum radiation dosages that could conceivably result on and off the Test Site. Changes, if any, from these predictions were presented at subsequent briefings just prior to arming each device. In fact one of the major factors in arriving at good predictions was the series of “wind runs” usually at one-half hour intervals up to zero time(fig. 12). Most of the programs remain in effect as a further assurance of safety in the event of the release of any radioactivity from underground tests, Radiological Surveillance Routine programs were and are conducted continuously within a radius of approximately 300 miles from the Nevada Test Site by the U.S. Public Health Service. . ee<3 3 ay Cannes im . #, Aircraft Monitoring 4 i “os * . at : . * 2 t . oy aa ra Oe uh atts ny eM ee iw . eh . we Rate ee . AL eo + fem - ee Gedy Ne Shey eee --f, + . “4.00 woe - wits Woes ye OMe Gei Oo a OF: fey ee tes ae | Nott atic ‘ee woot atts, oy ro Maeva: . . OMS WD abe wey a Fe TESAM : ' . os oe te aye ene @." a “oP . ! . . ‘a Se i . Sam. mf i Sa , - Te ” so * _gt OS at a. . . aa : . . . FIGURE 12.~The Weather Station at the Nevada Test Site sends radar-observer balloons to the upper atmosphere to check on temperat ures, dew points, humidity and wind velocities. The radar tracking instrument on top of the station charts wind velociti es and directions. essed most northern hemisphere data, much of it electro nically, and used the fastest and most modern techniques in producing forecast charts of the large scale features of the atmospheric circulation. The Mercury station, having more local information and the benefit of numerous studies of local meterological conditions, adjusted the NMC information to makeforecasts having the highest possible accuracy for NTS. 38 Since 1962 the U.S. Public Health Service has owned and operated two aircraft for cloud sampling. Prior to this date, this function was accomplished by the U.S. Air Force. Each aircraft carried equipment to collect airborne activity both particulate and gaseous. Both planes carried equipment for continuously monitoring the gamma radiation. Additional U.S. Air Force planes equipped for cloud sampling and tracking were available and were on call. Arrangements were madefor the use of another special aircraft for radiological monitoring surveying at H+24 hours. The capabilities of aircraft monitoring continue to be maintained. Mobile Ground Monitoring Mobile ground monitoring teams were deployed in the downwind sector prior to each test to supplement the routine surveillance which was a part of the continuous surveillance program. The downwind sector was determined by information obtained from the U.S. Weather Bureau personnel assigned to the NTS. These monitoring teams consisted of two men. Each team was equipped with beta-gamma survey 39