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Show Daisy 4 7 - 4 April 19 6 7: This test was made using a release from an isopropy lamine generator at Emerald Mountain. A series of tracks 6. 5 n. miles from the release site is shown in Figure 43. At this downwind range the plume was approximately three miles wide. Track 2 2 is of interest in - - that it shows concentrations to 40 nuclei per liter 21. 5 n. miles from the relea?e site and a plume approximately five and a half miles wide. The Mt. Harris radiosonde for the test showed neutral conditions to 14, 000 ft. MSL. Daisy 52 - 22 December 1967: Figure 44 is a sounding for a very stable case where the plume was trapped below 8, 500 ft. MSL. The outer set of tracks (Figure 45) was 5 n. miles from the release site. Here the plume .. remained fairly narrow with very high tracer concentrations. Track 9 was the track shown previously in comparing the two tracer systems. The plume on this track was 1. 7 5 n. miles wide. On the tracks at 5 miles no tracer was found below 7, 500 ft. MSL or above 8, 500 ft. MSL. In closer, the plume did have more vertical extent. The plume was apparently trapped completely - within the inversion layer appearing in the sounding of Figure 44. = Daisy 37 - 10 January 1967: - -- .,, ,, .. ( ii This case is a particularly interesting stable case. An aircraft sounding and the Mt. Harris radiosonde are plotted in Figure 46. The aircraft sounding shows an inversion to 8, 500 ft. MSL, while the sonde shows an inversion at a slightly higher level. The upper level winds at Mt. Harris show light SW winds to 10, 500 ft. MSL and NW winds above. The mean release site wind was 229 degrees at 4. 3 mph, and neither agree with the behavior of the plume. If the original data _f rom a pibal taken from Steamboat Springs on the morning of the test are examined closely, the wind between the fourth and fifth minutes was from 066 degrees, which is in agreement with the observed direction of plume travel. A series of tracks taken 3 n. miles west of the release site on a north-south line are shown in Figure 47. At 8, 000 ft. MSL the plume was fairly wide (2. 5 mi. ). At 8, 250 ft. MSL it was somewhat narrower. By 8, 500 ft. MSL the track was characterized by a very narrow band of high tracer concentration. Then at 8, 750 and 9, 000 ft. MSL, directly above this area of high concentration, there was a slightly broader band of lower concentrations. This ''leaking through" on one edge of the plume is possibly due to an area of increased vertical mixing over some terrain feature. In any case, the plume structure varied radically in a vertical distanc_e of 250 feet. Fewer tracks could have led to any one of several different conclusions about the structure of the plume in this case. The very wide spread of the plume in a short distance observed on the lower tracks is not uncommon for stable cases. Fuquay, et al (1963), used a standard deviation of wind direction of 6 degrees to separate between "steady" wind directions and cases with meander or trend. In the mountainous terrain location of these tests the value of 0 is nearly always larger than six degrees. 75 |
