270
SAMPLE CALCULATIONS OF PARTICLE TRAJECTORIES
H-3,
H-3,
H-3,
H-3,
H-3,
H-3,
H-3,
H+9,
H+9,
H+9,
H+9,
H+9,
H+9,
H+9,
H+21,
H+21,
H4+21,
H+21,
H+21,
H+21,
H+21,
Time
hours
H+33
H+33
H+33
H+33
H+33
H+33
H+33
H-3,
H-3,
H-3,
H-3,
H-3,
H-3,
H+3,
H+3,
H+3,
H4+3,
H+3,
H+3,
H+9,
H+9,
H+9,
H+9,
H+9,
H+9,
Time
hours
H+15,
H+16,
H+16,
H+15,
H+16,
H+15,
H+21,
H+21,
H+21,
H+21,
H+21,
H+21,
H+27,
H+ 27,
H+27,
H+27,
H+27,
H+27,
Measured winds aloft at Bikini, Enlwetok, and Rongerik Atolls, Reference 70.
2,000
10,000
20,000
30,000
40,000
50,000
Altitude
feet
Vertical-motion charta of the wind fleld (computed values), Reference 71.
16,000
25,000
30,000
40,000
60,000
80,000
10,000
Altitude
feet
Constant-level charta of the wind field (iaogon-isotach analysis), Reference 70.
H+33
H+33
H+ 33
H+33
H+33
H+ 33
240 degrees, 25 knots.
j- Compute trajectory projection of particle through layer (uaed plotting device).
,
k. Add Vector 2 to end of vector 1 on plot (used plotting device).
lL. Latitude and Jongitude of particle at 60,000 foets 12° 02' N les @41' E£.
m. Timeto fall 6,000 feet (60,000 to 46,000): 1.21 hours.
160 degrees, 17 knots.
e. Compute trajectory projection of particle through layer (used plotting device,
Reference 68).
{. Plot Vector 1 (used plotting device).
g. Latitude and longitude of particle at 55,000 feet: 11° 47" N 166° 14' E.
h. Time to fail 5,000 feet (55,000 to 50,000): 1.16 hours.
i. 5,000-foot zonal wind (55,000 to 50,000), (time and space variation insignificant),
1.
Considering time-and-space variation of the wind fleld:
a. Shot Zunt: particle size, 75y; originating altitude, 60,000 feet; assume 3-br persistence of wind fleld.
b. Latitude and longitude of particle: 11° 30' N 165° 22° E at 0 time.
c. Time to fall 5,000 feet (60,000 to 55,000): 1.16 hours.
d. 5,000-foot zonal wind (60,000 to 56,000), (time and apace variation insignificant),
COMPUTATION OF PARTICLE TRAJECTORIES
3.
2.
1.
AVAILABLE DATA, SHOT ZUNI
TABLE B.29.
(2) Chart 2, H—3 hours, 40,000 feet, 12" 02' N, 165° 41‘ E: wind 240 degrees,
Interpolation for time-and-space variation of winds from constant level charts:
(1) Chart 1, H—3 hours, 50,000 feet, 12° 02 N, 165° 41’ E : wind 250 degrees,
(5) Chart 4, H+9 hours, 40,000 feet, 12° 02' N, 165° 41" E : wind 210 degrees,
(6) Interpolated value of wind in layer 50,000 to 45,000 feet: 230 degrees, 32
Considering time-and-space variation of the wind field as well as vertical motions:
a. Shot Zuni; particle size, 75; originating altitude, 60,000 feet; assume 3-hour per-
h. Using effective wind speed and still air time to fall 5,000 feet, compute trajectory
projection of particle through layer. (This reverse approach was used to implement plotting
with plotting device. )
.
I. Plot Vector 1 (used plotting device).
j. Continue this process interpolating for vertical motions and wind velocity from charta,
as a function of time, space, and altitude, until particle reaches surface.
knota.
d. From measured Bikini winds, obtain 5,000-foot zonal wind (60,000 to 55,000) at H+ 0
hours: 160°degrees, 17 knots.
e. Compute timeto fall, 5,000 feet in still atmosphere (60,000 to 55,000): 1.16 hours.
{. Compute corrected time to fall by considering vertical motions (60,000 to 55,000),
0.76 hour.
g. Compute effective wind speed through layer by considering corrected time to fall,
53 percent increase In failing speed or 53 percent decrease In wind speed: 160 degrees, 11
22' E: -19.5 cm/sec.
b. Latitude and longitude of particle: 11° 30' N, 165° 22' E at 0 time.
c. From computed vertical motion charta, determine by interpolation, the value of the
vertical wind through the 5,000-foot layer (60,000 to 55,000) at H+0 hours and 11° 30' N, 165°
sistence of wind fleid.
2.
plotting device).
p. Add Vector 3 to end of vector 2 on plot (used plotting device).
q- Continue the above computations until particle reaches surface.
knots at H+ 9 hours (to nearest 5 degrees).
(1) Final interpolated value of wind in layer 50,000 to 45,000 feet: 240 degrees,
37 knots at H+3 hours (to nearest 5 degrees).
o. Compute trajectory projection of particle through layer using final wind in N-7 (used
40 knots.
30 knota.
(3) Interpolated value of wind in layer 50,000 to 45,000 feet: 245 degrees, 38 knots
at H —3 hours (to nearest 5 degrees).
(4) Chart 3, H+8 hours, 50,000 feet, 12° 02' N, 165° 41‘ E: wind 235 degrees,
37 knots.
38 knots.
n.