0027:55 Takeoff, climb to ~20,000' southbound towards 139E 50S
Dryout at ~6200' during climbout
0100:00-0236:53 Level at 20,000'
Sounding to 10,000'
0300:30-0315:30 Northbound lidar diameter crossing at 10,000', starting at 50.16S 138.5E
Location chosen to center circle on last reported location of balloon #9
No balloons acquired at any time during flight
Spiral sounding @1000 fpm to 5000', then 500 fpm to 100'
0328:35-0358:35 30 min CCW circular pattern at 100', starting from northernmost point
90/270 climb to 1200'
0401:17-0431:17 30 min CW circular pattern at 1200'
Rain noted on windshield offf and on throughout remainder of flight
90/270 climb to 2500'
0434:06-0504:06 30 min CCW circular pattern at 2500'
90/270 climb to 3400'
0507:04-0537:04 30 min CW circular pattern at 3400'
0537:17-0548:00 Porpoise leg across diameter. In cloud, but large theta gradient
Climb to 5200', above surface mixed layer
0548:39-0618:39 30 min CCW circular pattern at 5200'
500 fpm descent to 100', at southernmost edge of circle, 48.8S 139.1E
0629:45-0659:45 30 min CW circular pattern at 100'
Climb to 10,000', then continued up because clouds were 14,500' deep
Lidar leg abandoned, since heavy clouds obscured the mixed-layer top
0720:00-0848:15 20,000' ferry back to Hobart
0907 Landing
The flight was a serious disappointment from the Lagrangian standpoint. The balloons which were to have been launched together at about 0100 were delayed, apparently by technical problems. No. 9, which was launched at about 0220, seemed the best candidate to follow, since the Disco had received a location from it at 0251 (49 deg 50 min S, 138 deg 29 min E). We adopted that location (corrected using in situ winds) as the center of our circular patterns, even though we never made contact with that balloon. The stack was advected with the wind, so we presume we drifted with #9, even though we never heard another location from it.
Unfortunately, we found ourselves in heavy clouds, with drizzle much of the time. The mixed layer deepened during the flight, from 4200' during our initial sounding to 14,000' of cloudy air without an obvious mixed-layer upper boundary by the time we left.We did note some wind-shear between the circles below 4200' and the circle at 5200'.
We had repeated radio conversations with Disco to determine balloon launch times and locations. It is unfortunate that when it became clear in the Ops Center that the weather had deteriorated, we did not have a procedure in place to terminate the balloon launches and preserve our remaining balloon resources for a later try. That feedback needs to be built into later lagrangian strategies.
We sought to troubleshoot the receiver problems. A preamp which was apparently expendable was removed, and still we received no signal from the balloons. An HF aircraft receiver was tuned to the frequency, 410.5, with no success. According to Disco, they could never keep contact with any balloon for more than 30 miles, which caused us to question whether the transmitters were actually achieving line of sight transmission. Disco also suggested that one balloon might have lost helium, since it was apparently dragging its bottle in the water.
Since the reliability of the balloons is questionable, it did not seem wise to try to quickly repair the receiver and try to find these particular balloons on a subsequent flight. Therefore, we recommended aborting this Lagrangian series. Because of the rainy, cloudy conditions, we had no desire to study this airmass on later flights anyway.