1415 Blocked out 1425 Takeoff, climb toward 19.5 N 157 W 1448:40 Arrive 15,000', BL top at ~5500-6000'
1456:00-1511:20 Leg AL, lidar leg at 157 W, 15,000', southbound (SB) from 19.5 N 1511;20-1526:00 1000 fpm sounding to 500' along 157 W. Winds 11 m/s @ 93 1530:00-1605:05 Leg A1, 2000', 157 W, northbound (NB). Plume 18.8 - 19.5 N. Dark.
1614:00-1633:45 Leg B1, 157.5 W, SB in twilight, 1000', clouds obscure plume. 1640:40-1703:30 Leg B2, 157.5 W, NB at 3500'. Still cloudy, but some sulfuric.
1712:12-1728:20 Leg CL, lidar at 10,000', SB at 158 W. Lots of haze (plume) below. 1737:50-1816:10 Leg C1, 2800' NB at 158 W. Plume 18.5-19.7 N, winds 5.5 m/s.
1828:10-1856:00 Leg A2, 2800/1500', 157.3 W, SB. Plume 18.8-~20 N. 10+7 sulfuric 1901:25-1924:25 Leg B3, 1300', 157.6 W, NB. Plume 19.2-20 N. 1934:20-1959:45 Leg C2, 1200', 158.2 W, SB. Broad plume 19-20 N.
2021:20-2045:00 Leg A3, 1200', 157 W, NB. Highest sulfuric, no UCN. Plume 18.8-19.7 N 2052:40-2117:00 Leg AL2, lidar @ 10,000', 157 W. Mostly cloud-free view of plume. 2120:00-2150:00 Leg A4, 7000-100' sounding, 500 fpm thru plume, 157 W.
2153 Lenschow yaws, pitches, speed runs 2223 Landed HNL 2234 Blocked in at Circle Rainbow Aviation
The transmitter on the smart balloon was damaged on launch from the Big Island, so we had no balloon to track. Thus we elected to use in situ wind oservations to move our observation points downwind.
This was a highly successful flight to study the evolution of plume chemistry. Although low clouds were a problem with some of our early legs, A1 was flown entirely in the dark, in air which contained volcanic SO2 that had never been exposed to sunlight. B1 was more hampered by clouds, but it too was in the barest twilight, so photochemistry was not a factor. No sulfuric acid vapor was seen on these predawn flights, but it was virtually always evident in the later flights, for which photochemistry became a factor. We may not have exactly resampled the same air we sampled on the predawn flights, but we certainly came close to it and bracketed its location well.
The last series of legs at 157 W gave us a good column-closure opportunity: The plume was mostly cloud-free (not totally, though), and we got both a good lidar run over it and a profile down through the densest part of the plume. There were very high levels of sulfuric acid vapor, but virtually nowhere on the entire flight were there any ultrafine particles.
This flight should provide an excellent dataset for watching the evolution of sulfur chemistry with sunlight and the growth of particles in the presence of high levels of sulfuric acid vapor.
-Barry Huebert