0229:39 Takeoff Hobart, climb to 16,000'
0237:16 First balloon aquisition: 46:12.63 S 147:55.16
0249:26-0303:16 Level at 16,000'
1000 fpm descent to 10,000'
0311-0322:34 Lidar leg, southbound across circle
0322:34-0344:13 500 fpm sounding to 100'
0344:13-0414:13 CW 30 min Lenschow circle at 100'
Start 46:22 S 148:35 E Balloon 46:26 S 148:35 E
90/270 climb to 500'
0417:01-0447:01 CCW 30 min Lenschow circle at 500'
90/270 climb to 1700'
0450:06-0520:06 CW 30 min Lenschow circle at 1700'
90/270 climb to 3000'
0523:23-0553:23 CCW 30 min Lenschow circle at 3000'
Nominally below inversion, but occasionaly above it
90/270 climb to 4000'
0556:49-0626:49 CW 30 min Lenschow circle at 4000'
Start 46:51.6 S 149:37.8 E Balloon 46:49.69 S 150:11.65 E
0627:40-0639:40 Porpoise leg northbound across circle at inversion
Turned southbound at 4500'
0642:44-0655:39 500 fpm sounding to 100' (south of front), then reregistered to balloon
0655:39-0725:39 CCW 30 min Lenschow circle at 100'
90/2170 climb to 500'
0728:50-0758:50 CW 30 min Lenschow circle at 500'
90/270 climb to 1700'
0802:04-0832:04 CCW 30 min Lenschow circle at 1700'
90/270 climb to 3000'
0835:32-0905:32 CW 30 min Lenschow circle at 3000'
Turn into northbound porpoise leg
0906:29-0917:29 Porpoise leg across circle at inversion
Spiral climb to 10,000'
0922:50-0936:30 Lidar leg at 10,000', southbound across circle
End 47:48.0 S 152:25.2E Balloon 47:46.24 S 152:26.78 E
1018 Last balloon contact: 1017:17 at 47:56.95 S 152:49.84 E at 836 m
Climb to 16,000' enroute to Hobart
0943-1038 Level at 16,000'
Descent into Hobart
1112 Landed Hobart
The second flight of this Lagrangian sequence was aparently quite successful. The balloon was acquired shortly after leaving Hobart, and we stayed with it throughout the entire flight. We aligned the southern edge of our first circle to start 4 nmi north of the ballon position on the 100' leg, and then let the pattern advect with the wind until the start of the second set of circles. There was a correction on the order of 20 miles to start the second 100' leg 4 nmi north of the balloon. Apparently the second pattern stayed closer to the balloon than the first.
The conditions varied quite a bit across the circles. At the southern edge, nearest the balloon, there was considerable sunlight and cloud-free air. Over most of the pattern the cloud tops were in the range of 3-4000'. But at the northern edge of the circles we passed into a very different type of cloud: there was a sharp boundary between the low clouds and a deck that had its top at 8000'. The Hobart preflight sounding showed this 8000' deep boundary layer, and we flew over it the entire ferry to the site. Fortunately, only a few minutes of each circle passed into this regime, so most of it was the lower, more broken clouds. We did encounter a shower of ~10 seconds duration on the second 100' passage under the deeper cloud (~0711).
During the first porpoise leg, the boundary layer seemed to slope down to the north. The inversion on the southern edge was 3800', dropping to 3400' in the middle and 3000' just prior to passing into the deep cloud bank. On the second stack, however, we were clearly above the inversion on the southern part of our leg at 3000'. The inversion was now at 2800' on the south end and back to 3300' in the middle. On at least one occasion we saw an ozone spike in unusually dry air near the northern edge of the second 1700' circle (~0502:30-0503:30), suggesting that some air had been drawn down from above the inversion. There was a substantial windspeed gradient with altitude, from <10 m/s at 100' to 15-20 m/s at 3000'.
The 100' and 500' circles were free of cloud and should provide an excellent set of observations of the change in aerosol chemistry since the sunrise flight. The chemistry must have been heavily impacted by aqueous phase chemistry. It will be interesting to see whether the chemistry was affected by the significant gradient of conditions across the circles: on the south and west we saw quite a lot of sunlight, while the northern edge was under a deep cloud bank.
The variation in the inversion height will make it impossible to calculate turbulent fluxes from the 3000' and 4000' legs, but they should prove interesting from an aerosol standpoint: as we skirted the tops of the clouds, we encountered regions of elevated MSA and CN concentrations. Clearly such cloudy regions represent a large fraction of the Earth, so the mechanisms by which sulfur species are oxidized are very important. However, since our instrument package has been optimized to study clear-air processes, we need to focus if at all possible on clear air in the next Lagrangian series.