This flight was a shared objective mission that was used to 1) Examine the vicinity of convective cumulus clouds near Cape Grim for evidence of nuclei formation and associated gaseous precursors, 2) carry out a boundary layer intercomparison study with Cape Grim and 3) carry out column closure in clear (but continentally influenced) air on the lee side of the island near 41S and 150N. All three objectives met with success and no instrument failures were reported.
High ultrafine particles of several thousand per cc were found in layers in clean air aloft often near 11,00' and higher. These appeared associated with levels of cloud top detrainment. Concentrations in cloud were generally lower than out of cloud.
The Cape Grim comparison was flown at about 240' in clean boundary layer air with CN concentrations stable and about 400/cc perturbed only once for about 40sec (about 01:58) with drizzle.
Two radiative closure missions were flown in continentally influenced air on the East side of Tasmania. The first was in more variable aerosol and was shortened to have only one boundary layer leg. The second was moved further south and east of Hobart and had more homogeneous aerosol at somewhat lower concentrations. Two boundary layer legs were flown in this mission. Both appear to have provided good intercomparisons with the satellite overpass and all instruments were functional.
APPROX.
GMT
TIME COMMENTS
23:05 Takeoff and ferry at 16,000' to Cape Grim area
00:11 Ultrafine (UCN) start to increase to about 1000/cc
00:13 Spiral down to top of lower cloud near 41S, 144E
00:15 "Burst" of UCN at 11,500'(passed through enhanced layer).
Rodney says Dp 11-13nm. H2SO4 increasing to 5x10^6, OH
climbing.
00:17 Spiral descent continues to surface, H2SO4 dropping
00:22 Just below cloud base
00:26 Start 5min 200' leg at surface
00:31 End 200' leg and climb to 2000' just below cloud
00:34 Start 5 min leg at 2000'
00:39 End 2000' leg and climb 1000'/min to 12,000'
00:41 Out of lower Cu tops, temporary increase of H2SO4 and UCN
above 4,500'
00:47 UCN increasing faster than CN above 8000'
00:49 Try to hit cloud top, over Cloud at 4,500', all
concentrations drop temporarily. Lyan alpha and RH dropto
very low values.
00:51 Fly along cloud, some UCN
00:55 Approach cloud all CN increase with greater increase of
UCN.
01:00 UCN increase near 10,000'
01:08 CN, UCN increasing to 6000/cc at 17,200' detrained region
of old cloud??
01:14 just below little cloud, Concentrations dropping but
relative UCN increasing - smaller particles
01:18 Small ice cloud, UCN disappear in cloud & all CN lower.
Turn and climb about 2,000' more.
01:21 18,000' UCN increase and lyman alpha
01:24 Coming near cloud, lots of UCN but few in cloud
01:33 Entering cloud-low CN & UCN
01:36 Descend to surface over Cape Grim, high UCN & CN 9,000'
to 13,000'.
01:55 Start Cape Grim intercomparison @ 240'.
01:57 Brief drizzle below cloud
02:10 End 240' leg and climb to 10,500' into high UCN layer for
lidar profile above intercomparison leg.
02:29 End leg and climb to 13,000' and ferry over to Column
Closure study area near 41S and 150E.
03:20 Climb to 18,000'and start lidar leg to examine area
03:37 We have moved from high wind are with large seas and
whitecaps to calmer seas better for satellite retrieval.
NO WHITECAPS - extend lidar overpass to south.
03:56 End lidar overpass at 18,000' at -43.83S & 150.3E. Turn
and descend at 1000'/min.
04:10 Aerosol layer encountered at 3,000'
04:14 Satellite overpass.
04:18 End descent, reverse course at surface and start 30min
100' leg. Aerosol variable becoming more stable at end
of leg, 44S and 150.3E.
04:37 Abandon scheduled second below inversion leg due to
variability and climb out in reverse direction relative
to descent.
04:47 Peak of high particle layer near 4,000' (pollution?)
between 2,500' and 6,000'.
05:01 End climb. Move to other region further south for second
lidar leg along about 43.5S and between 150.5E and
151.5E.
05:17 End West to East lidar leg, reverse course and start
descent at 1000'/min. Pollution layer is higher, thinner
and less concentrated than previous area.
05:34 End descent, reverse course and start leg at 100'
05:49 End leg at 100', reverse course and climb to 3,800' at
about 400'/min.
06:20 End 3,800' leg, reverse course and climb to 14,000'.
06:35 End Climb, UCN up to 5,000/cc.
06:47 Try cloud penetration at 13,500. Slightly lower
concentration in cloud for all nuclei but little change.
All concentrations also about 3 times higher than below
cloud during ascent.
06:58 Lenschow maneuvers.
07:03 In base of cirrus from older cloud outflow.
07:06 Into thicker "bumpy" clouds.