INDOEX C-130:  FLIGHT 12, 13 March 1999

Objective:  Citation Comparison and Cloud Study

Mission Scientists:  T. Clarke and A. Bucholtz

The objective of this mission was to carry out a joint flight with the
Citation and to carry out a cloud study for clouds embedded in haze to
the North.  The Citation comparison was first and went smoothly.  The
C-130 took off first and scouted a cloud region NW of Male.  The Citation
flew to redevous near cloud at 6.33N, 72E.  In the meantime the C-130 flew
over cloud to the West and then back in cloud to the rendezvous point.
At 05:45 the two aircraft flew together with the C-130 at 14,000ft and the
Citation in cloud at about 3,000ft.  Both aircraft reversed course about
06:14 and continued with Citation climbing to 4,000 to stay in cloud.
Both aircraft then postioned themselves wing on wing about 06:30 for
20min side-by-side instrument comparison as Citation retuned to Male.
About 07:15 the C-130 broke off from the Citation and flew NW to about
7.5N, 72.15E for a cloud study.

The cloud study focussed upon modest boudary layer cumulu with most
bases near 0.5km and tops near 1.5km.  Pollution haze extended up to
almost 3km with a peak in pollution above clouds that had aerosol
concetraions that were several times more than below near cloud base.
Approximately 30 minute legs were flow above the haze, just above cloud
top, in cloud near cloud base, in cloud near cloud top and short legs
below cloud.  Many cloud penetrations and good statistics were optained
for this case of clouds embedded in and below significant pollution.
All in all the dual mission went very well; all objectives were met.

Nominal takeoff 8:30LST and Rendevous with Citation near 7N, 71E

UTC
03:46   Takeoff at (8:46:30LST)
03:58   Climbing above haze AT 9,000ft, scatter 6Mm-1
04:01   Cirrus thinning to NW
04:10   Lidar reports increase in layer form 0.8 to 2.5km, upper layer
         thickened and joining lower layer
04:17   More pollution - Digital image #32 (cloud in haze)
         Cumulus in dirty air below at (6.67N, 72.34E)
04:50   Call OPS center to direct Citation aircraft to 6 20'N and 72E
04:54   Haze starting at 2.8km
04:55   Drop to cloud level at 7.087N, 70.914E
05:01   1st cloud at 1,306m (4,200ft) and below main upper haze layer
         (1.5-2.8km)
05:06   Citation takes off
05:18   Turn and drop to 100ft
05:22   Higher sea salt evident - more than usual seen by OPC.
05:28   End 100ft leg and climb to 14,000ft
05:35   Pollution plume increasing with altitude.
         Scattering high - about 112Mm-1 at about 7,500ft
05:45   Start 14,000ft leg - some small cirrues above but OK
05:53   Turn heading 6odeg to get Citation nto more cloud.
06:08   Take 7.125N, 71.063E as new point for return leg; Citation at 3,000ft
06:14   Turn and start second run at end of turn
06:18   Citation visible on downward video,  Cirrus well south of us
06:26   Big cumulus ahead off to left, most cloud tops near 1.5km and base
         at 0.5km
06:29   Citation climbs to 4,000ft to stay in cloud
06:42   Citation climbs to 7,000 and C-130 drops to 7,000ft for instrument
         intercomparison.
06:49   Lidar looking down.
06:51   Start 20min nstruement comparison with Citation while heading back
         to Male.  Some big cumulus around us and small cumulus below.
06:53   3 Digital photos of Citation
07:14   End 20 min run in clear air, turn and return to clouds
07:21   Haze layer at 1.5-2.0km
07:28   End descent to 100ft and climb back into cloud level at 2,500ft
         (5.3N,73.15E)
07:47   Aerosol droping as we go northwest and minimum in big cumulus but
         no droplet shatter,  small cloud more wimpy with base rising
07:54   More sea salt evident in size data
08:00   Cimb to 12,000ft to see cloud region, Pollution above cloud layer
         with max at top of cloud - layer 1.2-2.8km.
08:03   Data system down
08:06   Climb and turn to north where there is less cirrus.
08:17   Start cloud overflight (7.5N, 72.15E) heading at 300deg.
08:35   Clouds thickening below (8.14N, 7.89E), base at 400m and top 1.2km
08:41   Turn to west at 8.35N, 70.42E heading 270.
08:44   Turn to WSW 8.33N, 70.203E
08:51   Start descent to cloud level
09:07   At 100ft then climb back to cloud
09:09   Cloud base at 2,500ft
09:10   Starting cloud run 3,200ft,  good clouds - some light drizzle evident?
09:39   Digital image #41 (cloud edge); #42 (clouds); #43 clouds
09:48   End in-cloud run and drop below cloud and reverse heading
09:51   Start below-cloud leg to west
09:58   End below-cloud leg and start spiral up in cloud
10:05   2,400ft Descend to above most clouds but below most haze
10:14   Digital iage #43 just above cloud top leg, base 500m and top 1,500m
10:16   Top of haze 2,900m with structure to it
10:22   Lidar shows very polluted;  f(RH)=1???, RHwet=80, RHdry=20
         DMA very refractory, OPC typical at 20% refractory
10:29   End above-cloud run and drop below
10:34   Start below-cloud run (W-E)
10:40   End below-cloud run (E-W)
10:44   Enter clouds at 4,500ft (W-E), a few big drops
10:53   DMA scans here look lie below cloud aerosol, not same as above cloud.
11:01   Start spiral down to surface 100ft (7.8N, 71.6E)
11:06   Level at 100ft then climb to 15,000ft, clouds up to inversion at
         1.4km but still haze above most of them
11:14   Digital photo #45 at 2,500m of cloud sticking out of haze
11:37   RAF Lenschow maneuvers
11:46   Start descent to KCO (6.1N, 72.65E)
11:49   Haze at 2,300m (7,000ft) but much weaker upper layer here
11:52   Clouds here
11:59   Start 100ft KCO leg along wind to test nephelometer heater
12:11   Abeam KCO - heater on (12:11:04)
12:22   End run and climb
12:32   Land