INDOEX C-130: FLIGHT 15, 19 March 1999 Objective: Indirect Cloud Forcing Mission Mission Scientist: A. Bucholtz Summary: This 9hr 17min mission sampled the microphysical and radiative properties of two low-cloud systems to the northwest of Male, each embedded in different regions of the pollution plume coming off of the Indian sub-continent. The first cloud system was located at approximately 9.75N, 73.5E - 71.4E. East-west 25 minute legs were performed above the cloud/haze layer, in cloud, just above cloud, and just below cloud. Two dropsondes were launched approximately half way and 2/3 of the way along the high-altitude leg (the first sonde did not have wind data). A steady descent and a spiralling ascent profile were also done. After completing the stack over the first cloud system, we ferried to a different cloud field further to the northwest (approx. 12N, 71E) hoping to get into a more polluted region of the plume. (Unfortunately, problems with the Satcomm phone on the plane prevented us from getting updated meteorology from the Ops Center, so we located the new cloud system on our own.) Time constraints, and problems with the C-130 data system prevented us from performing a full altitude stack over this cloud system, but we did get east-west legs just above cloud, in cloud, just below cloud, and at 100 ft. The initial part of the ferry home was done at an altitude of 10,000 ft to sample the peak of the elevated upper haze/pollution layer. On return, dropsondes were launched over both KCO and Hulule from 17,000 ft. On our descent and approach into Hulule we performed 5 min level legs at 4,500 ft and 2,000 ft for lidar intercomparison. This turned out to be a very successful flight. While no pollution gradient between the two cloud fields was initially observed in the preliminary data, this mission should prove to be an interesting case because of the unique pollution conditions seen--an elevated, deep pollution layer with a thin dust layer below this, while the clouds were embedded in the less polluted boundary layer below. These conditions had not been seen before during the INDOEX IFP. UTC 03:31 (8:31 LST) Taxi 03:36 Take-off 03:39 SABL is down; scanning motor can't find its set point; can't be fixed in flight 03:51 (10,500 ft and climbing; 5.06N, 73.4E) Cirrus above; scattered stratocu below 04:00 (15,000 ft and climbing; 5.7N, 73.3E) Cindy reports problem with XCNCC; she would like to temporarily shut down DSM to fix. I asked her to wait until we reached altitude. 04:11 (18,000 ft; 6.37N, 73.2E) Cirrus above; scattered cu below 04:12 DSM was cycled to try to get XCNCC back; appears to have worked. 04:28 (7.6N, 72.9E) Thin cirrus above; widely scattered cu, stratocu below 04:36 (8.2N, 72.8E) Clear to thin cirrus above; widely scattered cu, stratocu below 04:56 (9.5N, 72.5E) Clear to thin cirrus above; scattered cu, stratocu below 05:00 Satcomm phone to Ops Center got fried - we're on our own 05:06 (18,000 ft; 10.2N, 72.4E) Heading to 9.5N, 73.5E to work cloud system over there; clear to thin cirrus above; scattered cu, stratocu below 05:13 (9.9N, 72.7E) Clear to thin cirrus above; scattered cu, stratocu below 05:19 (9.8N, 73.1E) Heading to 9.75N; clear to thin cirrus above; scattered to broken stratocu below 05:24 (9.75N, 73.46E) Turning to line up for above cloud run 05:26 Digital picture #62 05:27 (9.72N, 73.5E) Start 25 min above cloud run; Digital picture #63 05:30 (9.73N, 73.3E) Clear to thin cirrus above; scattered cu, stratocu below 05:34 (9.75N, 72.9E) Cirrus patch above; otherwise clear; scattered cu below 05:39 (approx 9.7N, 72.5E) Dropsonde (Errol reports it will not have winds) 05:47 (9.72N, 71.97E) Dropsonde - good winds 05:53 (18,000 ft; 9.72N, 71.41E) End leg; turn and reverse course; clear to thin cirrus above; scattered stratocu below 05:58 (9.7N, 71.4E) Start descent to 100 ft; clear above; hazy, scattered stratocu below; spike in CN @ approx 16,000 ft 06:05 At 11,200 ft increase in CN and scattering beginning; getting hazy visually. 06:08 1st peak @ approx 3,000 m 06:18 Cloud tops: 3,200 ft, cloud base: 2,340 ft 06:22 (100 ft; 9.73N, 72.9E) Scattered cu, stratocu above; hazy 06:37 (2,400 ft; 9.73N, 73.46E) Start in cloud run 06:39 XBSPD approx 40e-06 m-1; XBSPW approx 54e-06 m-1; XABS approx 12e-06 m-1, XCNCC approx 1,300 counts 06:44 (9.7N, 73.1E) Going in and out of cu and stratocu clouds 06:48 (2,400 ft; 9.73N, 72.87E) Going in and out of cu and stratocu clouds; XBSPD approx 36.6e-06m-1; XBSPW approx 38.7e-06m-1; XABS approx 6.7e-06; XCNCC approx 1,200 counts 06:52 Steady decrease in scattering coefficient along this track; going in and out of cu and stratocu 06:56 (9.72N, 72.4E) In and out of stratocu; XBSPD approx 32e-06m-1; XBSPW approx 43e-06m-1; XBABS approx 10e-06m-1; XCNCC approx 1,000 counts 07:04 (9.72N, 71.9E) In and out of stratocu; Tony Clarke reports seeing alot of dust above and below cloud - more than seen before during INDOEX. 07:05 XBSPD approx 31e-6m-1; XBSPW approx 42e-6m-1; XBABS is all over the place; XCNCC approx 800 Unk 07:10 (9.72N, 71.5E) Turning, climbing to do just above cloud leg 07:13 (3,400 ft) Start 25 min just above cloud leg; hazy above; scattered stratocu below; cloud tops seem lower than before 07:29 (3,400 ft; 9.7N, 72.43E) Very hazy above; scattered stratocu below; slow, but steady increase in scattering; XBSPD approx 38e-6m-1; XBSPW approx 38e-6m-1; XBABS approx 6e-6m-1; XCNCC approx 680 Unk 07:48 (9.75N, 73.5E) End leg; descend to just below cloud base 07:51 (1,700 ft) Start approx. 30 min run to West; very hazy out 08:04 (1,700 ft; 9.76N, 72.7E) Just below cloud bases; scattered stratocu 08:21 (1,700 ft; 9.71N, 71.75E) Hazy; scattered stratocu above 08:26 (9.7N, 71.5E) End leg; descending to 100 ft 08:29 (100 ft) Spiralling up to get above haze 08:43 (12,000 ft) Lots of cirrus above, it's all around us 08:45 (9.87N, 71.35E) Descend to 3,400 ft ferry 08:53 (3,400 ft; 10.28N, 71.2E) Ferrying to 11N, 71E; just above scattered stratocu; hazy above 08:57 (3,400 ft; 10.5N, 71.1E) XBSPD approx 36e-6m-1; XBSPW approx 42e-6m-1; XBABS approx 7.5e-6m-1; CO approx 1.8; TEO3C approx 28; XCNCC approx 680 counts 09:03 (3,400 ft) Heading to 12N, 71E; not much gradient in scattering or absorption 09:07 Tony Clarke reports dust starting to decrease, or just variable; hazy out; scattered stratocu below 09:15 WINDS went down 09:24 End leg; reversing course and descending into cloud; cloud tops approx 2,700 ft 09:28 (2,400 ft) Start 25 min. in cloud leg (heading South) 09:34 WINDS is back 09:35 WINDS is frozen again 09:43 (2,400 ft) WINDS is still down; going in and out of scattered stratocu; no droplet data 09:53 Aborted in cloud run since no droplet data available; descend to below cloud for 5 min. 09:54 (2,000 ft) Hazy; scattered stratocu above; start below cloud run; Bill can't get WINDS to boot 09:59 (2,000 ft) Reversing course 10:02 (2,000 ft) Start 2nd 5 min below cloud leg 10:07 End leg; descending to 100 ft; Decided not to do the satellite overpass due to cirrus 10:10 (100 ft) Start 20 min run; WINDS may be back but cockpit display not working 10:25 End leg; climbing up into cloud and reversing course 10:28 (approx 2,400 ft) Start in cloud leg 10:31 Going in and out of scattered stratocu 10:42 (approx 2,400 ft) Going in and out of scattered stratocu; hazy 10:52 (approx 2,400 ft) Going in and out of scattered stratocu; hazy 10:59 End in cloud leg; climbing to 9,000 ft to get in peak of haze layer 11:03 (7,200 ft and climbing) Hazy; cirrus above; scattered stratocu below 11:05 Tony Clarke reports 7,500 ft is max in haze layer 11:07 (10,600 ft and climbing) Starting to climb out of layer; cirrus above 11:08 (11,500 ft) 10,500 ft looks like it will work; descending 11:10 (10,000 ft) Near top of peak in haze layer; start 20 min run; cirrus above; scattered cu below 11:20 (10,000 ft) Ci above; haze, scattered cu, stratocu below 11:30 End leg; climbing to 17,000 ft 11:37 (17,000 ft) Ci above; hazy, scattered cu, stratocu below; Mark reports that we flew out of haze layer a few minutes before we started climbing to 17,000 ft; 2-7 min ago we were in a transition region between haze and free troposphere; last 2 min we were in the free troposphere 11:55 (17,000 ft) Ci above; scattered, somewhat convective cu, stratocu below 12:13 (17,000 ft) Dropsonde over KCO (no wind data); ci above; scattered cu, convective cu below; nice convective cell ahead 12:23 (17,000 ft) Dropsonde over Hulule (with wind data); start descent into Male 12:31 (4,500 ft) Start 5 min lidar intercomparison run 12:37 End leg; start descent 12:39 (2,000 ft) Start 5 min lidar intercomparison run; Bill reports WINDS/DSM down for past 15 min 12:43 (2,000 ft) Passing through some clouds 12:44 End leg 12:52 Land Debrief: Clarke: Everything worked ok; got some interesting observations (dust layer below pollution layer Sara: Everything worked fine, including other nephelometers, but maybe a software glitch; she needs a day for calibration Hudson: Mostly things worked ok; had some problems, but not when in clouds Cindy: Everything worked fine, but she needs a day to trouble-shoot C130 data system Olga: Everything worked Shelly: Everything worked fine Mass spec: Worked well most of the time; problems with SO2 in clouds SABL: Crashed early in flight and never came back