Flight Report, Flight #28, 12 December, 1995 Stratocumulus-Radiation, Ship Flux intercomparison 2301 Takeoff Hobart, climb to 18,000' 2320-0035 level at 18,000' above altostratus enroute to stratocumulus region 0012 Approaching edge of altostratus deck - not clear to stratocumulus below 0030 Discussion with Ace-operations revealed that statocumulus field was closed in above by altostratus 0035 retrun heading for radiation runs in altostratus 0050:50-0105:50 Lidar leg at 13,000' altitude above altostratus - 45S 144E 0110:40-0125:40 Radiation leg at 8500' about 300' below altostratus base - high OH 0129:30-0144:30 Radiation leg at 11,100' about 300' above altostratus top 0148:20-0203:20 Radiation leg at 10,500' in cloud about 200' below cloud top 0020-0035 Profiling of stratucumulus below altostratus - 45.2S 143.6E 0246 Head west along stratucumulus top to 46S 143E 0305 Turn NE toward ship continuing along stratucumulus top 0322:55-0352:55 CW 30 min Lenschow circle at 100' - patches of drizzle start 45.1S 144.3E 0359:05-0429:05 CCW 30 min Lenschow circle at 100' - much less drizzle start 45.1 S 144.1E 0436:35-0506:35 CW 30 min Lenschow circle at 500' start 45.3S 144.4E 0508-0518 Porpoise leg along inversion 0518-0528 Extend for calibration below inversion 0532-0552 cloud top-following leg 0555:30-0525:30 CW 30 min Lenschow circle at 100' start 44.3S 145E 0526-0546 Sounding above circle to 10,000' at 500'/min 0546 Climb to 15,000' for return to Hobart 0630 Land at Hobart The objectives of this flight were to measure the radiation environment and microphysics of stratocumulus and produce a flux intercomparison with Disco. On transit out to the expected stratocumulus region conversation with Ace-operation indicated that the stratocu was covered by altostratus. The altostratus was very uniform and flat so radiation legs were flown on that cloud deck. The cloud top was at about 10,800' and was about 600' thick. Fifteen minute runs were made at 300' below the cloud base, 300' above the cloud top, and in the cloud about 200' below cloud top. Very high OH observations were reported above and below the altostratus layer. Radio conversations with Disco revealed poor weather including drizzle and weak inversion aloft. Stratocumulus below that altostratus was selected for profiling of cloud droplet characteristics. We then approached Disco with the intent to fly straight legs for consentrations of gases if drizzle was present and circles for fluxes if drizzle was absent. The profile down to the vicinity of Disco revealed a weak inversion at about 1200' with a mixed layer below to the surface. The profile aloft showed increasing theta to a second inverion at about 2200-2400. Stratocumulus populated a layer variably from 1000' to the upper inversion. No drizzle was reported at Disco (5 nm north) and so a circle was flown at 100'. The first circle at 100' was judged to be too inhomogenious (CN varied from 750 to 250/cc) and contaminated by drizzle. Therefore a second circle was flown 20nm to the west. This circle was was much more homogeneous (CN about 250) and very little drizzle was reported. We flew the next circle at 500' and then porpoised across the top for entrainment estimates. The entire layer from 1000' to 2200' was included in the porpoise to characterize the layer up to the second inversion. We then flew a final circle at 100' for time-differences. A profile above the circle at 500'/min ended the maneuvers for this flight. The profile revealed as many as five distinct stable layers from the surface mixed layer up the the altostratus layer at about 10,000'. The low solar flux in the surface mixed layer may help interpret the flux calculations.