Project #2002-112 IDEAS Phase 2
Instrument Development and Education in Airborne Science
J. Stith, et al.
NSF/NCAR C-130Q Hercules (N130AR)
Jeff Stith's RF01 Summary
A successful flight was conducted today for the first IDEAS2 flight. Sampling was conducted near and north of Cheyenne, Wyoming. After a brief hold at 8,000' we climbed above the clouds to 16,000' and did clear-air reverse track maneuvers at 170 and 200 knots around 19:48 (UTC). This was followed by sideslip maneuvers at 170 and 200 knots at 19:52. We then descended into a stratocumulus deck between about 15,000' and 9,000' ( about -10°C to +1 °C) until about 20:55. Racetrack type flight patterns were used. Sampling was done by descending at 1000-foot increments. A substantial shear zone was observed in the mid regions of the cloud. We were not able to descend below the cloud base at 9,000 feet, but found a hole and circled for clear-air microscope slides. We hit our own wake at 20:57:17. The cloud was interesting, as it produced significant aircraft icing, including the possibility of supercooled large droplets near the shear zone. Sustained supercooled liquid water was found at about 0.3 g/m3.
We then (21:00) climbed through, then above, the sc deck and headed towards a region of higher convective tops that were isolated at their tops and merged with the sc at lower levels. These were sampled from 20,000 feet (-21°C) to 9,000 (+1°C) feet in 3000 foot increments. Microscope slides were taken at several points outside of the cloud at the cloud upper levels. There was ample liquid water (around 1 g/m3), and surprising little ice, even at cold temperatures, although patches of ice were occasionally found.
We then proceeded back towards JeffCo IFR at 10,000' and during the trip home, we found some of the highest ice concentrations (around 22:15) encountered ample concentrations of ice particles of various types. We broke into the clear about 10 minutes out, cancelled IFR and did below-cloud sampling for the last part of the flight. We then made a low approach at JefCo, proceeded to overfly the Marshall site twice for calibration of the AIMR before landing.
Most instruments were working properly, but we will review their status in more detail at the next IDEAS meeting. One of the King probes (PLWCC1) broke midway through the status sampling (20:37). The HVPS was on, but the winds display is not ready yet. Half the Nezorov (Total Water) was working, the other half will await a repair to the control box. MCR channel 7 was inoperative, but the rest appeared fine. AIMR had some display problems and its performance is under review. John Hallett's instruments were mostly working, except for a power problem to the total water sensor.
Jeff Stith
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