Mission 17, 6 Oct 2001 C-130 -- ITCZ mission, Darrel Baumgardner flight scientist, Dave Raymond mission scientist P-3 -- ITCZ mission, Carlos Lopez flight scientist List of tasks: 1. Intercomparison on way to 93 W, 12 N -- 600 ft, 6000 ft, 13000 ft legs, 5 min, wing to wing. 2. Dropsonde test -- 3 sondes from 18000 ft dropped in racetrack, descend in racetrack at 1000 ft/min to 100 ft, ascend same rate to 13000 ft. 3. Convective missions. 4. Calibration maneuvers. 5. S turns for Ophir calibration. 1534 - C-130 launches (first). Huatulco weather -- clear and hot except for high scattered cirrus. 1541 - A few whitecaps, prob. wind from E. 1548 - Continuing clear. 1557 - At 600 ft waiting for P-3 to catch up. Clear except for isolated puffs of cu. 1601 - Finishing 600 ft leg, going to 6000 ft. Scattered cu hum, scattered cirrus. 1608 - Now very clear. 1615 - End of 6000 ft leg, up to 13000 ft. Very hazy since departure. 1625 - Lever at 13000 ft, waiting for P-3 to catch up. Still clear below, cu hum patch ahead. Area of mature Cbs and some towering cu to S. 94.5 W, 13.2 N. 1634 - Finish 13000 ft leg, climb to 18000 ft. 1648 - We have isolated towering cu below us, with some lower clouds. Cbs to S. 1654 - Convective line 60 km ahead on radar, will drop sondes in 25 km. 1659 - P3 drops dropsonde, we are holding at 18000 ft, SE of drop point. 1703 - Start our drops. 1712 - All drops in the air. Descending in down sounding. 1724 - Now descending thru layer cloud at about 6000 ft. Trade cu around. 1728 - Thru a bit of trade cu near 2000 ft. 1730 - 100 ft, start up. 1741 - the convective system to S of us is propagating N, popping up new cells. 1746 - Lightning in convective system. 1756 - Heading for growing cell at about 94 W, 11.8 N, north of main band. Some tops already well above us. 1800 - Cells are growing on upshear, or E side. 1822 - At 13000 ft, ready to penetrate cells again. 1827 - Anvil blowing off to W. Going for cells growing on E end of system. 1840 - Jump to new development E along line. Tops just above us at 8000 ft. The whole area here is blowing up. 1856 - Descending to 3000 ft over dome of stratus a la Roger Smith. ???? - Heading for growing cu with tops a few thousand feet above us. 1922 - At 1000 ft -- uneven cloud base. 1925 - Heading for growing E end of cloud system about 50 m below cloud base. 1927 - Passing under E end of line -- rain to W. 1939 - Out SW side -- 90/270 and down to 100 ft. 1944 - Going NE -- will pass thru rain showers from the system. 1955 - SST and air temperature at 31 C! 2000 - Start racetrack sounding NE of rain area. 2023 - Head west to an active region of the major EW line. We will work NS across it. The convection of interest is on the W end of an outflow arc. 2039 - We made 3 passes thru towers -- near tops. Much weaker vertical velocity [than in first case study]. 2044 - Down to 13000 ft. The cloud is dying -- we'll do an autopsy. 2058 - The tower we are studying is still there, but it is essentially a fossil. All the clouds around here have a less enthusiastic appearance then earlier. 2103 - Will also penetrate some slightly healthier looking cu coming off outflow boundary. All clouds are showing negative buoyancy at 8000 ft. 2113 - Heading back thru at 3000 ft. 2123 - Heading thru N to S at 1000 ft. We just have small cu. Very murky. 2128 - Mixing ratio dropped off -- we are in outflow air. 2131 - 100 ft going NW. 2137 - Start racetrack sounding. 2142 - Doing sounding to 13000 ft. The major line has almost totally stratiformed out. 2155 - Heading toward home at 13000 ft. 2158 - Starting calibration maneuvers: speed run, yaw, pitch, reverse track, left and right circles, right and left slips. Do S turns. 2236 - Down sounding to 100 ft. Sounding is very dry. No clouds around. 2249 - 100 ft -- going to 1000 ft. 2250 - 1000 ft -- doing S turns. 2256 - Going to 6000 ft. 2302 - 6000 ft -- after 1 min do S turns. 2305 - Into a layer cloud coming off the land. 2320 - Recover Huatulco.