Flight Summary:
Take –off at 07:04UT. Found a pollution layer at 12-13kft during climb-out from Sao Tome. During transit to 15S we recognized sloping low cloud tops from 2S to 7S with sloping aerosol layers above. From 10 to 15S lidar curtain indicated mid-level clouds at the top of the outflow plume and embedded in the plume. This was verified during in situ sampling legs in the plume on the Northbound leg. First leg at 13kft was very polluted (80Mm-1 scat, 230ppb CO). Second leg at 8kft was less polluted (40-60 Mm-1 scat, ~200ppb CO). This was forecast qualitatively in WRF and GEOS-5, and linked to a younger plume at higher altitude. Boundary layer work between 12S and 9.5S found a fairly polluted BL (115ppb CO). Visual detection of low-level Cu well below flight level hinted at some decoupling of the BL. Profiling to the surface yielded different assessments on mixing state from different instruments. BL work was followed by extended run at 8kft, which HiGEAR used for extended testing. After ascent to 18kft and partial transit North, pilots informed flight scientists that there was an extra hour of time to use for science. Decision on-board was to use clear slot at 9S for square spiral and radiation work. This spiral happened in most clear conditions encountered in ORACLES-2018 yet, with minimal low-clouds in the FOV at low altitudes. During transit home, we flew an extended leg (1hr+) at 8kft, before ascending to transit altitude of 19kft. Landed at 15:08UT.
See flight report file for details.