This mission was designed to establish direct column closure between in-situ measured aerosol physico-chemistry, aerosol optical properties, in-situ column extinction and satellite derived radiances and optical depth. The extensive sulfate plume emitted from the Kiluaea Volcano into the clean marine boundary layer was the target since it has well defined properties dominate by sulfate and is at sufficient concentration to be readily measured by all techniques. It also provided an opportunity to assess the relationship of gaseous precursors to plume properties in contrast to the marine atmosphere adjacent to the plume.
A favorable transition from unsettled and cloudy conditions resulted in large cloud free regions in the vicinity of Hawaii on Nov. 6. Divergence in the vicinity of the islands resulted in light winds that kept plume concentrations elevated over large regions and facilitated our objectives. We started engines at about 6:00hrs and flew until 15:00 hrs. These times were selected to enable vertical profiles to be flown in conjunction with satellite overpasses at about 07:15 and 14:12.
The vertical profile for the first satellite overpass was flown at 17.5N and 158W. The initial descent was marred by a power strip failure for the essential Total Direct and Diffuse Radiometer (TDDR). This was replaced and the flight plan was modified to include another profile in order to complete the optical depth profile. Higher plume concentrations were aloft near 4,000ft with cleaner air near the surface. A second successful stacked profile in volcanic haze was also flown in near 17.5N and 159.5W and was better mixed up to the inversion. A third profile was flown in near 19.5N and 158W. A final volcano plume descent was coordinated with the afternoon satellite overpass at about 19.3N and 156.5W.
The mission was very successful with all radiative closure instrumentation operative and only a few minor and shortlived problems. Both satellite intercomparisons were accomplished and all objectives were met. The four profiles exceeded the three proposed and exhibited the range of column concentrations we had hoped for. The lidar performed well throughout the experiment in the downward looking mode. Successful complementary measurements indicated little evidence for new particle formation or gas phase sulfuric acid associated with the plume. Sulfur dioxide was variable and occasionally high. OH was successfully detected and numerous gas canisters were collected for later analysis.