Mar 7:            First Hong Kong Local Flight

Flight 9 Summary – Hong Kong Local 1

This flight was intended to sample Asian outflow behind a frontal passage with the P-3B extending northward to the east of Taiwan and crossing the frontal boundary expected near 25N.

Results:

Observations included upper tropospheric conditions (15Kft) representative of tropical air to begin the flight (CO-70s, O3-20s).  Polluted conditions were first encountered around 10Kft at 22N (CO-300s, O3-90s).  In the frontal region, cloud modulation of composition was recorded with changes in CO of 75% and doubling of NOy in and out of convective cells.  CO values to the north behind the front were in the high 200-300 range.  On the return to Hong Kong a well defined pollution layer only 1000 ft in thickness was encountered at 9Kft.  Values in this layer for CO were double those encountered in the boundary layer and ozone values were almost quadrupled compared to BL values.  On the last boundary layer leg, a ship plume was encountered that lasted 15 seconds with enhancements in NOy, particles, SO2, and CO2 as well as a significant titration of ozone.