Flight 13: Hong Kong-Okinawa Transit
This flight between Hong Kong and Okinawa was planned to include
a northbound leg along 124.5E beginning at 22N to the east of Taiwan
stretching into the Yellow Sea up to 37N, then south again into
Okinawa. Model products predicted strong low level outflow
north of 25N and centered between 4-12Kft.
Results: On the initial ascent from Hong Kong, an interesting
layered structure was observed in CO, O3, NOy, and CN. 10
distinct layers were observed between the inversion (4.5Kft) and
19Kft. Moving eastward to the south of Taiwan, the atmosphere
was fairly clean at all altitudes as expected. The first
polluted conditions were encountered on a descent to the surface
with CO exceeding 200 ppbv below 4000 ft. At 500 ft, NOy
exceeded 3 ppbv and NO was sustained in the 300-500 pptv range. During
this time northerly winds were encountered although southerly winds
were forecast. Over the Yellow Sea, CO maximized between
3000-7000 ft with sustained values above 400 ppbv and periods above
600 ppbv. Below 3000 ft, CO was less, around 200 ppbv. Conversely,
NOy and SO2 were maximized near the surface at ppbv
levels.