Flight 22: Midway-Kona Transit (7 April, 2001)
This flight was planned to head due south from Midway to 20N
then head due east in to Kona. A 0530 takeoff was planned
to avoid daylight bird traffic over the runway. While the
transit time to Kona did not allow the P-3B to take up a stationary
pattern during sunrise, a constant altitude was flown throughout
the sunrise period.
Results: Leaving Midway, the P-3B ascended to 17.5 Kft. At
this altitude, stratospheric influence was observed as O3 increased
from 50 ppbv to more than 100 ppbv while NOy increased slightly
from ~200 to ~300 pptv and CO remained steady at ~100 ppbv. Upon
descending, the most promising altitude for the sunrise portion
of the flight appeared to be about 13.5 Kft. Flight at this
altitude encountered modest variability for the first hour, however,
shortly after sunrise O3 rapidly rose from 70 ppbv to
130 ppbv and conditions became extremely dry. This complicated
any interpretation of OH with changing solar conditions. The
predominant signature over the remainder of the flight was of stratospheric
influence with several episodes of O3 exceeding 100
ppbv and O3 in the boundary layer of ~60 ppbv. CO remained
mostly around 100 ppbv or less except for a thin layer at 19Kft
containing 150 ppbv CO.