Flight 14: Okinawa-Yokota Transit  

This flight between Okinawa and Yokota was planned to include a northbound leg along 124.5E beginning at 30N stretching into the Yellow Sea up to 37N, then south again before heading east toward Yokota AFB, Japan.  This mission was intended to sample the same area of the Yellow Sea as flight 13 to capture strong surface level outflow not present on the previous flight.  

Results:  On the initial ascent from Okinawa, a layer of elevated CO and NOy was observed between 5-10 Kft.  Clean chemical conditions prevailed over the early portion of the flight into the Yellow Sea down to 5 Kft, although a large dust plume was encountered at 10Kft.  The first polluted conditions were encountered on a descent from 5000 to 500 ft with the most polluted conditions persisting in the lowest 1000 ft.  CO was sustained above 700 ppbv and exceeded 1 ppm.  SO₂, NOy, and PAN were also sustained above ppbv levels.  Dust was also encountered several more times during the flight between 5 and 10 Kft.  Flying eastward toward Yokota, volcanic emissions were encountered at 4.5 Kft with variations in SO₂ of several ppbv accompanied only by enhancements in CN and H₂SO₄.  On the final leg into Yokota, O₃ reaching 122 ppbv was encountered at 18 Kft.