Flight summary, DC-8 Okinawa-Hong Kong 03/10/2001
Title: China outflow to Yellow Sea
Objectives: (1) to sample boundary layer outflow from China to the
Yellow Sea around a surface High over the western Pacific; (2) to sample
frontal and convective outflow along the transect from the Yellow Sea to
Hong Kong
Execution: The DC-8 headed NW and then N from Okinawa (26N, 128E)
well into the Yellow Sea (38N, 125E) with extensive profiling in the boundary
layer It then flew along a N-S transect back to Hong Kong (22N, 114E),
mostly at high altitude but with a vertical profile and a long boundary
leg getting into Hong Kong
Results: The flight was a success (1) Extensive pollution was observed
in the Yellow Sea, with considerable structure At 32-34N and below
5Kft CO concentrations approached 500 ppbv and CO2 was in excess of 380
ppmv Further N the air below 5Kft was cleaner, as expected from the shift
in surface winds (now blowing from N Korea) but a highly polluted layer
was sampled at 8 Kft (2) The transect S into Hong Kong identified
strong biomass burning pollution plumes from 20 to 30N and at 28-32 Kft
altitude (CO in excess of 200 ppbv), and a pollution layer of considerable
latitudinal extent was also observed at 10 Kft
Meteorological Summary DC-8 Okinawa to Hong Kong
Relevant Flow Patterns
Surface-An
anticyclone was centered between southern Japan and Okinawa, with clockwise
flow around it. Thus, surface winds in the Yellow Sea mostly were from
the south. The exception was northerly flow at the extreme northern point
of the flight track. Farther south, easterly flow covered the southern
half of the flight track. No fronts were in the area.
Middle
troposphere-The low level anticyclone near Shanghai dissipated by the 10,000
ft level. However, a short wave trough was oriented along the western shore
of the Yellow Sea. A major subtropical anticyclone was centered near
15N, 150E. Westerly flow covered the flight track in the middle troposphere.
Upper
troposphere-Flow patterns were similar to those in the middle levels. The
jet stream was located near 35N. The flight track entered the right
rear (entrance) region of the jet streak that mostly extended southeast
of Okinawa. Westerly flow covered the area. Trajectories indicated
that some of this air had passed over parts of Southeast Asia.
Relevant Cloud Patterns
The
Okinawa area had extensive clouds at low, middle and high altitudes. These
clouds generally were located between 22 - 30N. Conditions were
much improved over the Yellow Sea, with only scattered stratocumulus
and isolated cirrus being observed.