Central California Ozone Study (CCOS) - Desert Research Institute

CCOS Field Operations Plan Version 2: 5/31/00
achieve the required detection level. The samples will be analyzed for C 1 -C 7 carbonyl
compounds by HPLC with UV detection at AtmAA (Calabasas, CA).
The budget allows for collection and analysis of three or four sets of hydrocarbon and
carbonyl samples per flight.
2.6.8 Intercomparison Flights
Intercomparison flights will be performed between (1) the STI Aztec and STI Cessna
182, (2) the two UCD Cessnas, (3) the STI 182 and one UCD Cessna, (4) the STI Aztec and the
DOE G-1, and (5) one UCD Cessna and the TVA Twin Otter. The first three comparisons will
be made near Sacramento, the fourth near Fresno, and the fifth near Livermore. Each aircraft will
collect hydrocarbon and carbonyl samples in a clean location so that investigators can ensure that
their sampling systems do not contaminate the samples. This can be done as part of the
intercomparison flights or during initial test flights.
The intercomparison flights will compare measurements of ozone, NO, NOy, CO (when
available) temperature, relative humidity or dew point, and winds (when available). The aircraft
will compare clocks and GPS position systems on the ground prior to flight in order to facilitate
subsequent data processing and analysis. Flights will include spirals up and down to document
hysteresis and altitude effects, and will include traverses in the mixed layer and above the mixed
layer to compare measured concentrations at varying concentration levels. The flights will be
made downwind of urban areas in the mid-afternoon to increase the probability of encountering
elevated ozone and NOy concentrations.
The first four comparisons listed above will include comparisons of wind measurements.
These flights will involve a dog-leg pattern at at least one of the traverse altitudes in order to test
whether the aircraft indicate the same winds using the orthogonal components of their wind
measuring devices.
Comparison 1 will start from STI’s base at Santa Rosa Airport (STS). Comparisons 2
and 3 will start from the UCD’s base at University Airport (0O5) at Davis. Comparison 4 will
start at the DOE base at Fresno Yosemite International Airport (FAT). Comparison 5 will start
at the TVA base at Livermore (LVK). Before each flight the aircraft will meet at the starting
airports to synchronize data system clocks, compare GPS position readings, and to coordinate
flight plans among the pilots. The flights will include a spiral up from an airport to 5000 ft msl
or more with one following the other about 500 ft apart and a similar spiral back down to about
2000 ft msl or less. The flights will also include a traverse at 2000-3000 ft msl along a path to
intersect the local urban plume and a similar traverse at about 5000 ft msl or more. The aircraft
will fly the traverses side by side for at least 20 NM.
For comparisons 1 through 3, the aircraft will climb from their starting airports to 5500 ft
over University Airport. From there they will traverse side-by-side at 5500 ft msl to Sunset
Skyranch (Q40, 23 NM) and then to Auburn Airport (AUN, 35 NM). Over Auburn, they will
descend to 3000 ft msl, then traverse together at 3000 ft to Sunset Skyranch and then to
Sacramento Executive (SAC, 10 NM). Over Sacramento, they will descend and do a low pass
Chapter 2: FIELD MEASUREMENTS 2-73