Engineering topics
Publications and source records attributed to Podolske, Jim R..
The wind and constituent measurements from the polar aircraft data are used to compute the flux spectra. Although there is variation from flight to flight, the flux spectra generally fit a -2 to -1.5 power law as expected theoretically. This result suggests that tracer fluxes from small scale features do not substantially contribute to the overall tracer budget relative to the fluxes from the larger scales.
Trend analysis of the Airborne Arctic Stratospheric Expedition's ER-2 profile data reveals an average decrease in N2O on potential temperature isentropes which can be attributed to diabatic cooling of inner vortex air. This conclusion is independently supported by radiative transfer computations. Trends in ozone and water vapor over the same period are not consistent with the magnitude of the diabatic descent. After accounting for the diabatic motion (estimated from N2O), an additional 0.44 + or - 0.3 percent/day average anomalous O3 decrease above 440 K (about 20 km) is needed to balance the continuity equation. This ozone decrease suggests additional photochemical destruction of ozone in the presence of the high amounts of ClO observed during the mission. A 0.4 + or - 0.3 percent/day average anomalous increase in H2O is also observed near 420 K (about 18 km) which may be due to the evaporation of ice crystals falling from higher, colder stratospheric layers.
Measurements of N2O and O3 during the Airborne Arctic Stratospheric Expedition have been composited using the potential vorticity and potential temperature of each measurement as coordinates. For ozone, data sources included the ER-2 and balloon ozonesonde in situ measurements, DC-8 DIAL lidar, and Stratospheric Aerosol and Gas Experiment satellite profiles. For N2O, only ER-2 data were used. These chemical composites have been reconstructed onto average meteorological fields for the mission in a latitude-altitude cross section, yielding a picture of the chemical composition of the polar vortex during this period. Tracers inside the vortex show an apparent descent of about 2 km relative to those outside, resulting in an apparent chemical edge on isentropic and isobaric surfaces.