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A critical unanswered question in polar studies is the consistency of evolving tracer fields with constituent fields (e.g., O3 and NOy) prior to precipitous changes initiated by phase transitions (formation of PSC I and PSC II regions) and chemical catalysis, both heterogeneous and homogeneous. This demands detailed coverage, at high spatial resolution from the poleward edge of the subtropical jet (≈40°) to the pole and from just below the tropopause to 30 km.

This series of experiments will first establish the relationship between the major tracers (N2O, CH4, CFC-11) and the ozone field. Does the regression of O3 against each of the tracers establish a consistent picture? Does the relationship between potential vorticity and N2O substantiate the current conception that they are surrogates for each other?

Perhaps the most critical advance from this analysis, however, will be a mapping of ozone redistribution resulting from the motion of the atmosphere per se. This will be extracted from maps of zonally averaged meridional/subsidence defined by the evolving relationship between tracers and pressure surfaces.

Stratospheric warmings, particularly in the northern hemisphere, have a dramatic effect on the PV, θ, N2O, CH4, CFC-11, H2O, and O3 fields. These events will be characterized for the first time with unmanned aircraft because the length scales of interest range from 0.1 km to 100 km, a regime inaccessible to any other technology.

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The regions of broadly distributed low temperature develop first in the vicinity of 20-25 km. They are highly localized and, in their initial stages, go undetected at spatial resolutions of 0.1 km and greater. As the vortex evolves through the winter, these PSC regions spread horizontally and downward, typically moving down to ER-2 altitudes (19 km) in their latter stages. Growth of ice-Nitric acid trihydrate (PSC II) particles to sizes 1-3 μ also redistributes NOy by particle subsidence. Thus, it is critical to observe the evolution of the system from the threshold conditions to a fully mature, chemically perturbed vortex.

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