Stratospheric meteorological conditions for the 3-12 Nov 1994 ATMOS/ATLAS-3 measurements

During the ATLAS-3 mission (3-12 Nov 1994), United Kingdom Meteorological Office fields show that the SH vortex was still strong below about 700 K (similar to 16 hPa), with coherent vortex fragments apparent up to about 1300 K (similar to 3 hPa). The SH vortex was shifted off the pole toward 270 degrees E throughout ATLAS-3, although its shape varied from day to day. SH temperatures were increasing during ATLAS-3; temperatures below 188 K were last seen 35-45 days before the mission, but were below 195 K as late as 2 Nov 1994. The NH polar vortex had developed at levels above about 550 K (similar to 35 hPa). Simulated high-resolution potential vorticity (PV) fields clearly show low latitude air being drawn up around the polar vortices in both hemispheres. These fields indicate that meteorological analyses underestimate the amount of atmospheric variability, including the strength of local PV gradients, and small-scale structure Structure such as that in the simulated fields can result in apparent discrepancies between tracer measurements and PV fields.