FINE-SCALE, POLEWARD TRANSPORT OF TROPICAL AIR DURING AASE-2

The poleward transport of tropical air in the lower stratosphere durin g the winter period of the second Airborne Arctic Stratospheric Expedi tion (December 1991 - March 1992) is examined using contour advection calculations. These calculations show that filaments of tropical air e xtend into mid-latitudes, and are wrapped around the equatorward edge of the polar jet. Simultaneously filaments are drawn from the polar vo rtex and are intermingled with the filaments of tropical air. The trop ical filaments are consistent with measurements of chemical tracers ta ken aboard the ER-2 and DC-8 aircraft which show localized regions, in mid-latitudes, of air with the characteristics of tropical air.