AIRCRAFT-BORNE DETECTION OF STRATOSPHERIC COLUMN AMOUNTS OF O-3, NO2,OCLO2 CLNO3, HNO3, AND AEROSOLS AROUND THE ARCTIC VORTEX (79-DEGREES-N TO 39-DEGREES-N) DURING SPRING 1993 .1. OBSERVATIONAL DATA

Using several remote sensing techniques on board a research aircraft ( Transall C-160), we measured the stratospheric column amounts of O-3, NO2, OClO, ClNO3, and HNO3, and the height-resolved aerosol backscatte ring ratios during March 7-10, 1993. During this period the polar vort ex extended from the Arctic well into the Mediterranean (35 degrees N) . Several underflights of the vortex and its edge region were conducte d, covering Arctic (79 degrees N) to Mediterranean latitudes (39 degre es N). During all the flights, moderate amounts of NO2 (0.7-2 . 10(15) /cm(2)), elevated amounts of HNO3 (1.75-2.35 . 10(16)/cm(2)), ClNO3 (2 .4-5.4 . 10(15)/cm(2)),and OClO (6-13 . 10(12)/cm(2)) were found insid e the vortex, indicating that the air masses of the vortex were still chemically disturbed. The observation is interpreted as the polar vort ex going from the stage of its wintertime denoxification (conversion o f NOx into NOy) and chlorine activation (conversion of HCl and ClNO3 i nto chlorine oxides) to the springtime reverse processes via the forma tion of enhanced amounts of ClNO3. In addition, first measurements of OClO (6.10(12)/cm(2) at solar zenith angle 90 degrees) and high amount s of ClNO3 (4.10(15)/cm(2)) around 40 degrees N are reported.