HR: 0800h
AN: A41B-0034    [Abstracts]
TI: Airborne submillimeter measurements in the Arctic mid-winter 2004/2005 - Evidence for chlorine activation and denitrification
AU: * Kleinboehl, A
EM: Armin.Kleinboehl@jpl.nasa.gov
AF: Jet Propulsion Laboratory, Mail-Stop 183-501 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Bremer, H
EM: bremer@iup.physik.uni-bremen.de
AF: University of Bremen, P. O. Box 330 440, Bremen, 28334 Germany
AU: Kuellmann, H
EM: harry.kuellmann@iup.physik.uni-bremen.de
AF: University of Bremen, P. O. Box 330 440, Bremen, 28334 Germany
AU: Kuttippurath, J
EM: jaya@iup.physik.uni-bremen.de
AF: University of Bremen, P. O. Box 330 440, Bremen, 28334 Germany
AU: Browell, E V
EM: Edward.V.Browell@nasa.gov
AF: NASA Langley Research Center, Mail-Stop 401A, Hampton, VA 23681 United States
AU: Canty, T
EM: Timothy.Canty@jpl.nasa.gov
AF: Jet Propulsion Laboratory, Mail-Stop 183-501 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Salawitch, R J
EM: rjs@caesar.jpl.nasa.gov
AF: Jet Propulsion Laboratory, Mail-Stop 183-501 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Toon, G C
EM: toon@caesar.jpl.nasa.gov
AF: Jet Propulsion Laboratory, Mail-Stop 183-501 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Notholt, J
EM: jnotholt@iup.physik.uni-bremen.de
AF: University of Bremen, P. O. Box 330 440, Bremen, 28334 Germany
AB: We present measurements of stratospheric trace gases in the exceptionally cold Arctic vortex of late-January and early-February 2005. The measurements were obtained by the Airborne SUbmillimeter Radiometer ASUR during the Polar Aura Validation Experiment (PAVE). ASUR is a passive heterodyne radiometer operating in a frequency range between 604 and 662 GHz. In this frequency range spectral signatures of ozone, HCl, ClO, HNO3, N2O, and other trace gases can be found, from which vertical profiles can be retrieved. ASUR measurements during PAVE show large volume mixing ratios of ClO (up to ~1.7 ppb), indicating substantial chlorine activation up to an altitude of ~22 km inside the vortex. The distribution of HNO3 inside the vortex shows a considerable spatial variability, and reaches minima below 4 ppbv around 22 km altitude and maxima above 13 ppbv around 16 km altitude.We estimate denitrification inside the vortex and show that the HNO3 deficit is largest near the center of the vortex, where the airmasses had experienced temperatures below the NAT formation threshold for 80-100% of the previous 20 days according to back trajectories. This suggests that the main denitrification mechanism is based on sedimenting nitric acid trihydrate particles.
DE: 0340 Middle atmosphere: composition and chemistry
DE: 0341 Middle atmosphere: constituent transport and chemistry (3334)
DE: 3360 Remote sensing
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005