AN AUTOMATED-SYSTEM FOR THE MEASUREMENT OF NITROGEN-OXIDES AND OZONE CONCENTRATIONS FROM A PASSENGER AIRCRAFT - INSTRUMENTATION AND FIRST RESULTS OF THE NOXAR PROJECT

A fully automated system for measuring NO, NO2, and O-3 in the upper t roposphere and lower stratosphere from a passenger aircraft is describ ed. Detection limits (1 sigma) of 23, 45, and 500 pptv were achieved f or NO, NO2, and O-3, respectively, for a 2 min integration time during flights. Continuous measurements were made during a 1 year period end ing May 1996 on a total of 540 flights between Zurich and destinations in the United States and the Far East. The measurements represent abo ut a 10-fold increase in the coverage of presently available NOx measu rements in the tropopause region. The measurement hardware, based on c ommercially available instrumentation and specifically designed to mee t the very stringent safety regulations normal in civil aviation, is d escribed, and first results are briefly reported.