Chemical ozone loss in the Arctic vortex in the winter 1995-96: HALOE measurements in conjunction with other observations

Severe chemical ozone loss has been detected in the Arctic in the winter an d spring of 1995-96 by a variety of methods. Extreme reductions in column o zone due to halogen catalysed chemistry were derived from measurements of t he Halogen Occultation Experiment (HALOE) on board the Upper Atmosphere Res earch Satellite in the Arctic vortex. Here, we discuss further aspects of t he HALOE observations in the Arctic over this period. Potential problems, b oth in the data themselves and in the methodology of the data analysis are considered and the reason for the differences between the Arctic ozone loss es deduced from HALOE data version 17 and 18 is analysed. Moreover, it is s hown that HALOE measurements in the Arctic in winter and spring 1995-96 com pare well with observations by other ground-based and satellite instruments .