A study of polar ozone depletion based on sequential assimilation of satellite data from the ENVISAT/MIPAS and Odin/SMR instruments J. D. Rösevall, D. P. Murtagh, J. Urban, and A. K. Jones Department of Radio & Space Science, Chalmers Univ. of Technology, Göteborg, Sweden
Abstract. The objective of this study is to demonstrate how polar ozone depletion can
be mapped and quantified by assimilating ozone data from satellites into the
wind driven transport model DIAMOND, (Dynamical Isentropic Assimilation Model
for OdiN Data). By assimilating a large set of satellite data into a
transport model, ozone fields can be built up that are less noisy than the
individual satellite ozone profiles. The transported fields can subsequently
be compared to later sets of incoming satellite data so that the rates and
geographical distribution of ozone depletion can be determined. By tracing
the amounts of solar irradiation received by different air parcels in a
transport model it is furthermore possible to study the photolytic reactions
that destroy ozone.
In this study, destruction of ozone that took place in the Antarctic winter
of 2003 and in the Arctic winter of 2002/2003 have been examined by
assimilating ozone data from the ENVISAT/MIPAS and Odin/SMR
satellite-instruments. Large scale depletion of ozone was observed in the
Antarctic polar vortex of 2003 when sunlight returned after the polar night.
By mid October ENVISAT/MIPAS data indicate vortex ozone depletion in the
ranges 80–100% and 70–90% on the 425 and 475 K potential temperature
levels respectively while the Odin/SMR data indicates depletion in the ranges
70–90% and 50–70%. The discrepancy between the two instruments has been
attributed to systematic errors in the Odin/SMR data.
Assimilated fields of ENVISAT/MIPAS data indicate ozone depletion in the
range 10–20% on the 475 K potential temperature level, (~19 km
altitude), in the central regions of the 2002/2003 Arctic polar vortex.
Assimilated fields of Odin/SMR data on the other hand indicate ozone
depletion in the range 20–30%.
Citation: Rösevall, J. D., Murtagh, D. P., Urban, J., and Jones, A. K.: A study of polar ozone depletion based on sequential assimilation of satellite data from the ENVISAT/MIPAS and Odin/SMR instruments, Atmos. Chem. Phys., 7, 899-911, doi:10.5194/acp-7-899-2007, 2007.