MIPAS observations of CFC trends
Alastair Burgess(1), R.G. Grainger(1) and A Dudhia(1)
(1) University of Oxford, Clarendon Laboratory, OX1 3PU, OXFORD, United Kingdom
MIPAS is a Fourier transform interferometer on Envisat, observing the infra-red thermal self-emission of the atmosphere.
We investigate the trend in the observed concentrations of CFC-11 (CCl3F) and CFC-12 (CCl2F2) throughout the life of the instrument. From September 2002 to March 2004, the nominal 'high resolution' (0.025cm-1) reprocessed L1B data is used. New work was performed to enable the use of the 'reduced resolution' (0.0625cm-1) data now being taken so the trend calculation could be extended to early 2006.
CFCs are implicated in the catalytic destruction of ozone and the polar 'ozone holes'. They are controlled by the Montreal protocol, and this work provides some means of quantifying its effect.
The long time series from a single satellite instrument is useful for tracking the evolution of the CFC stratospheric loading, and checking the accuracy of simulations.
The profiles of these species were determined using 'MORSE', developed at Oxford. It uses optimal estimation. Resulting profiles were combined a posteriori and three-day means calculated on a monthly basis. These means were used to determine the trends in various zonal latitude bands and the stratospheric chlorine loading.
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,