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Polar Atmospheric Chemistry at the Tropopause (PACT)

Polar Atmospheric Chemistry at the Tropopause (PACT) aims to improve understanding of the distribution and variability of ozone in the polar upper troposphere – lower stratosphere (UTLS) region and the feedbacks of ozone changes to polar climate. 

Recently PACT work as focussed on finalising a database on tropopause region parameters that is being derived using all available ozonesonde measurements poleward of 50° latitude. The ozonesonde data have been obtained from the World Ozone and Ultraviolet Radiation Data Centre (WOUDC;, the Network for the Detection of Atmospheric Composition Change (NDACC; and the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory ( The earliest data currently used are from Syowa in Antarctica (1966), although the majority of information comes from the 1990s and later years.

Documentation and data are available from the PACT web site at the Australian Antarctic Data Centre Data Centre (

Scientific Committee on Antarctic Research
c/o Scott Polar Research Institute
University of Cambridge
Lensfield Road
Cambridge, CB2 1ER, United Kingdom
Tel: +44 1223 336550