Evaluation of Lower Stratosphere Temperatures in Reanalyses in the Southern High Latitudes

Lower stratospheric temperatures over Antarctica are a key diagnostic to relate the thermal-chemical reactions that occur during the springtime depletion of ozone in that part of the atmosphere. As ozone depleting substances (ODS) gradually diminish, it is expected that the amount of ozone depleted during the austral spring will decrease over the next half century. The extreme interannual variability of meteorological conditions over the southern high latitudes and their impact upon how much ozone is depleted makes it difficult to confidently determine if a trend in smaller ozone holes has occurred. Temperatures from reanalyses are used to assess the long term thermal conditions over Antarctica during the austral spring. Unfortunately, there is quite a large variance in the analyzed lower stratosphere temperatures from the more recent reanalyses during the 1979-1998 period. A comparison of the more recent reanalyses will be presented along with differences from Antarctica radiosondes to determine the amount of error in the lower stratosphere temperatures.