1. Long-Term Stratospheric Temperature Time Series for SPARC Temperature Trends Assessment Paper Dian Seidel 12-13 April 2007 Tabard Inn, Washington DC

2. 4 Radiosonde Datasets 1958-2005 RATPAC (large-scale zonal time series, homogeneity adjusted) HadAT (gridded, homogeneity adjusted) Randel and Wu (RATPAC-based, with further homogeneity adjustments) FUB – gridded analyses, 0-90N, no adjustments, available only for 1964-2001

3. Comparison 5 levels (100, 70, 50, 30, and 100-50 hPa) 16 zonal regions (0-20, 0-30, 0-90, 30-60,30-90, 60-90 for both hemispheres, plus 90S-90N, 20S- 20N, and 30S-30N Seasonal anomaly time series, normalized to 1965-1985 base period Annual difference (from RATPAC) time series Trends computed for individual time series and difference series

4. Summary Points (none too surprising) better agreement in NH than SH better agreement at lower altitudes than higher generally less cooling in Randel and Wu than RATPAC (although not in NH extratropics) HadAT generally cools more than RATPAC, but there are plenty of exceptions when HadAT cools less FUB generally cools more than any of the other three more uncertainty in trends above 100 mb than at 100 mb annual anomaly differences among datasets can be ± 1 K globally and in NH, ± several K in tropics and SH

8. Extra Plots Trend comparison for 1965-2001 Effect of time series normalization on FUB data More time series