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Long-Term Stratospheric Temperature Time Series for SPARC Temperature Trends Assessment Paper. Dian Seidel 12-13 April 2007 Tabard Inn, Washington DC. 4 Radiosonde Datasets 1958-2005. RATPAC (large-scale zonal time series, homogeneity adjusted) HadAT (gridded, homogeneity adjusted)
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Long-Term Stratospheric Temperature Time Series for SPARC Temperature Trends Assessment Paper Dian Seidel 12-13 April 2007 Tabard Inn, Washington DC
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
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
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
Extra Plots • Trend comparison for 1965-2001 • Effect of time series normalization on FUB data • More time series