Longer-Term Trends Dian Seidel SPARC Temperature Trends Panel Meeting July 2006 Abingdon

Outline Datasets Considerations for our paper Recently published results Possible approaches for our paper

Datasets Radiosonde Rocketsonde (Chantal?) Berlin Analysis (Ulrike) Reanalysis (not considering)

Considerations Summarize published results and/or make new calculations? What can we learn (or report) that we didn’t know circa Ramaswamy et al. (Rev. Geophys. 2001)? –Effect of homogeneity adjustments on trends (Lanzante et al. 2003; Free et al., JGR 2005; Thorne et al., JGR 2005; CCSP 2006) –Time-segmented trends (Seidel and Lanzante, JGR 2004; Ramaswamy et al., Science 2006) –Details of volcanic signal (Free and Angell, JGR 2002; Santer et al., JGR 2001; above studies) –Statistical issues (Nishizawa and Yoden, JGR 2005) Use only homogeneity-adjusted datasets?

Radiosonde Datasets 1958-present (Update of 3/2005 Reading Report) Hadley Atmospheric Temperature (HadAT) –UK Met Office (Thorne et al. JGR 2005) –9 levels, including 300, 200, 150, 100, 50, and 30hPa –Gridded product –Adjustments based on Lanzante et al. (2003) and neighbor comparisons –Available now at Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC) –NOAA (Free et al. JGR 2005) –16 levels, including 300, 250, 200, 150, 100, 70, 50 and 30 hPa –Two datasets: Large-scale (~30 deg bands) anomaly time series based on Lanzante et al. (2003) adjustments through 1979, then first-difference method and metadata Station data with no adjustments post-1979, also 10-deg zonal data –Available now at

RATPAC and HadAT Coverage Source: CCSP report

Note great discrepancy between datasets in early years – RATPAC more variable, with larger Agung signal.

Temperature Trends in the Lower Atmosphere For further information on CCSP Synthesis and Assessment Product 1.1

Note good agreement between sonde (and surface) datasets compared with satellite.

Possible Approaches No discussion of pre-satellite errors –Pro: keeps paper shorter and more focused –Con: ignores developments with sonde data Text-only review of recent literature –Pro: addresses new developments without adding much length –Con: doesn’t allow presentation of new analysis Text-with-figure(s) presentation of some pre observations –Pro: most thorough approach –Cons: longer paper, more work