Download - Longer-Term Trends Dian Seidel SPARC Temperature Trends Panel Meeting 19-21 July 2006 Abingdon
Longer-Term Trends
Dian Seidel
SPARC Temperature Trends Panel Meeting
19-21 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 http://hadobs.metoffice.com/hadat/
• 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 http://www.ncdc.noaa.gov/oa/cab/ratpac/index.php
RATPAC and HadAT Coverage
Source: CCSP report
Source: CCSP reportNote 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
http://www.climatescience.gov/
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-1979 observations– Pro: most thorough approach– Cons: longer paper, more work