Recent Results from Radiosondes and Other Observing Systems

1. Recent Results from Radiosondes and Other Observing Systems Dian Seidel NOAA Air Resources Lab. Silver Spring, MD Workshop on Vertical Temperature Changes, Asheville, NC, 27-29 October 2003

2. Topics • Characterizing atmospheric temperature changes • New NOAA radiosonde datasets • Intercomparison of satellite and radiosonde datasets • Removing the stratospheric signal from MSU2 data • High elevation, surface, and free-air temperatures • Integrating proxies for tropospheric temperature

3. Characterizing atmospheric temperature changes • Linear trends are simplistic descriptors of temperature change • Some temperature changes appear to be abrupt • “Slopes and steps” models are almost as simple, but better characterize the data • Quantitative temperature changes are very sensitive to the statistical model chosen

4. Data sources: GHCN and UEA

5. Data sources: HadRT2.1s and LKS

6. Data sources: UAH ver. 5.0 and RSS

7. New NOAA radiosonde datasets • 54-station network (Angell, J. Climate, 2003) • Adjusted LKS 87-station network (Lanzante, Klein, Seidel, J. Climate, 2003) • RATPAC – radiosonde atmospheric temperature products for assessing climate (not yet avail.)

8. Angell’s 63-to-54-station network

9. Identification of anomalous stations

10. Effect of removing 9 stations

11. Lanzante-Klein-Seidel 87-station network

12. Sensitivity of trends to LKS adjustments (solid)blue 30-90Ngreen 30N-30Sred 30-90S

13. NOAA RATPAC • ARL/GFDL/NCDC collaboration, supported by OGP/CCDD • Uses LKS data as a core • Network expansion would introduce more uncertainty • Extends beyond 1997 using first difference method and postCARDS data • Relies on station history metadata to identify break points

14. Intercomparison of satellite and radiosonde datasets Seidel, Angell, Christy, Free, Klein, Lanzante, Mears, Parker, Schabel, Spencer, Sterin, Thorne, and Wentz (submitted to J. Climate)

18. Signals of large-scale climate variations

22. Removing the stratospheric signal from MSU2 data • Qiang Fu, Celeste Johanson, Steve Warren, Dian Seidel • Submitted, do not cite • qfu@atmos.washington.edu

23. High elevation, surface, and free-air temperatures • Motivated partly by observations of recent rapid glacial retreat • Seidel and Free (Climatic Change, 2003) • Pepin and Losleben (Intl. J. Clim., 2002) • Climatic Change, 2003. Special Issue edited by H. Diaz

24. Mountain Ranges Sampled by Paired Radiosonde Sites

27. Ongoing work by Pepin incorporates surface station data and upper air data from radiosondes and reanalysis • Glacial retreat, especially in tropics, may be more influenced by hydrologic changes than warming.

28. Integrating proxies for tropospheric temperature • Total column water vapor (Wentz and Schabel, Nature, 2000) • Tropopause height and pressure, particularly in the tropics (Randel et al., JGR, 2000; Seidel et al., JGR, 2001; Santer et al., JGR, 2003) • Polar vortex (Frauenfeld and Davis, JGR, 2003; Angell, JGR, 2001) • Others?

29. 1.5 1.0 0.5 Departure 0 -0.5 -1.0 300 hPa Center Contour Midlatitude MSU 2LT -1.5 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001

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