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Contribution of stratospheric cooling to satellite-inferred tropospheric temperature trends


From 1979 to 2001, temperatures observed globally by the mid-tropospheric channel of the satellite-borne Microwave Sounding Unit (MSU channel 2), as well as the inferred temperatures in the lower troposphere, show only small warming trends of less than 0.1 K per decade (refs 1–3). Surface temperatures based on in situ observations however, exhibit a larger warming of 0.17 K per decade (refs 4, 5), and global climate models forced by combined anthropogenic and natural factors project an increase in tropospheric temperatures that is somewhat larger than the surface temperature increase6,7,8. Here we show that trends in MSU channel 2 temperatures are weak because the instrument partly records stratospheric temperatures whose large cooling trend9 offsets the contributions of tropospheric warming. We quantify the stratospheric contribution to MSU channel 2 temperatures using MSU channel 4, which records only stratospheric temperatures. The resulting trend of reconstructed tropospheric temperatures from satellite data is physically consistent with the observed surface temperature trend. For the tropics, the tropospheric warming is 1.6 times the surface warming, as expected for a moist adiabatic lapse rate.

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  1. 1

    Christy, J. R. et al. Error estimates of version 5.0 of MSU-AMSU bulk atmospheric temperatures. J. Atmos. Ocean. Technol. 20, 613–629 (2003)

  2. 2

    Mears, C. A., Schabel, M. C. & Wentz, F. J. A reanalysis of the MSU channel 2 tropospheric temperature record. J. Clim. 16, 3650–3664 (2003)

  3. 3

    Seidel, D. J. et al. Uncertainty in signals of large-scale climate variations in radiosonde and satellite upper-air temperature datasets. J. Clim. (in the press)

  4. 4

    Houghton, J. T. et al. in Climate Change 2001: The Scientific Basis (Cambridge Univ. Press, London, 2001)

  5. 5

    Jones, P. D. & Moberg, A. Hemispheric and large-scale surface air temperature variations: An extensive revision and an update to 2001. J. Clim. 16, 206–223 (2003)

  6. 6

    Bengtsson, L., Roeckner, E. & Stendel, M. Why is the global warming proceeding much slower than expected? J. Geophys. Res. 104, 3865–3876 (1999)

  7. 7

    Santer, B. D. et al. Interpreting differential temperature trends at the surface and in the lower troposphere. Science 287, 1227–1232 (2000)

  8. 8

    Hansen, J. et al. Climate forcings in Goddard Institute for Space Studies SI2000 simulations. J. Geophys. Res. 107, doi:10.1029/2001JD001143 (2002)

  9. 9

    Ramaswamy, V. et al. Stratospheric temperature trends: Observations and model simulations. Rev. Geophys. 39, 71–122 (2001)

  10. 10

    Spencer, R. W. & Christy, J. R. Precise monitoring of global temperature trends from satellites. Science 247, 1558–1662 (1990)

  11. 11

    Hansen, J. et al. Satellite and surface temperature data at odds? Clim. Change 30, 103–117 (1995)

  12. 12

    Wallace, J. M. et al. Reconciling Observations of Global Temperature Change (National Academy Press, Washington DC, 2000)

  13. 13

    Singer, S. F. Difficulty in reconciling global warming data. Nature 409, 281 (2001)

  14. 14

    Hegerl, G. C. & Wallace, J. M. Influence of patterns of climate variability on the difference between satellite and surface temperature trends. J. Clim. 15, 2412–2428 (2002)

  15. 15

    Santer, B. D. et al. Influence of satellite data uncertainties on the detection of externally forced climate change. Science 300, 1280–1284 (2003)

  16. 16

    Gaffen, D. J., Sargent, M. A., Habermann, R. E. & Lanzante, J. R. Sensitivity of tropospheric and stratospheric temperature trends to radiosonde data quality. J. Clim. 13, 1776–1796 (2000)

  17. 17

    Lanzante, J. R., Klein, S. A. & Seidel, D. J. Temporal homogenization of monthly radiosonde temperature data. J. Clim. 16, 224–262 (2003)

  18. 18

    Christy, J. R., Spencer, R. W. & McNider, R. T. Reducing noise in the MSU daily lower-tropospheric global temperature dataset. J. Clim. 8, 888–896 (1995)

  19. 19

    Christy, J. R., Spencer, R. W. & Lobl, E. S. Analysis of the merging procedure for the MSU daily temperature time series. J. Clim. 11, 2016–2041 (1998)

  20. 20

    Wentz, F. J. & Schabel, M. Effects of orbital decay on satellite-derived lower-tropospheric temperature trends. Nature 394, 661–664 (1998)

  21. 21

    Christy, J. R., Spencer, R. W. & Braswell, W. D. MSU tropospheric temperature: Dataset construction and radiosonde comparisons. J. Atmos. Ocean. Technol. 17, 1153–1170 (2000)

  22. 22

    Prabhakara, C., Iacovazzi, J. R., Yoo, J. M. & Dalu, G. Global warming: Evidence from satellite observations. Geophys. Res. Lett. 27, 3517–3520 (2000)

  23. 23

    Mo, T., Goldberg, M. D. & Crosby, D. S. Recalibration of the NOAA microwave sounding unit. J. Geophys. Res. 106, 10145–10150 (2001)

  24. 24

    Vinnikov, K. Y. & Grody, N. C. Global warming trend of mean tropospheric temperature observed by satellites. Science 302, 269–272 (2003)

  25. 25

    Spencer, R. W. & Christy, J. R. Precision and radiosonde validation of satellite gridpoint temperature anomalies. Part II: A tropospheric retrieval and trends during 1979–1990. J. Clim. 5, 858–866 (1992)

  26. 26

    Hurrell, J. W. & Trenberth, K. E. Spurious trends in satellite MSU temperature from merging different satellite records. Nature 386, 164–167 (1997)

  27. 27

    Trenberth, K. E. & Hurrell, J. W. Reply to “How accurate are satellite ‘thermometers’?”. Nature 389, 342–343 (1997)

  28. 28

    Hurrell, J. W. & Trenberth, K. E. Difficulties in obtaining reliable temperature trends: Reconciling the surface and satellite Microwave Sounding Unit records. J. Clim. 11, 945–967 (1998)

  29. 29

    Stone, P. H. & Carlson, J. H. Thermal equilibrium of the atmosphere with a given distribution of relative humidity. J. Atmos. Sci. 36, 415–423 (1979)

  30. 30

    Wentz, F. J. & Schabel, M. Precise climate monitoring using complementary satellite data sets. Nature 403, 414–416 (2000)

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We thank J. M. Wallace for discussions. We also thank J. M. Wallace, D. L. Hartmann, J. R. Holton, J. K. Angell and M. Free for their comments on the manuscript. This study was supported by the US DOE, NSF and NASA.

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Competing interests

The authors declare that they have no competing financial interests.

Correspondence to Qiang Fu.

Supplementary information

Supplementary Discussion

Supplementary Table 1: Coefficients in Equation (1); Supplementary Fig.1. Comparison of monthly mean, global-average temperature anomaly time series; Supplementary Table 2: Atmospheric temperature trends shown in Fig.3 with 95% confidence intervals (K/decade). (PDF 64 kb)

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Further reading

Figure 1: Atmospheric weighting functions and brightness temperature responses.
Figure 2: Time series of monthly mean, global-average temperature anomalies.
Figure 3: Trends in monthly mean temperature anomalies.


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