Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Effects of orbital decay on satellite-derived lower-tropospheric temperature trends


The 17-year lower-tropospheric temperature record derived from the satellite Microwave Sounding Unit (MSU)1,2,3 shows a global cooling trend, from 1979 to 1995, of −0.05 K per decade at an altitude of about 3.5 km (refs 4, 5). Air temperatures measured at the Earth's surface, in contrast, have risen by approximately +0.13 K per decade over the same period4,6. The two temperature records are derived from measurements of different physical parameters, and thus are not directly comparable. In fact, the lower stratosphere is cooling substantially (by about −0.5 K per decade)5, so the warming trend seen at the surface is expected to diminish with altitude and change into a cooling trend at some point in the troposphere. Even so, it has been suggested that the cooling trend seen in the satellite data is excessive4,7,8. The difficulty in reconciling the information from these different sources has sparked a debate in the climate community about possible instrumental problems and the existence of global warming4,7,9. Here we identify an artificial cooling trend in the satellite-derived temperature series caused by previously neglected orbital-decay effects. We find a new, corrected estimate of +0.07 K per decade for the MSU-based temperature trend, which is in closer agreement with surface temperatures. We also find that the reported7 cooling of the lower troposphere, relative to the middle troposphere, is another artefact caused by uncorrected orbital-decay effects.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout

Figure 1: Cumulative orbital decays for NOAA satellites from 1979 to 1996.
Figure 2: Effect of correction for orbital decay on MSU2R lower-tropospheric temperature anomalies.

Similar content being viewed by others


  1. Spencer, R. W. & Christy, J. R. Precise monitoring of global temperature trends from satellites. Science 247, 1558–1562 (1990).

    Article  ADS  CAS  Google Scholar 

  2. Spencer, R. W. & Christy, J. R. Precision and radiosonde validation of satellite gridpoint temperature anomalies. Part II: A tropospheric retrieval and trends during 1979–90. J. Clim. 5, 858–866 (1992).

    Article  ADS  Google Scholar 

  3. Christy, J. R. & McNider, R. T. Satellite greenhouse signal. Nature 367, 325 (1994).

    Article  ADS  Google Scholar 

  4. Hurrell, J. W. & Trenberth, K. E. Difficulties in obtaining reliable temperature trends: Reconciling the surface and satellite MSU2R trends. J. Clim.(in the press).

  5. Houghton, J. T. et al. (eds) Climate Change 1995: The Science of Climate Change (Cambridge Univ. Press, (1996)).

    Google Scholar 

  6. Jones, P. D. Recent warming in global temperature series. Geophys. Res. Lett. 21, 1149–1152 (1994).

    Article  ADS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  Google Scholar 

  9. Christy, J. R., Spencer, R. W. & Braswell, W. D. How accurate are satellite ‘thermometers’? Nature 389, 342–342 (1997).

    Article  ADS  CAS  Google Scholar 

  10. Hansen, J. et al. Forcings and chaos in interannual to decadal climate change. J. Geophys. Res. 102, 25679–25720 (1997).

    Article  ADS  CAS  Google Scholar 

  11. Willson, R. C. Total solar irradiance trend during solar cycles 21 and 22. Science 277, 1963–1965 (1997).

    Article  ADS  CAS  Google Scholar 

  12. Wentz, F. J. Awell-calibrated ocean algorithm for special sensor microwave/imager. J. Geophys. Res. 102, 8703–8718 (1997).

    Article  ADS  Google Scholar 

  13. Liebe, H. J. An updated model for millimeter wave propagation in moist air. Radio Sci. 20, 1069–1089 (1985).

    Article  ADS  Google Scholar 

  14. Gaffen, D. Temporal inhomogeneities in radiosonde temperature records. J. Geophys. Res. 99, 3667–3676 (1994).

    Article  ADS  Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to Frank J. Wentz.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

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

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing