Emmert et al. (2008)
Also: Emmert et al. 2007
Thermospheric global average density trends, 1967-2007, derived from orbits of 5000 near‐Earth objects
Emmert, J. T., Picone, J. M., & Meier, R. R. (2008). Thermospheric global average density trends, 1967-2007, derived from orbits of 5000 near‐Earth objects. Geophysical Research Letters, 35(5). Link to PDF
References
All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.