Jul 25, 2003
Contributions of Anthropogenic and Natural Forcing to Recent Tropopause Height Changes
by
,
Science
- Observations indicate that the height of the tropopause—the boundary between the stratosphere and troposphere—has increased by several hundred meters since 1979
- Comparable increases are evident in climate model experiments, which show that human-induced changes in ozone and well-mixed greenhouse gases account for ∼80% of the simulated rise in tropopause height over 1979–1999
- Their primary contributions are through cooling of the stratosphere (caused by ozone) and warming of the troposphere (caused by well-mixed greenhouse gases)
- Finds that a model-predicted fingerprint of tropopause height changes is statistically detectable in two different observational (“reanalysis”) data sets
- Concludes that this positive detection result allows us to attribute overall tropopause height changes to a combination of anthropogenic and natural external forcings, with the anthropogenic component predominating