An observationally based constraint on the water-vapor feedback
| Autor: | Alexandra Jonko, Karen M. Shell, Piers M. Forster, N. D. Gordon |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Atmospheric Science
010504 meteorology & atmospheric sciences Meteorology Global warming Forcing (mathematics) 010502 geochemistry & geophysics Atmospheric sciences 7. Clean energy 01 natural sciences Cloud feedback Geophysics 13. Climate action Space and Planetary Science Atmospheric Infrared Sounder Earth and Planetary Sciences (miscellaneous) Radiative transfer Environmental science Climate model Water vapor 0105 earth and related environmental sciences Positive feedback |
| Zdroj: | Journal of Geophysical Research: Atmospheres. 118:12-12,443 |
| ISSN: | 2169-897X |
| DOI: | 10.1002/2013jd020184 |
| Popis: | [1] The increase in atmospheric concentrations of water vapor with global warming is a large positive feedback in the climate system. Thus, even relatively small errors in its magnitude can lead to large uncertainties in predicting climate response to anthropogenic forcing. This study incorporates observed variability of water vapor over 2002–2009 from the Atmospheric Infrared Sounder instrument into a radiative transfer scheme to provide constraints on this feedback. We derive a short-term water vapor feedback of 2.2 ± 0.4 Wm−2K−1. Based on the relationship between feedback derived over short and long timescales in twentieth century simulations of 14 climate models, we estimate a range of likely values for the long-term twentieth century water vapor feedback of 1.9 to 2.8 Wm−2K−1. We use the twentieth century simulations to determine the record length necessary for the short-term feedback to approach the long-term value. In most of the climate models we analyze, the short-term feedback converges to within 15% of its long-term value after 25 years, implying that a longer observational record is necessary to accurately estimate the water vapor feedback. |
| Databáze: | OpenAIRE |
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