Atmos. Chem. Phys. Discuss., 11, 9375-9405, 2011
www.atmos-chem-phys-discuss.net/11/9375/2011/
doi:10.5194/acpd-11-9375-2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Global precipitation response to changing external forcings since 1870
A. Bichet, M. Wild, D. Folini, and C. Schär
Institute for Atmospheric and Climate Sciences, ETH Zürich, Switzerland

Abstract. Predicting and adapting to changes in the hydrological cycle is one of the major challenges for the twenty-first century. To better estimate how it will respond to future changes in climate forcings, it is crucial to understand how it has evolved in the past and why. In our study, we use an atmospheric global climate model with prescribed sea surface temperatures (SSTs) to investigate how changing external climate forcings have affected global land temperature and precipitation in the period 1870–2005. We show that prescribed SSTs (encapsulating other forcings) are the dominant forcing driving the decadal variability of land temperature and precipitation since 1870. On top of this SSTs forcing, we also find that the atmosphere-only response to increasing aerosol emissions is a reduction in global land temperature and precipitation by up to 0.4 °C and 30 mm year−1, respectively, between about 1930 and 2000. Similarly, the atmosphere-only response to increasing greenhouse gas concentrations is an increase in global land temperature and precipitation by up to 0.25 °C and 10 mm year−1, respectively, between about 1950 and 2000. Finally, our results also suggest that between about 1950 and 1970, increasing aerosol emissions had a larger impact on the hydrological cycle than increasing greenhouse gases concentrations.

Citation: Bichet, A., Wild, M., Folini, D., and Schär, C.: Global precipitation response to changing external forcings since 1870, Atmos. Chem. Phys. Discuss., 11, 9375-9405, doi:10.5194/acpd-11-9375-2011, 2011.
 
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