Precipitation response to regional radiative forcing NASA Goddard Institute for Space Studies and Columbia Earth Institute, New York, USA
02 Aug 2012
Received: 20 January 2012 – Published in Atmos. Chem. Phys. Discuss.: 13 February 2012 Abstract. Precipitation shifts can have large impacts on human society and ecosystems.
Many aspects of how inhomogeneous radiative forcings influence precipitation
remain unclear, however. Here we investigate regional precipitation responses
to various forcings imposed in different latitude bands in a climate model.
We find that several regions show strong, significant responses to most
forcings, but that the magnitude and even the sign depends upon the forcing
location and type. Aerosol and ozone forcings typically induce larger
responses than equivalent carbon dioxide (CO2) forcing, and the
influence of remote forcings often outweighs that of local forcings.
Consistent with this, ozone and especially aerosols contribute greatly to
precipitation changes over the Sahel and South and East Asia in historical
simulations, and inclusion of aerosols greatly increases the agreement with
observed trends in these areas, which cannot be attributed to either
greenhouse gases or natural forcings. Estimates of precipitation responses
derived from multiplying our Regional Precipitation Potentials (RPP; the
response per unit forcing relationships) by historical forcings typically
capture the actual response in full transient climate simulations fairly
well, suggesting that these relationships may provide useful metrics. The
strong sensitivity to aerosol and ozone forcing suggests that although some
air quality improvements may unmask greenhouse gas-induced warming,
they have large benefits for reducing regional disruption of the
Revised: 25 May 2012 – Accepted: 16 July 2012 – Published: 02 August 2012
Citation: Shindell, D. T., Voulgarakis, A., Faluvegi, G., and Milly, G.: Precipitation response to regional radiative forcing, Atmos. Chem. Phys., 12, 6969-6982, doi:10.5194/acp-12-6969-2012, 2012.