Land use change suppresses precipitation 1Forschungszentrum Karlsruhe, IMK-IFU, Garmisch-Partenkirchen, Germany
2Airborne Research Australia, Flinders University, Adelaide, Australia
3Murdoch University, Perth, Australia
4National Space Science Technology Center, Huntsville, Alabama, USA
Received: 14 April 2009 – Published in Atmos. Chem. Phys. Discuss.: 08 May 2009 Abstract. A feedback loop between regional scale deforestation and climate change was
investigated in an experiment using novel, small size airborne platforms and
instrument setups. Experiments were performed in a worldwide unique natural
laboratory in Western Australia, characterized by two adjacent homogeneous
observation areas with distinctly different land use characteristics.
Conversion of several ten thousand square km of forests into agricultural
land began more than a century ago. Changes in albedo, surface roughness,
the soil water budget and the planetary boundary layer evolved over decades.
Besides different meteorology, we found a significant up to now overlooked
source of aerosol over the agriculture area. The enhanced number of cloud
condensation nuclei is coupled through the hydrological groundwater cycle
with deforestation. Modification of surface properties and aerosol number
concentrations are key factors for the observed reduction of precipitation.
The results document the importance of aerosol indirect effects on climate
due to nanometer size biogenic aerosol and human impact on aerosol sources.
Revised: 13 August 2009 – Accepted: 15 August 2009 – Published: 10 September 2009
Citation: Junkermann, W., Hacker, J., Lyons, T., and Nair, U.: Land use change suppresses precipitation, Atmos. Chem. Phys., 9, 6531-6539, doi:10.5194/acp-9-6531-2009, 2009.