We have a new paper accepted which provides further observational verification of the important role of land use on weather. It is
Nair, U.S., Y. Wu, J. Kala, T. J. Lyons, R.A. Pielke Sr., and J.M. Hacker, 2010: The role of land use change on the development and evolution of the West Coast trough, convective clouds, and precipitation in Southwest Australia. J. Geophys. Res.-Atmos., in press.
The abstract reads
Land clearing for agricultural purposes in southwest Australia has created a landscape where a 750 km rabbit-proof fence separates 13 million hectares of croplands from the remnant native vegetation to the east. The Bunny Fence Experiment (BuFex) was conducted in the vicinity of the intended vermin-proof boundary in December 2005 and August 2007. The experiment examined the role of land cover change (LCC) on the preferential formation of clouds over the native vegetation that often terminates along the vermin-proof fence as well as the regional rainfall reduction observed in this region. Observations and numerical model analysis show that the formation and development of the west coast trough (WCT), which is a synoptic-scale feature that initiates spring and summertime convection, is impacted by land cover change and that the cloud fields induced by the WCT would extend further west in the absence of the LCC. The surface convergence patterns associated with the wintertime WCT circulation is substantially altered by LCC, due to changes in both WCT dynamics and surface aerodynamic roughness, leading to a rainfall decrease to the west of the rabbit fence. It is found that the LCC in southwest Australia is indeed responsible for preferential formation of clouds over native vegetation and contributes to the observed rainfall reduction in this region.”
The conclusion contains the text
“This study further confirms the strong influence of landscape on weather and climate that has been also found in other studies [e.g., NRC, 2005; Kabat et al., 2004; Pielke et al., 2007]. The influence of vegetation and its change over time due to human management activities needs to be included in assessments of climate variability and change.”