There is a new paper which confirms this finding that changes in time in the vertical redistribution of heat makes a significant difference to long term trends in minimum temperatures.
This paper is Zhou, Liming, Yuhong Tian, Somnath Baidya Roy, Chris Thorncroft, Lance F. Bosart and Yuanlong Hu 2012: Impacts of wind farms on land surface temperature. Nature Climate Chnage. doi:10.1038/nclimate1505
