The Variation of Near-Surface Wind Speed with Altitude of Land
McVicar, T.R., Van Niel, T.G., Roderick, M.L., Li, L.T., Mo, X.G., Zimmermann, N.E. and Schmatz, D.R. 2010. Observational evidence from two mountainous regions that near-surface wind speeds are declining more rapidly at higher elevations than lower elevations: 1960-2006. Geophysical Research Letters 37: 10.1029/2009GL042255.
Defining uz as change in wind speed with change in elevation -- uz = Δu/Δz, where Δu = u2-u1, Δz = z2-z1, and z2 > z1 -- McVicar et al. calculated monthly averages of uz based on monthly average u data from low-set (10-meter) anemometers maintained by the Chinese Bureau of Meteorology at 82 sites in central China and by MeteoSwiss at 37 sites in Switzerland from January 1960 through December 2006, which activity, in their words, constituted "the first time that long-term trends in uz in mountainous regions have been calculated." In doing so, the seven scientists determined that "for both regions uz trend results showed that u has declined more rapidly at higher than lower elevations."
This double-benefit -- a general decline in wind speed at many mid-latitude sites and a further decline in wind speed at higher elevations -- should act to reduce water loss via evaporation from high altitude catchments in many of the world's mountainous regions, providing more water for people who obtain it from such sources. In addition, McVicar et al. note that the "reductions in wind speed will serve to reduce rates of actual evapotranspiration partially compensating for increases in actual evapogtranspiration due to increasing air temperatures."
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