Observational evidence from two mountainous regions that near-surface wind speeds are declining more rapidly at higher elevations than lower elevations: 1960-2006

Coupling recent observed declines of terrestrial mid-latitude near-surface wind speed (u) with knowledge that high-elevation sites rapidly experience climate change led to an assessment of the regional near-surface elevation dependence of u (u(Z)) at two mountainous regions (central China and Switzerland). The monthly u(Z) were calculated from 1960-2006. In both regions u(Z) were higher in winter (similar to 2.25 m s(-1) km(-1)) compared to summer (similar to 1.25 m s(-1) km(-1)). For the first time u(Z) trends were calculated, the results were strongly seasonal, ranging from similar to-0.025 m s(-1) km(-1) a(-1) in winter to similar to-0.005 m s(-1) km(-1) a(-1) in summer. For both regions u(Z) trend results showed that u has declined more rapidly at higher than lower elevations, even though different u dynamics were observed. The u(Z) trends have important implications for climatic changes of coupled land-surface/boundary-layer processes (such as evapotranspiration) at high-elevation regions where much of the globe's fresh water is derived. Citation: McVicar, T. R., T. G. Van Niel, M. L. Roderick, L. T. Li, X. G. Mo, N. E. Zimmermann, and D. R. Schmatz (2010), Observational evidence from two mountainous regions that near-surface wind speeds are declining more rapidly at higher elevations than lower elevations: 1960-2006, Geophys. Res. Lett., 37, L06402, doi:10.1029/2009GL042255.