Investigation on the Time-evolution of Local Boundary Layer (LBL)is carried out over a mountain ridge at Nainital (79.5oE, 29.4oN, 1958 m amsl) in the central Himalayan region, using a Radar Wind Profiler (RWP) during November 2011 to March 2012, as a part of the Ganges Valley Aerosol Experiment (GVAX). The study is restricted to clear-sunny days, resulting in a total of 78 days of observations. The standard criterion of the peak in the signal-to-noise ratio (SNR) profile was found to be inadequate in the characterization of Mixed Layer (ML) top at this site. Therefore, we implemented a new criterion of SNR > = 6 dB for the characterization of the ML and the resulting estimations are shown to be in agreement with radiosonde measurements over this site. The daytime average (0500-1000 UTC) observed boundary layer height ranges from 440±197 m in November (late autumn) to 766±317 m above ground level (AGL) in March (early spring). The observations revealed a pronounced impact of mountain-topography on the LBL dynamics during March, when strong winds (> 5.6 m s-1) lead to LBL heights of 650 m during nighttime.These results are also utilized to evaluate WRM model for boundary layer.Sensitivity simulations using a Mixed Layer model (MXL/MESSy) were also carried out which indicated that the springtime overestimation of LBL would lead to a minor uncertainty in simulated surface ozone concentrations.