In this study, precipitable water is estimated from GPS data with high time resolution at Lhasa. Mean precipitable water in the premonsoon and the monsoon periods are about 10mm and 25mm, respectively, while precipitable water increases in short term at around the onset. Prominent diurnal variation of precipitable water can be observed in both periods. The minima of the diurnal variation appear around 1800 LST and 1500 LST in the premonsoon and the monsoon periods, respectively. These characteristics indicate that the diurnal variation of water vapor is strongly affected by the local circulation over the deep valley.
In case of analyzing the wind turbine design conditions and power productions accurately, the wind data at hub height is generally ideated for simulation. Recently, due to the increase in the size of the wind turbine, it is difficult to measure wind data of hub height by the cylindrical observation tower. Therefore, lattice tower mast is adopted and there are cases where high altitude measurement is performed instead of cylindrical tower mast. However, even in case of measuring wind data using lattice tower mast, there are some uncertainty of flow distortions by tower shadowing. This paper shows a study on wind speed correction method of lattice tower mast using CFD simulations (Fluent). As a result of performing the wind speed correction using the inflow wind speed ratio by CFD calculation, the uncertainty of corrected wind speed fell by less than 1 % which is recommended by IEC 61400-12-1.
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