with the reanalysis data f rom the National Centers of Environmental Prediction/National Centers for Atmosp heric Research (NCEP/NCAR) during the same period. The reanalysis data can captu re much of the synopticscale variability in daily mean pressure, temperature a n d relative humidity. Among them, the reanalyzed pressure is more confident than temperature and relative humidity at the Col of Zhadang Glacier and Nam Co Stati on. Differences between the reanalyzed and observational daily mean pressure and relative humidity are large in winter and less in summer, while differences bet ween the reanalyzed and observational daily mean temperature are opposite. Relia bility of reanalysis data is better at the Col of Zhadang Glacier than at Nam Co Station. The reanalyzed data can be used to study the trends of climate change in the glacier and lake area in the Nam Co Basin, and more attentions should be given to influences of topography.