Abstract
The Inner Mongolia Autonomous Region is an ecological protective screen in northern China. Precipitable water vapor (PWV) products with high precision and spatiotemporal resolution are critical for climate research in this region. This study evaluates PWV using global navigation satellite system (GNSS), radiosonde, ERA5, and MERRA-2 data. Comparison of GNSS PWV and radiosonde PWV yields an average bias of -0.68 mm and root mean square error of 2.17 mm, indicating the high accuracy of GNSS PWV and its potential for assessing other products. Relative to GNSS, ERA5 and MERRA-2 exhibit annual average biases of 0.17 and 0.39 mm and annual average RMSE values of 1.63 and 2.99 mm, respectively. Diurnal anomaly variation ranges remain within -0.6 to 0.6 mm for all three datasets. The results demonstrate that ERA5 and MERRA-2 PWV are applicable in Inner Mongolia, with ERA5 showing better consistency with GNSS PWV.
