Precipitable water vapour (PWV) is estimated using GPS data collected from the continuous operating reference station (CORS) located in Dehradun city, a valley in northwestern Himalayan region. PWV is also estimated using two well-established IGS stations observations in India to validate the retrieval process and to investigate PWV variation over these locations. Meteorological observations, required for PWV estimation, are acquired from NCEP by vertical and horizontal interpolation of grid points data for a specific station. The validation and accuracy assessment of all obtained parameters are carried out at different levels. The annual average PWV over Hyderabad (HYDE), Bangalore (IISC), and Dehradun (DEHR) are estimated to be 35.96, 31.70 and 22.10 mm, respectively. The average PWV differences are estimated to be around 1–3 mm if the comparison is made among GMET, IGS and NCEP derived PWVs. Estimated PWV over Dehradun is also compared with reanalysis data from the MERRA and an average difference of about 4 mm is observed.

可降水量水汽 (PWV) 是使用从位于喜马拉雅西北部山谷德拉敦市的连续运行参考站 (CORS) 收集的 GPS 数据估算的。还使用印度两个完善的 IGS 站观测来估计 PWV，以验证检索过程并调查这些位置的 PWV 变化。PWV 估计所需的气象观测是通过特定站点的网格点数据的垂直和水平插值从 NCEP 获得的。所有获得的参数的验证和准确性评估在不同级别进行。海得拉巴 (HYDE)、班加罗尔 (IISC) 和德拉敦 (DEHR) 的年平均 PWV 估计分别为 35.96、31.70 和 22.10 毫米。如果在 GMET、IGS 和 NCEP 派生的 PWV 之间进行比较，平均 PWV 差异估计约为 1-3 毫米。德拉敦的估计 PWV 也与来自 MERRA 的再分析数据进行了比较，观察到平均差异约为 4 毫米。