A new model for vertical adjustment of precipitable water vapor with consideration of the time-varying lapse rate

作者：Huang, Liangke^*; Liu, Wen; Mo, Zhixiang^*; Zhang, Hongxing; Li, Junyu; Chen, Fade; Liu, Lilong; Jiang, Weiping

来源：GPS SOLUTIONS, 2023, 27(4): 170.

DOI：10.1007/s10291-023-01506-5

• Precipitable water vapor (PWV)
• Vertical adjustment model
• Time-varying lapse rate
• Global Navigation Satellite Systems (GNSS)

Precipitable water vapor (PWV) is an essential parameter in numerical weather prediction and climate research. Existing global empirical PWV models rely on a single coefficient for vertical adjustment and lack geographical differentiation. Therefore, this study developed the global PWV vertical adjustment model (GPWV-H) by considering the time-varying lapse rate using the fifth-generation European Centre for Medium-Range Weather Forecasts Atmospheric Reanalysis (ERA5) from 2012 to 2017. The performance of the GPWV-H model in vertical adjustment is evaluated using multi-source PWV data and compared with the conventional empirical model (EPWV-H). The numerical results are as follows: (1) The bias and root mean square (RMS) of the GPWV-H model are - 0.10/ - 0.35 mm and 1.43/1.07 mm, respectively, when ERA5 and radiosonde PWV profiles were used as reference which are 9.3 and 5.9% (in RMS) lower than EPWV-H model; (2) The GPWV-H model improved by 15.1-17.1 and 0.8-1.6% compared to the non-adjustment and the EPWV-H model, respectively, when interpolating Second Modern-Era Retrospective Analysis for Research and Applications (MERRA-2) with various grid resolutions to radiosonde stations. These results indicate that the GPWV-H model outperforms the EPWV-H model regarding global PWV interpolation accuracy and stability and has a promising application tendency in global real-time and high-precision water vapor monitoring.

• 单位
  Wuhan University; Chinese Academy of Science; Guilin University Of Technology