甘肃科学学报

为深入了解河北省保定市上空水汽的时空分布，基于2018年12月—2021年11月保定市6个地面观测站逐时降水和地基全球定位系统(GPS)可降水量(Pwv)以及第五代欧洲再分析资料(ERA5),采用统计学方法对各代表站Pwv时间变化及其与降水的关系进行了深入分析。结果表明：GPS-Pwv月际变化存在明显的单峰型，海拔与GPS-Pwv存在反向关系。季节不同GPS-Pwv距平日变化有差异，春季，西北部山区和平原代表站GPS-Pwv平均距平日变化均为双峰结构，浅山区代表站为多峰结构；夏季，GPS-Pwv平均距平日变化都以单峰结构为主，各站出现最大变幅；秋季，浅山区和平原代表站为多峰结构，西北部山区代表站和春季类似；冬季各站GPS-Pwv平均距平日变化平缓，各站出现最小变幅。降水与GPS-Pwv存在密切关系，GPS-Pwv峰值出现时刻比降水开始时间滞后0～2 h发生的频次最高，其次是超前降水1～3 h。受不同天气系统影响，降水期间Pwv大小和降水结束之后Pwv变化趋势均不相同，降水效率与Pwv峰值高度相关。此研究不仅揭示了本地水汽的时空变化特征，而且为降水预报提供了有利的技术支撑。

In order to understand the spatial and temporal distribution of water vapor over Baoding, based on the hourly precipitation and ground-based GPS precipitable water vapor of six ground observation stations in Baoding from December 2018 to November 2021 and ERA5 reanalysis data, the time variation of Pwv and its relationship with precipitation at each representative station were analyzed by statistical method.The results show that the inter-monthly variation of GPS-Pwv is unimodal, there is an inverse relationship between altitude and GPS-Pwv.The distance variation of GPS-Pwv is different in different seasons.In spring, the average distance variation of GPS-Pwv in mountainous areas of northwest Baoding and plain areas shows a bimodal structure, while that of representative stations in shallow mountainous areas shows a multi-modal structure.In summer, the average distance variation of GPS-Pwv is mainly unimodal, and the maximum variation amplitude appears at each station.In autumn, the average distance variation of GPS-Pwv in shallow mountainous and plain area are multi-peak structure, and the average distance variation of GPS-Pwv in the northwest mountain area is similar to the spring.In winter, the distance variation of GPS-Pwv in every stations changes gently, and the minimum variation occurs at each station.There is a close relationship between precipitation and GPS-Pwv, the peak time of GPS-Pwv is the most frequent occurrence 0～2 hours after the beginning time of precipitation, followed by the advance precipitation 1～3 hours.Influenced by different weather systems, the Pwv magnitude during precipitation and the Pwv variation trend after precipitation are different, the precipitation efficiency is highly correlated with the peak value of Pwv.This study not only reveals the spatio-temporal variation characteristics of local water vapor, but also provides favorable technical support for precipitation forecast.