利用GPS数据标校水汽辐射计的方法研究

Study on the Water Vapor Radiometer Calibration with GPS Data

对流层是影响各类对地观测、地对空观测精度的主要因素之一.目前GNSS(Global Navigation Satellite System)技术由于其时空分辨率和精度方面的优越性,成为大气延迟和水汽监测的主要手段之一.水汽辐射计WVR (Water Vapor Radiometer)是传统的大气探测手段,由于其观测原理和灵敏度等方面的特点,也有其特殊的用途. WVR在正式投入使用前必须根据各个测站的具体情况进行标校,一般采用探空数据来进行,但探空数据采样频率低、数据量小, GNSS具有相对的优势.利用分布于北京(BJMY)、上海(SHAO)、昆明(YNKM)、乌鲁木齐(URUM) 4个VLBI (Very Long Baseline Interferometry)台站的GPS和水汽辐射计数据,开展了利用GPS数据标校WVR的方法研究,探讨了各个台站WVR的数据预处理方法,分析了影响水汽辐射计测量精度的因素.利用2015–2016年的4个并置台站的GPS和WVR观测数据,验证水汽辐射计数据的稳定性与可靠性.采用归一化处理方法,利用GPS数据对水汽辐射计进行了校准,为水汽辐射计的标校提供了一种新的思路和方法.

Troposphere is one of the main factors affecting the accuracy of earth observation and space exploration systems.At present,GNSS(Global Navigation Satellite System)has been regarded as one of the main methods for atmospheric delay and water vapor monitoring owing to the advantage of its accuracy and spatio-temporal resolution.Water Vapor Radiometer(WVR)is one of the traditional means for atmospheric observation with special characteristics because of its observation principle,sensitivity,and so forth.However,WVR has to be calibrated for specific circumstances of each station before being put into operation.Radiosonde data are often used for the calibration of WVR.However,GNSS has comparative advantages relative to the low sampling rate and small data size of Radiosonde.In this article,the calibration of WVR with GPS data has been studied at four GPS/WVR co-located stations in Beijing,Shanghai,Kunming,and Urumqi.Thus,the data preprocessing of each WVR is discussed in detail.The factors affecting the measurement accuracy of WVR are also analyzed.With the GPS and WVR observations of four co-located stations in 2015–2016,the stability and reliability of WVR are also verified.With the method of normalization,the WVR observations at four stations are calibrated by using the corresponding GPS data.