国内外测站GNSS-IR土壤湿度反演的对比分析

Comparative analysis of soil moisture inversion by GNSS-IR at domestic and foreign stations

针对中国内地构造环境监测网络数据能否反演测站周围土壤湿度的问题,该文利用全球导航卫星系统干涉反射测量(GNSS-IR)算法以及多元线性回归模型,反演了国内外6个连续GNSS观测站周边的土壤湿度,并对反演结果进行了对比分析。结果表明:(1)美国P041和P043测站2011年年积日131—290观测数据的多元回归延迟相位与土壤湿度高度相关,其相关系数分别为0.9818和0.9845,较单颗卫星的计算结果至少提高了6.22%和3.45%;(2)相比国外测站的实验结果,国内NMDW、NMEL、NMZL和NMAY测站2019年年积日101—200观测数据的多元回归延迟相位与土壤湿度间相关性减弱,对应的相关系数分别为0.7681、0.6878、0.7601和0.8316,这种差别可能由观测站的环境引起,但较单颗卫星的结果至少分别提高了43.22%、30.64%、51.05%和29.23%;(3)反射信号分量误差对延迟相位与土壤湿度间的相关系数有较大影响,且对国内测站的影响更加显著。

Aiming at the question of whether the continuous station data of the tectonic environment monitoring network in China's Mainland can invert the soil moisture around the station,the global navigation satellite system interferometric reflectometry(GNSS-IR)algorithm and multiple linear regression model were used to invert the soil moisture around six continuous GNSS observation stations at home and abroad,the inversion results were compared and analyzed.The results showed that:(1)Based on the SNR data from DOY(day of year)131-290 in 2011 at both P041 and P043 stations in the US,the multiple regression delay phase was highly correlated with soil moisture.The correlation coefficients were 0.9818 and 0.9845,the results were higher at least 6.22%and 3.45%than those inferred from single satellites.(2)Based on SNR data from DOY 101-200 in 2019 at four domestic stations,including NMDW,NMEL,NMZL and NMAY,the correlation between the multiple regression delay phase and soil moisture decreased greatly in comparison with experimental results from foreign stations,and the corresponding correlation coefficients were 0.7681,0.6878,0.7601,and 0.8316,respectively.The difference may be related to the different observation environments of stations.However,the correlation coefficients derived from multiple satellites still improved separately at least 43.22%,30.64%,51.05%and 29.23%with comparison to those from single satellite.(3)The error of the reflected signal component had a great influence on the correlation coefficient between the delay phase and the soil moisture,and it had a greater impact on domestic stations.