ITRF2014框架下顾及降雨量与水文负载的CMONOC坐标时间序列关系分析

Analysis of Relationship Between CMONOC Coordinate Time Series Considering Rainfall and Hydrological Loading Under ITRF2014 Framework

水文负载对中国大陆构造环境监测网络(crustal movement observation network of China,CMONOC)测站坐标时间序列具有重要的影响,而降雨量直接影响了水文负载的量级大小。利用ITRF2014(international terrestrial reference frame 2014)参考框架下CMONOC坐标时间序列、MERRA2(modern-era retrospective analysis for research and applications, version 2)水文负载模型以及中国区域降雨量数据来分析三者之间的关系。结果表明,水文负载对CMONOC测站的影响主要体现在垂直方向上,尤其在珠江流域、长江流域以南、西南以及东南诸河流域,水文负载对测站位移的影响尤为显著,水文负载序列的均方根最大可达5.47 mm。水文负载和降雨量都呈现出较为明显的纬度相关性,纬度越高,其量级越小,二者与纬度的线性拟合优度分别为0.63和0.55;同时,降雨量与水文负载也呈现明显的线性关系,拟合优度为0.49,且随着年均降雨量的增加,水文负载的量级会随之增大。对于周期性信号,降雨量、水文负载以及CMONOC坐标时间序列具有一致性,水文负载的周年振幅和CMONOC坐标时间序列的周年振幅与年均降雨量的拟合优度分别为0.64和0.37。在研究水文负载对GNSS坐标时间序列的影响时,除了土壤湿度、积雪以及冠层水,降雨量也是不可忽略的因素。

Objectives Hydrological loading has an important influence on crustal movement observation network of China(CMONOC)coordinate time series,and rainfall directly affects the magnitude of hydrological loading.Methods We use CMONOC coordinate time series under the international terrestrial reference frame 2014(ITRF2014),MERRA2(modern-era retrospective analysis for research and applications,version 2)model and the rainfall data in China to analyze the relationship among them.Results The results show that the impact of hydrological loading on the CMONOC stations is mainly reflected in the vertical direction.Especially in the Pearl River Basin and the south,southwest and southeast of the Yangtze River Basin,the hydrological loading has a significant influence on the displacement of the stations.The maximum root mean square value of the hydrological loading series can reach 5.47 mm.Both hydrological loading and rainfall show relatively obvious latitude correlation.The higher the latitude,the smaller of the magnitude of hydrological loading and rainfall,and the goodness of fit with R2 can reach 0.63 and 0.55,respectively.At the same time,the rainfall and hydrological loading also show an obvious linear relationship,with R2 reaching 0.49.If the average annual rainfall increases,the magnitude of hydrological loading also increases.For periodic signals,the rainfall,hydrological loading and CMONOC coordinate time series are consistent.The annual amplitude of hydrological loading and CMONOC coordinate time series with the annual average rainfall all show a relatively obvious linear relationship,and R2 reach 0.64 and 0.37,respectively.Conclusions In the study of the influence of hydrological loading on global navigation satellite system coordinate time series,in addition to soil moisture,snow cover and canopy water,rainfall is also a part of the reasons that need to be discussed.