Analysis Of Coordinate Time Series Of CORS Station In Bohai Region Based On Environmental Load

With the continuous increase of the CORS station in Bohai Rim area,a large amount of GNSS observation data have been accumulated in the area around Bohai Rim area,which provides a valuable reliable data basis for the study of the characteristics of the crustal deformation in this region.The coordinate time series of the CORS station can reflect the trend change of the station,but there are some systematic errors in the coordinate tine series,especially caused by environmental load(such as atmospheric load,non-tidal ocean load,snow and soil moisture load,etc.)The nonlinear change of the station cannot be ignored.The effect on the displacement of the station is often in the same order of magnitude as the deformation of the station.In addition,common-mode errors,colored noise,and other errors exist in the time series in the regional CORS network.Therefore,the effective separation and elimination of the effects of various errors from the CORS station coordinate time series and the accurate estimation of the station noise model are of great significance for us to study the regional structural deformation and dynamic mechanism more precisely.This article mainly focuses on the 2011-2015 data of 42 CORS stations in Bohai Ril area for a total of 5 years.The coordinate time series calculated by GAMIT/GLOBK software is taken as the research object.Based on the previous research work,the influence of environmental load on the coordinate time series of the CORS station is studied and analyzed.The specific research contents are as follows:(1)The principle and method of quantitative calculation of the effect of environmental load on station displacement are introduced in detail.The currently used earth model is described and the detailed process of calculating the displacement of the station caused by the environmental load based on Farrell surface load Green's function is deduced.(2)The GAMIT/GLOBK software was used to solve the observation data of 42 CORS stations in Bohai Rim area and 11 IGS stations in the Chinese mainland and surrounding areas for the past 5 years.The coordinate time series of each survey station are obtained,and the time series of the acquired station coordinates are preprocessed.(3)Combined with the survey area overview,the correlation coefficient-weighted stacking method was used to extract the common-mode errors and the station time series was corrected.The correcting effect was compared with the traditional stacking method.(4)Combined with the survey area,the correlation coefficient weighted stack method is used to extract the common mode error and to correct the time series of the station,and the correction effect is compared with the traditional stack method.(5)Based on the spectral index analysis and maximum likelihood method,the optimal noise of the station coordinate time series is estimated,and the influence of the environmental load on the optimal noise model is studied and analyzed.The influence of the colored noise on the regional velocity field is studied and analyzed according to the optimal noise model of each station.