The GRACE(Gravity Recovery and Climate Experiment)space mission recorded temporal variation characteristics of the global gravity field at decadal timescales.The gravity data have been shown to capture the dynamics of...The GRACE(Gravity Recovery and Climate Experiment)space mission recorded temporal variation characteristics of the global gravity field at decadal timescales.The gravity data have been shown to capture the dynamics of flows within the outer core and their effects on the core-mantle boundary.We first aim to remove global surface process gravity signals from the GRACE data.We then construct the global core magnetic field according to the CHAOS-7 model.Finally,we apply the blind source separation method to decompose the processed gravity signals and core magnetic signals and compute the power spectral density of the gravity and magnetic field signals by using the Lomb-Scargle periodogram approach.We have discovered a signal cycle(of~6 years)in the principal components of the core magnetic and gravity signals,potentially as a result of deep Earth processes.The main principal components of the core magnetic and gravity signals reveal that the variation trends in the second-order time derivative of the core magnetic field are similar to those in the gravity field.After 2014,the second-order time derivative of the core magnetic field exhibited linear and rapid change characteristics,which were the same as the change in the gravity field and are consistent with existing research results.展开更多
为了解决传统硬阈值方法在处理异常测站时难以应对模糊边界的问题,提出一种新方法,将构造运动和观测误差引起的测站异常均视为粗差,并利用隶属度函数构建IGGⅢ等价权函数,以减小异常测站的影响。新方法引入模糊集理论,是一种基于标准化...为了解决传统硬阈值方法在处理异常测站时难以应对模糊边界的问题,提出一种新方法,将构造运动和观测误差引起的测站异常均视为粗差,并利用隶属度函数构建IGGⅢ等价权函数,以减小异常测站的影响。新方法引入模糊集理论,是一种基于标准化残差属于粗差的模糊子集隶属度函数改进的IGGⅢ抗差估计方法(membership function IGGⅢ,MF-IGGⅢ)。首先,通过模糊统计确定标准化残差受粗差污染程度最大的模糊子集的隶属度函数;然后,依据这些隶属度函数值构建等价权函数,并进行选权迭代。模拟实验和对环渤海区域GNSS速度场的拟合分析结果表明,该方法在异常测站检测方面的表现优于假设检验法、均值漂移法和IGGⅢ法,显示出较强的异常测站识别能力。展开更多
基金the National Natural Science Foundation of China(Grant Nos.42274003,41974007,and 41774019).
文摘The GRACE(Gravity Recovery and Climate Experiment)space mission recorded temporal variation characteristics of the global gravity field at decadal timescales.The gravity data have been shown to capture the dynamics of flows within the outer core and their effects on the core-mantle boundary.We first aim to remove global surface process gravity signals from the GRACE data.We then construct the global core magnetic field according to the CHAOS-7 model.Finally,we apply the blind source separation method to decompose the processed gravity signals and core magnetic signals and compute the power spectral density of the gravity and magnetic field signals by using the Lomb-Scargle periodogram approach.We have discovered a signal cycle(of~6 years)in the principal components of the core magnetic and gravity signals,potentially as a result of deep Earth processes.The main principal components of the core magnetic and gravity signals reveal that the variation trends in the second-order time derivative of the core magnetic field are similar to those in the gravity field.After 2014,the second-order time derivative of the core magnetic field exhibited linear and rapid change characteristics,which were the same as the change in the gravity field and are consistent with existing research results.
文摘为了解决传统硬阈值方法在处理异常测站时难以应对模糊边界的问题,提出一种新方法,将构造运动和观测误差引起的测站异常均视为粗差,并利用隶属度函数构建IGGⅢ等价权函数,以减小异常测站的影响。新方法引入模糊集理论,是一种基于标准化残差属于粗差的模糊子集隶属度函数改进的IGGⅢ抗差估计方法(membership function IGGⅢ,MF-IGGⅢ)。首先,通过模糊统计确定标准化残差受粗差污染程度最大的模糊子集的隶属度函数;然后,依据这些隶属度函数值构建等价权函数,并进行选权迭代。模拟实验和对环渤海区域GNSS速度场的拟合分析结果表明,该方法在异常测站检测方面的表现优于假设检验法、均值漂移法和IGGⅢ法,显示出较强的异常测站识别能力。
