Nonlinear Processes in Geophysics最新文献_第8页

Control simulation experiments of extreme events with the Lorenz-96 model Lorenz-96模型对极端事件的控制模拟实验

IF 2.2 4区地球科学

Nonlinear Processes in Geophysics Pub Date : 2023-06-19 DOI: 10.5194/npg-30-117-2023

Q. Sun, T. Miyoshi, S. Richard

引用次数: 1

Exploring meteorological droughts' spatial patterns across Europe through complex network theory 通过复杂网络理论探索欧洲各地的气象干旱空间模式

IF 2.2 4区地球科学

Nonlinear Processes in Geophysics Pub Date : 2023-06-15 DOI: 10.5194/npg-30-167-2023

Domenico Giaquinto, W. Marzocchi, Jürgen Kurths

引用次数: 0

Toward a multivariate formulation of the parametric Kalman filter assimilation: application to a simplified chemical transport model 参数卡尔曼滤波同化的多元公式：在简化化学迁移模型中的应用

IF 2.2 4区地球科学

Nonlinear Processes in Geophysics Pub Date : 2023-06-14 DOI: 10.5194/npg-30-139-2023

Antoine Perrot, O. Pannekoucke, V. Guidard

{"title":"Toward a multivariate formulation of the parametric Kalman filter assimilation: application to a simplified chemical transport model","authors":"Antoine Perrot, O. Pannekoucke, V. Guidard","doi":"10.5194/npg-30-139-2023","DOIUrl":"https://doi.org/10.5194/npg-30-139-2023","url":null,"abstract":"Abstract. This contribution explores a new approach to forecasting multivariate covariances for atmospheric chemistry through the use of the parametric Kalman filter (PKF). In the PKF formalism, the error covariance matrix is modellized by a covariance model relying on parameters, for which the dynamics are then computed. The PKF has been previously formulated in univariate cases, and a multivariate extension for chemical transport models is explored here. This contribution focuses on the situation where the uncertainty is due to the chemistry but not due to the uncertainty of the weather. To do so, a simplified two-species chemical transport model over a 1D domain is introduced, based on the non-linear Lotka–Volterra equations, which allows us to propose a multivariate pseudo covariance model. Then, the multivariate PKF dynamics are formulated and their results are compared with a large ensemble Kalman filter (EnKF) in several numerical experiments. In these experiments, the PKF accurately reproduces the EnKF. Eventually, the PKF is formulated for a more complex chemical model composed of six chemical species (generic reaction set). Again, the PKF succeeds at reproducing the multivariate covariances diagnosed on the large ensemble.","PeriodicalId":54714,"journal":{"name":"Nonlinear Processes in Geophysics","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43763184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Data-driven reconstruction of partially observed dynamical systems 部分观测动力系统的数据驱动重构

IF 2.2 4区地球科学

Nonlinear Processes in Geophysics Pub Date : 2023-06-09 DOI: 10.5194/npg-30-129-2023

P. Tandeo, P. Ailliot, F. Sévellec

{"title":"Data-driven reconstruction of partially observed dynamical systems","authors":"P. Tandeo, P. Ailliot, F. Sévellec","doi":"10.5194/npg-30-129-2023","DOIUrl":"https://doi.org/10.5194/npg-30-129-2023","url":null,"abstract":"Abstract. The state of the atmosphere, or of the ocean, cannot be exhaustively observed. Crucial parts might remain out of reach of proper monitoring. Also, defining the exact set of equations driving the atmosphere and ocean is virtually impossible because of their complexity. The goal of this paper is to obtain predictions of a partially observed dynamical system without knowing the model equations. In this data-driven context, the article focuses on the Lorenz-63 system, where only the second and third components are observed and access to the equations is not allowed. To account for those strong constraints, a combination of machine learning and data assimilation techniques is proposed. The key aspects are the following: the introduction of latent variables, a linear approximation of the dynamics and a database that is updated iteratively, maximizing the likelihood. We find that the latent variables inferred by the procedure are related to the successive derivatives of the observed components of the dynamical system. The method is also able to reconstruct accurately the local dynamics of the partially observed system. Overall, the proposed methodology is simple, is easy to code and gives promising results, even in the case of small numbers of observations.\u0000","PeriodicalId":54714,"journal":{"name":"Nonlinear Processes in Geophysics","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42882181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

On parameter bias in earthquake sequence models using data assimilation 利用资料同化的地震序列模型中的参数偏差

IF 2.2 4区地球科学

Nonlinear Processes in Geophysics Pub Date : 2023-04-05 DOI: 10.5194/npg-30-101-2023

A. Banerjee, Ylona van Dinther, F. Vossepoel

{"title":"On parameter bias in earthquake sequence models using data assimilation","authors":"A. Banerjee, Ylona van Dinther, F. Vossepoel","doi":"10.5194/npg-30-101-2023","DOIUrl":"https://doi.org/10.5194/npg-30-101-2023","url":null,"abstract":"Abstract. The feasibility of physics-based forecasting of earthquakes depends on how well models can be calibrated to represent earthquake scenarios given\u0000uncertainties in both models and data. We investigate whether data assimilation can estimate current and future fault states, i.e., slip rate and\u0000shear stress, in the presence of a bias in the friction parameter. We perform state estimation as well as combined state-parameter estimation using\u0000a sequential-importance resampling particle filter in a zero-dimensional (0D) generalization of the Burridge–Knopoff spring–block model with rate-and-state\u0000friction. Minor changes in the friction parameter ϵ can lead to different state trajectories and earthquake characteristics. The\u0000performance of data assimilation with respect to estimating the fault state in the presence of a parameter bias in ϵ depends on the magnitude of the\u0000bias. A small parameter bias in ϵ (+3 %) can be compensated for very well using state estimation (R2 = 0.99), whereas an\u0000intermediate bias (−14 %) can only be partly compensated for using state estimation (R2 = 0.47). When increasing particle spread by accounting for model error and\u0000an additional resampling step, R2 increases to 0.61. However, when there is a large bias (−43 %) in ϵ, only state-parameter\u0000estimation can fully account for the parameter bias (R2 = 0.97). Thus, simultaneous state and parameter estimation effectively separates the\u0000error contributions from friction and shear stress to correctly estimate the current and future shear stress and slip rate. This illustrates the\u0000potential of data assimilation for the estimation of earthquake sequences and provides insight into its application in other nonlinear processes with\u0000uncertain parameters.\u0000","PeriodicalId":54714,"journal":{"name":"Nonlinear Processes in Geophysics","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43067992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Physically Constrained Covariance Inflation from Location Uncertainty 位置不确定性的物理约束协方差膨胀

IF 2.2 4区地球科学

Nonlinear Processes in Geophysics Pub Date : 2023-03-09 DOI: 10.13140/rg.2.2.18433.53603

Yicun Zhen, Valentin Resseguier, Bertrand Chapron

引用次数: 0

A range of outcomes: the combined effects of internal variability and anthropogenic forcing on regional climate trends over Europe 一系列结果：内部变化和人为作用力对欧洲区域气候趋势的综合影响

IF 2.2 4区地球科学

Nonlinear Processes in Geophysics Pub Date : 2023-02-15 DOI: 10.5194/npg-30-63-2023

C. Deser, A. Phillips

引用次数: 7

Extending ensemble Kalman filter algorithms to assimilate observations with an unknown time offset 扩展集合卡尔曼滤波算法以同化具有未知时间偏移的观测

IF 2.2 4区地球科学

Nonlinear Processes in Geophysics Pub Date : 2023-02-07 DOI: 10.5194/npg-30-37-2023

Elia Gorokhovsky, Jeffrey L. Anderson

{"title":"Extending ensemble Kalman filter algorithms to assimilate observations with an unknown time offset","authors":"Elia Gorokhovsky, Jeffrey L. Anderson","doi":"10.5194/npg-30-37-2023","DOIUrl":"https://doi.org/10.5194/npg-30-37-2023","url":null,"abstract":"Abstract. Data assimilation (DA), the statistical combination of\u0000computer models with measurements, is applied in a variety of scientific\u0000fields involving forecasting of dynamical systems, most prominently in\u0000atmospheric and ocean sciences. The existence of misreported or unknown\u0000observation times (time error) poses a unique and interesting problem for\u0000DA. Mapping observations to incorrect times causes bias in the prior state\u0000and affects assimilation. Algorithms that can improve the performance of\u0000ensemble Kalman filter DA in the presence of observing time error are\u0000described. Algorithms that can estimate the distribution of time error are\u0000also developed. These algorithms are then combined to produce extensions to\u0000ensemble Kalman filters that can both estimate and correct for observation\u0000time errors. A low-order dynamical system is used to evaluate the\u0000performance of these methods for a range of magnitudes of observation time\u0000error. The most successful algorithms must explicitly account for the\u0000nonlinearity in the evolution of the prediction model.\u0000","PeriodicalId":54714,"journal":{"name":"Nonlinear Processes in Geophysics","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44682966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the interaction of stochastic forcing and regime dynamics 随机强迫与状态动力学的相互作用

IF 2.2 4区地球科学

Nonlinear Processes in Geophysics Pub Date : 2023-02-07 DOI: 10.5194/npg-30-49-2023

J. Dorrington, T. Palmer

引用次数: 4

Brief communication: Climate science as a social process – history, climatic determinism, Mertonian norms and post-normality 简要交流:气候科学作为一个社会过程-历史，气候决定论，默顿规范和后常态

IF 2.2 4区地球科学

Nonlinear Processes in Geophysics Pub Date : 2023-01-31 DOI: 10.5194/npg-30-31-2023

H. von Storch

{"title":"Brief communication: Climate science as a social process – history, climatic determinism, Mertonian norms and post-normality","authors":"H. von Storch","doi":"10.5194/npg-30-31-2023","DOIUrl":"https://doi.org/10.5194/npg-30-31-2023","url":null,"abstract":"Abstract. For ages, the topic of climate – in the sense of “usual weather” – has in the western tradition attracted attention as a possible explanatory factor for differences in societies and in human behavior. Climate, and its purported impact on society, is an integrated element in western thinking and perception. In this essay, the history of ideas about the climatic impact on humans and society and the emergence of the ideology of climatic determinism are sketched from the viewpoint of a natural scientist. This ideology favored the perception of westerners being superior to the people in the rest of the world, giving legitimacy to colonialism. In modern times, when natural sciences instituted self-critical processes (repeatability, falsification) and norms (such as the Mertonian norms named CUDOS), the traditional host for climate issues, namely, geography, lost its grip, and physics took over. This “scientification” of climate science led to a more systematic, critical and rigorous approach of building and testing hypotheses and concepts. This gain in methodical rigor, however, went along with the loss of understanding that climate is hardly a key explanatory factor for societal differences and developments. Consequently, large segments of the field tacitly and unknowingly began reviving the abandoned concept of climatic determinism. Climate science finds itself in a “post-normal” condition, which leads to a frequent dominance of political utility over methodical rigor.\u0000","PeriodicalId":54714,"journal":{"name":"Nonlinear Processes in Geophysics","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43535325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1