Full Column Research Articles

Exploring multi-decadal time series of temperature extremes in Australian coastal waters

Abstract. The intensity and frequency of extreme ocean temperature events, such as marine heatwaves (MHWs) and marine cold spells (MCSs), are expected to change as our oceans warm. Little is known about marine extremes in Australian coastal waters, particularly below the surface. Here we introduce a multi-decadal observational record of extreme ocean temperature events starting in the 1940s and 1950s between the surface and the bottom (50–100 m) at four long-term coastal sites around Australia: the Australian Multi-Decadal Ocean Time Series EXTreme (AMDOT-EXT) data products (https://doi.org/10.26198/wbc7-8h24, Hemming et al., 2024). The data products include indices indicating the timing of extreme warm and cold temperature events, their intensity and the corresponding temperature time series and climatology thresholds. We include MHWs, MCSs and shorter-duration heat spikes and cold spikes. For MHWs and MCSs, which are defined as anomalies above the daily varying 90th and 10th percentiles, respectively, and lasting more than 5 d, we also provide further event information, such as their category and onset and decline rates. The four data products are provided as CF-compliant NetCDF files, and it is our intention that they be updated periodically. It is advised that data users seek the latest data product version. Using these multi-decadal data products, we show the most intense and longest extreme temperature events at these sites, which have occurred below the surface. These data records highlight the value of long-term full water column ocean data for the identification of extreme temperature events below the surface.

Phase‐Accurate Internal Tides in a Global Ocean Forecast Model: Potential Applications for Nadir and Wide‐Swath Altimetry

AbstractInternal tides (ITs) play a critical role in ocean mixing, and have strong signatures in ocean observations. Here, global IT sea surface height (SSH) in nadir altimetry is compared with an ocean forecast model that assimilates de‐tided SSH from nadir altimetry. The forecast model removes IT SSH variance from nadir altimetry at skill levels comparable to those achieved with empirical analysis of nadir altimetry. Accurate removal of IT SSH is needed to fully reveal lower‐frequency mesoscale eddies and currents in altimeter data. Analysis windows of order 30–120 days, made possible by the frequent (hourly) outputs of the forecast model, remove more IT SSH variance than longer windows. Forecast models offer a promising new approach for global internal tide mapping and altimetry correction. Because they provide information on the full water column, forecast models can also help to improve understanding of the underlying dynamics of ITs.

Componentwise Perturbation Analysis of the Singular Value Decomposition of a Matrix

A rigorous perturbation analysis is presented for the singular value decomposition (SVD) of a real matrix with full column rank. It is proved that the SVD perturbation problem is well posed only when the singular values are distinct. The analysis involves the solution of symmetric coupled systems of linear equations. It produces asymptotic (local) componentwise perturbation bounds on the entries of the orthogonal matrices participating in the decomposition of the given matrix and on its singular values. Local bounds are derived for the sensitivity of the singular subspaces measured by the angles between the unperturbed and perturbed subspaces. Determining the asymptotic bounds of the orthogonal matrices and the sensitivity of singular subspaces requires knowing only the norm of the perturbation of the given matrix. An iterative scheme is described to find global bounds on the respective perturbations, and results from numerical experiments are presented.

Invertible bases and root vectors for analytic matrix-valued functions

We revisit the concept of a minimal basis through the lens of the theory of modules over a commutative ring $R$. We first review the conditions for the existence of a basis for submodules of $R^n$ where $R$ is a Bézout domain. Then, we define the concept of invertible basis of a submodule of $R^n,$ and when $R$ is an elementary divisor domain, we link it to the Main Theorem of G. D. Forney Jr. [SIAM J. Control, 13:493-520, 1975]. Over an elementary divisor domain, the submodules admitting an invertible basis are precisely the free pure submodules of $R^n$. As an application, we let $\Omega \subseteq \mathbb{C}$ be either a connected compact set or a connected open set, and we specialize to $R=\mathcal{A}(\Omega)$, the ring of functions that are analytic on $\Omega$. We show that, for any matrix $A(z) \in \mathcal{A}(\Omega)^{m \times n}$, $\ker A(z) \cap \mathcal{A}(\Omega)^n$ is a free $\mathcal{A}(\Omega)$-module and admits an invertible basis, or equivalently a basis that is full rank upon evaluation at any $\lambda \in \Omega$. Finally, given $\lambda \in \Omega$, we use invertible bases to define and study maximal sets of root vectors at $\lambda$ for $A(z)$. This in particular allows us to define eigenvectors also for analytic matrices that do not have full column rank.

Kalman Filter for Linear Discrete-Time Rectangular Singular Systems Considering Causality

This paper proposes a Kalman filter for linear rectangular singular discrete-time systems, where the singular matrix in the system is a rectangular matrix without full column rank. By using two different restricted equivalent transformation methods and adding the measurement equation to the state equation, the system is transformed into a square singular system satisfying regularity and observability. During this process, the causality of the system is taken into account, and multiple matrix transformations are applied accordingly. Based on these modifications, state estimation results are obtained using the Kalman filter. Finally, a numerical example is employed to demonstrate the effectiveness of our approach.

Hydrodynamics and Sediment Transport at Socheongcho Ocean Research Station, Korea, in the Yellow Sea

A seasonal variability in flow and sediment flux at the Socheongcho Ocean Research Station (SORS) on the west coast of Korea in 2018 was investigated to elucidate the formation of a two-layered flow structure and changes in sediment transport during stratification. An analysis of SORS data revealed stable temperatures (5–10 °C) in deeper waters, while surface temperatures rose from 6 °C in April to a peak of 30 °C in late August, gradually declining and leading to full water column mixing by late November. This temperature variation induced stratification, influencing the development of a two-layered flow structure. In winter, a singular flow structure was observed, contrasting with the emergence of a two-layered structure as stratification progressed. In the surface layer, residual currents flowed northward in summer and southward in winter, consistent with previous studies. In deeper layers, a southward residual current persisted, irrespective of the season. Sediment flux consistently moved southward, regardless of the season or water depth, with notably higher cumulative sediment flux in the deeper layer (1300 kg·m−2s−1) compared to the surface layer (300 kg·m−2s−1). These findings diverge notably from previous studies, providing new insights into ocean currents and material transport in the Yellow Sea.

Monitoring casing corrosion of legacy wells using CSEM: Implications for large-scale energy and CO2 storage projects in shut-down hydrocarbon fields

Large-scale CO2 and energy storage is a mandatory part of the green shift to reduce CO2 emissions and limit consequences of climate change. Large-scale storage will require the use of shut-down depleted hydrocarbon fields to take advantage of well-characterized reservoirs and cap rocks. Thanks to extensive data from historical hydrocarbon production, the uncertainties related to storage capacity, injectivity, and containment are limited. However, legacy exploration and production infrastructure, and especially legacy wells, are the main threat for possible fluid leakage toward the surface. Such legacy wells are numerous and penetrate the full rock column. In this paper, we describe a workflow to screen and monitor legacy wells in the shut-down Frigg Field in the North Sea. By using numerical modeling of electromagnetic (EM) field propagation in one of the Frigg Field wells, we explore the complex interactions of fields, currents, and well structure in the presence of corrosion. The corrosion is implemented as a change in the electrical conductivity of the innermost steel casing at different depths along the structure. To enhance probing depth, we plug the dipole source (1 km long) into the casing at the seafloor and excite the casing as an antenna. We find that at moderate levels of corrosion, the current distribution is significantly modified with respect to the uncorroded case. This generates a signal that propagates and can be observed at the seafloor in the numerical results. Other elements of the well geometry (e.g., concentric overlapping cement casings) have their own effect on the signal. This leads the possibility of estimating the location of the corroded area within the well geometry. These results suggest that by relaxing some of the model's approximations and implementing realistic transmitters, it will be possible to evaluate and optimize controlled-source EM survey strategies for detecting and monitoring corrosion levels.

On the Vertical Structure of Deep-Ocean Subinertial Variability

Abstract The vertical structure of subinertial variability is examined using full-depth horizontal velocity and vertical isopycnal displacement observations derived from the Ocean Observatory Initiative (OOI). Vertical profiles on time scales between 100 h and 1 yr or longer are characterized through empirical orthogonal function decomposition and qualitatively compared with theoretical modal predictions for the cases of flat, sloping, and rough bathymetry. OOI observations were obtained from mooring clusters at four deep-ocean sites: Argentine Basin, Southern Ocean, Station Papa, and Irminger Sea. Because no single OOI mooring in these arrays provides temperature, salinity, and horizontal velocity information over the full water column, sensor observations from two or more moorings are combined. Depths greater than ∼150–300 m were sampled by McLane moored profilers; in three of the four cases, two profilers were utilized on the moorings. Because of instrument failures on the deployments examined here, only ∼2 yr of full-ocean-depth observations are available from three of the four sites and some 3+ yr from the other. Results from the OOI “global” sites are contrasted with a parallel analysis of 3.5 yr of observations about the axis of the Gulf Stream where much of the subinertial variability is associated with stream meandering past the moorings. Looking across the observations, no universal vertical structure is found that characterizes the subinertial variability at the five sites examined; regional bathymetry, stratification, baroclinicity, nonlinearity, and the forcing (both local and remote) likely all play a role in shaping the vertical structure of the subinertial variability in individual ocean regions.

OGBN P06 Co-location of pulmonary abnormalities on high resolution CT imaging and pulmonary microaspiration reflux scan: Suggests a causative relationship

Abstract Background The relationship between micro-aspiration of refluxate as a form of gastro-oesophageal reflux disease (GORD) and pulmonary diseases including bronchiectasis and lung fibrosis has been circumstantially suggested but not proven. Clarification of the role of GORD and microaspiration in pulmonary disease may enable targeted therapies. This study aims to determine whether there is a relationship between anatomical location of aspiration of radiological tracer on scintigraphic imaging and changes associated with pulmonary disease on high resolution computed tomographic imaging of the lung (HRCT-L). Methods Data were obtained from a prospectively populated database of patients with treatment resistant typical and atypical GORD and suspected reflux pulmonary microaspiration. Patients who underwent microaspiration studies and had concurrent HRCT-L for chest symptoms were included. Modified novel digital technique of reflux pulmonary microaspiration scintigraphy using a previously validated technique was performed to evaluate the possibility of significant GORD or extra-oesophageal symptoms, including typical symptoms such as heartburn and reflux and atypical symptoms such as throat symptoms, cough, globus, mucous, throat clearing, dysphonia and recurrent respiratory infections. HRCT-L was obtained in clinically indicated patients and compared with scintigraphic findings. Results Pulmonary reflux microaspiration scanning was performed in 121 patients (75% female, 25% male). The mean age was 67 years (range: 31 – 91 years). All patients demonstrated reflux microaspiration on scintigraphy in the supine delayed phase and all had intermittent or continuous full column gastro-oesophageal reflux. Lung parenchymal changes were apparent in 66 of 73 patients who underwent HRCT-L. Fibrotic changes were demonstrated in 51% of patients and bronchiectactic changes in 46%. Correlation at anatomical lobar levels with areas of aspiration of isotope on scintigraphic imaging was seen in 97% of fibrosis patients and 85% of bronchiectasis patients. Conclusions Modified reflux pulmonary microaspiration scintigraphy demonstrated the presence of pulmonary aspiration on delayed imaging. This is the first imaging technique with the ability to confirm the presence of lung aspiration of gastric content. Given the large proportion of cases showing lobar co-location of pulmonary abnormality on HRCT-L, this study indicates a strong relationship between aspiration of refluxate and parenchymal lung changes associated with pulmonary diseases such as IPF and bronchiectasis. There may be a significant role for modified technique scintigraphy to accurately diagnose the presence of reflux aspiration, allowing further research into pathogenesis and management of pulmonary disease.

Variable selection with the knockoffs: Composite null hypotheses

The fixed-X knockoff filter is a flexible framework for variable selection with false discovery rate (FDR) control in linear models with arbitrary design matrices (of full column rank) and it allows for finite-sample selective inference via the Lasso estimates. In this paper, we extend the theory of the knockoff procedure to tests with composite null hypotheses, which are usually more relevant to real-world problems. The main technical challenge lies in handling composite nulls in tandem with dependent features from arbitrary designs. We develop two methods for composite inference with the knockoffs, namely, shifted ordinary least-squares (S-OLS) and feature-response product perturbation (FRPP), building on new structural properties of test statistics under composite nulls. We also propose two heuristic variants of S-OLS method that outperform the celebrated Benjamini–Hochberg (BH) procedure for composite nulls, which serves as a heuristic baseline under dependent test statistics. Finally, we analyze the loss in FDR when the original knockoff procedure is naively applied on composite tests.

Developing a New Oxygen Atlas of the World’s Oceans Using Data Interpolating Variational Analysis

Abstract We present a new global oxygen atlas. This atlas uses all of the available full water column profiles of oxygen, salinity, and temperature available as part of the World Ocean Database released in 2018. Instead of optimal interpolation, we use the Data Interpolating Variational Analysis (DIVA) approach to map the available profiles onto 108 depth levels between the surface and 6800 m, covering more than 99% of ocean volume. This 1/2° × 1/2° atlas covers the period 1955–2018 in 1-yr intervals. The DIVA method has significant benefits over traditional optimal interpolation. It allows the explicit inclusion of advection and boundary constraints, thus offering improvements in the representations of oxygen, salinity, and temperature in regions of strong flow and near coastal boundaries. We demonstrate these benefits of this mapping approach with some examples from this atlas. We can explore the regional and temporal variations of oxygen in the global oceans. Preliminary analyses confirm earlier analyses that the oxygen minimum zone in the eastern Pacific Ocean has expanded and intensified. Oxygen inventory changes between 1970 and 2010 are assessed and compared against prior studies. We find that the full ocean oxygen inventory decreased by 0.84% ± 0.42%. For this period, temperature-driven solubility changes explain about 21% of the oxygen decline over the full water column; in the upper 100 m, solubility changes can explain all of the oxygen decrease; for the 100–600 m depth range, it can explain only 29%, 19% between 600 and 1000 m, and just 11% in the deep ocean. Significance Statement The purpose of this study is to create a new oxygen atlas of the world’s oceans using a technique that better represents the effects of ocean currents and topographic boundaries, and to investigate how oxygen in the ocean has changed over recent decades. We find the total quantity of oxygen in the world’s oceans has decreased by 0.84% since 1970, similar to previous studies. We also examine how much of this change can be explained by changes in water temperature; we find that this can explain all the changes in the upper 100 m but only 21% of the oxygen decline over the whole water column.

Evaluating the Performance of a Dual-Frequency Multibeam Echosounder for Small Target Detection

With rising interest in marine renewable energy (MRE) associated with offshore wind, waves, and tidal flows, the effects of device placement on changes in animal behaviour require proper assessment to minimise environmental impacts and inform decision making. High-frequency multibeam echosounders, or imaging sonars, can be used to observe and record the underwater movement and behaviour of animals at a fine scale (tens of metres). However, robust target detection and tracking of closely spaced animals are required for assessing animal–device and predator–prey interactions. Dual-frequency multibeam echosounders combine longer detection ranges (low frequency) with greater detail (high frequency) while maintaining a wide field of view and a full water column range compared to acoustic or optical cameras. This study evaluates the performance of the Tritech Gemini 1200ik imaging sonar at 720 kHz (low frequency) and 1200 kHz (high frequency) for small target detection with increasing range and the ability of the two frequency modes to discriminate between two closely spaced targets using a 38.1 mm tungsten carbide acoustic calibration sphere under controlled conditions. The quality of target detection decreases for both modes with increasing range, with a 25 m limit of detection at high frequency and a low-frequency mode able to detect the target up to 30 m under test conditions in shallow water. We quantified the enhanced performance of the high-frequency mode in discriminating targets at short ranges and improved target detection and discrimination at high ranges in the low-frequency mode.

On the construction and parameterization of interpolants in the Loewner framework

We develop a general method for the construction of interpolants in the Loewner framework for nonlinear differential–algebraic systems. The approach involves building a family of systems preserving the properties of Loewner equivalence and matching of tangential data functions. It is shown that under mild conditions this family of systems parameterizes all interpolants of sufficiently large dimension matching the tangential data while possessing tangential generalized controllability and observability functions with full column and row rank Jacobians. As a result, this family of systems provides all possible degrees of freedom that an interpolant can have. The results are also discussed in the linear setting and, when taken in combination with existing results, provide a broader framework for the construction of linear interpolating systems.

Phase retrieval via Lagrange programming neural network

In this paper, the problem of phase retrieval is addressed. Its solution is based on the Lagrange programming neural network (LPNN), which is an analog neural computational technique for solving nonlinear constrained optimization problems according to the Lagrange multiplier theory. The local stability of the proposed algorithm is also investigated. Furthermore, we extend the LPNN based approach to more challenging array signal processing applications, namely, when multiple vector signals with full column rank or other constraints are required to be recovered from measured magnitudes. One of the key difficulties for these challenges is pairing the separately estimated parameters, while the parameters estimated by the extended method are automatically paired. The performance of the developed algorithms is demonstrated via computer simulations.

Green synthesis of novel biochar from Abelmoschus esculentus seeds for direct blue 86 dye removal: Characterization, RSM optimization, isotherms, kinetics, and fixed bed column studies

The presence of Direct blue 86 dye (DB86) in water can lead to various health hazards to the humans and animals. The study explored efficacy of biochar derived from Abelmoschus Esculentus seeds (AESB) to remove DB86 from an aqueous solution. BET analysis of AESB delineated H4 classification with the predominance of micropores and mesopores spread throughout the surface. FTIR study demonstrated the presence of the alkyl (C–H), Alkene (C]C), Carbonyl (C]O) and O–H bond of the sulphonic group which helped in adsorption of DB86 molecules through various mechanisms i.e., pore filling, π-π interactions, and hydrogen bonding interactions. Response surface methodology (RSM) was used for designing the adsorption experiment and analysing the optimum operating parameters. Batch experiments demonstrated excellent adsorption capacity (277.04 mg/g) of AESB and was efficient in 98.06% removal of DB86 at optimal conditions i.e., dye conc. = 300 mg/L, dose = 2.5 g/L, pH = 2, time of 120 min. Adsorption followed nonlinear Sips model (R2 = 0.999) with an error (X2 = 0.13, RMSE = 0.83, MAPE 0.56 and MSRE = 0.0006). The kinetic analysis revealed intra-particle diffusion being the rate-determining step and followed nonlinear pseudo-first-order kinetics (R2 = 0.997). Thermodynamic study revealed that the adsorption of DB-86 proceeded spontaneously and exhibited endothermic characteristics, with the enthalpy change primarily governed by the physisorption mechanism. Thomas model revealed inverse relation of breakthrough and exhaustion time with flow while it was proportional to bed height. The sorption capacity (N0) (2.2493 mg/l min) and rate constant (Ka) (0.028 L/min. mg) of BDST model can accurately be used for predicting the performance of AESB in full scale column.

Basalt fibre reinforced polymer bars as main reinforcement of axially compressed concrete column – experimental and numerical considerations of fire resistance

The study aimed to highlight the possibility of achieving satisfactory level of fire resistance in concrete column reinforced with Basalt Fibre Reinforced Polymer (BFRP) bars as a main reinforcement.The literature data [1] of steel reinforced columns was used for preliminary validation of the numerical model. Full scale BFRP-reinforced column was analyzed experimentally and numerically along with experimental evaluation of thermo-mechanical parameters of the BFRP bars and concrete.Fire resistance of the element was calculated by means of numerical simulation, as the time when further sustaining of the mechanical load was no longer possible. The Concrete Damaged Plasticity (CDP) model for concrete was used.The model appeared to be effective in predicting fire resistance of concrete columns with steel reinforcement with various spacings of stirrups (differences up to 12%). In terms of element reinforced with BFPR, the fire resistance of the column tested was about 30% higher than the numerically determined value. Also, the calculated temperatures were compared to values measured by means of thermocouples. Finally, the possibility of achieving over 3 h of fire resistance for columns with BFRP main reinforcement has been proven in both – numerical and experimental investigations.

Application of a hyperspectral camera for in situ plasma-material interaction studies at the linear plasma device PSI-2.

A hyperspectral camera (HSC-type Specim IQ) has been applied at the linear plasma device PSI-2 under steady-state conditions. The camera has the capacity of hyperspectral imaging (HSI) with the dimension of a data array 512 × 512 × 204 (x, y, λ) covering the spectral span from 400 to 1000nm with moderate average spectral resolution (FWHM ∼7nm). After radiometric calibration and background/continuum emission subtraction, two main applications of the camera, (i) plasma diagnostics in helium (He) plasmas and (ii) plasma-material interaction studies with tungsten (W) targets in neon (Ne) plasmas, have been carried out. The measurements were complemented by a movable Langmuir double probe system (LP) measuring electron temperature (Te) and electron density (ne) in radial direction r and a fiber-coupled cross-dispersion spectrometer with high spectral resolution (Spectrelle) recording neutral He, W, and Ne emission lines over the full plasma column. (i) Two-dimensional (2D) imaging of Te and ne radial profiles in axial direction z of the He plasma column were for the first time obtained by the regression analysis of Te and ne (from LP) and six He I line ratios (from HSC). The spatially resolved plasma parameters covered in these studies range between Te ∼ 0.8-13.4eV and ne ∼ 0.2 × 1018-3.9 × 1018m-3 and permit a reconstruction of the plasma conditions in PSI-2 in 2D without LP perturbation. (ii) W sputtering was studied in situ in Ne plasmas exposing W target samples (negatively biased at 100V) under perpendicular Ne plasma impact. Simultaneously, the 2D distributions of W (W I line at 429.5nm) in front of the target and the 2D Ne plasma distribution (Ne I line at 703.2nm) were recorded with complete spectral separation as confirmed by the Spectrelle spectrometer. This permits the simultaneous measurement of the neutral W penetration and its angular distribution induced in the sputtering process and of the impinging plasma distribution. The HSI technique offers, despite a few technical drawbacks, such as the moderate spectral resolution and poor time resolution, a new possibility to distinguish multiple emission lines from plasma and impurities and complements the portfolio of existing Optical Emission Spectroscopy techniques, providing a good compromise regarding spectral, spatial, and temporal resolution.

Control of faults and fractures on shale oil enrichment

The Qingshankou Formation is the primary shale oil exploration and development target in the Songliao Basin, but controlling factors of shale oil enrichment, especially the role of faults and fractures, are still poorly understood. We identify fault geometry in the Qingshankou Formation based on seismic interpretation. We characterize natural fractures with outcrop and core observations, and thin-sections petrography. By integrating faults and fracture observations at various scales, tectonic history of the basin, and burial history of the studied reservoir formation, we explain the control of faults and fractures on shale oil enrichment. Results show that high-density fault systems, namely “T11″ and “T2″ fault systems, were developed at the top and bottom of Qingshankou Formation in the north of Songliao Basin. Both fault systems is characterized as a group of high-density, closely spaced small faults forming a fault belt, with evident multi-stage activities. Nature fracture categories identified including folding and faulting related fractures, bed-parallel fractures and overpressure fractures, while the former two are better developed. Tectonic movements have caused the structural uplift and subsidence to take place at different times in different parts of the basin. The structural uplift happened late in the study area, consequently the source rocks have gone through a long burial history and are well matured, which favors shale oil enrichment. Tectonic uplifts generated large numbers of fractures locally, effectively increase oil production by improving the migration pathways and storage space of shale oil. Fault systems of different scale also provided two-way channels for oil migration in Qingshankou Formation. Large-scale faults that cut through the full shale column allow the shale oil to migrate to the conventional reservoirs above and below the Qingshankou Formation. The smaller faults in the high-density fault belt within the Qingshankou Formation (Qing-1 Member) enhanced seepage capacity and connectivity of the shale reservoir. As a result, shale oil and conventional oil development in the study area can collaborate with one another. High-density, well connected natural fractures also played an important role by providing storage space and fluid flow conduit which is essential in shale oil reservoirs. However, these fractures along faults may migrate oil from shale reservoirs to neighboring conventional reservoirs.

Constructing solutions of the Yang–Baxter-like matrix equation for singular matrices

Let A=UVH be an n×n complex singular matrix of rank r, where U, V are two n×r matrices of full column rank. Some sufficient and necessary conditions are derived for X being a nontrivial (commuting) solution of the quadratic matrix equation AXA=XAX such that we can construct infinitely many (commuting) solutions of the matrix equation. When VHU is nonsingular, all the solutions of the matrix equation are characterized and can be found and constructed by solving smaller matrix equations. In particular, all the commuting solutions can be obtained by finding the projections that commute with VHU. The method of constructing the solutions is free of computations of Jordan canonical forms and matrix inverses.

Globally optimal distributed and sequential state fusion filters for multi-sensor systems with correlated noises

The problem concerning the multi-sensor fusion filtering for systems with correlated system and measurement noises is studied in this paper. Each sensor produces a local predictor by using its own measurements and then sends it to a fusion center. In the fusion center, by applying the projection theory and difference technology, the globally optimal distributed state fusion filter without feedback and sequential state fusion filter with recursive estimators of noises are presented in the sense of linear minimum variance by using all received local predictors, respectively. Under the condition that local prediction gain matrices are of full column rank, the proposed distributed and sequential state fusion filters can achieve the same estimation accuracy as the centralized fusion filter, i.e., they both have global optimality. The optimality is strictly proved. The corresponding steady-state fusion filters are also explored. A sufficient condition for the convergence of the proposed fusion filters is given. A target tracking example verifies the effectiveness of the proposed algorithms.