UNAVCO and IRIS, major repositories for global geodetic and seismic data, are in the process of joining their operations to form a unified facility for supporting the broad spectrum of geophysical observations and science required to help understand and predict the behavior of Earth Systems. This process would be complicated in a static data management environment, but both repositories are also migrating archives and services to the cloud as part of the merger. To simplify and unify archive data management, the organizations are collaborating to create common data and metadata models for observations from a wide variety of instruments and disciplines. For data, the initial focus has been on the xArray data model, already used in the geodetic and magnetotelluric communities, which can be implemented with several disc- and cloud-native approaches (HDF5, netCDF4, and Zarr). For metadata, the SensorML Standard developed by the Open Geospatial Consortium is being explored because 1) SensorML accommodates the large parameter space associated with instrument metadata required to use and trust complex observations and 2) the ability to extend the standard when required. The merger of two large repositories combined with migration to the cloud requires careful identification and on-going testing of a wide variety of assumptions about data management systems. This presentation will focus on lessons learned so far.

The properties of the auroral electrojets are studied by modeling the relationships between the solar-wind parameters and the AU and AL indices with a trained echo state network (ESN), a kind of recurrent neural network. To identify the properties of auroral electrojets, we obtain various synthetic AU and AL data by using various artificial inputs with the trained ESN. The synthetic data show that the AU and AL indices are significantly affected by the solar-wind speed in addition to Bz of the interplanetary magnetic field (IMF). A contributions from IMF By is are also suggested. In addition, the synthetic data indicate nonlinear effects from the solar-wind density, which is strong when the solar-wind speed is high and when IMF Bz is near zero.

Dynamical models used in climate prediction often suffer from systematic errors that can deteriorate their predictions. We propose a hybrid model that combines both dynamical model and artificial neural network (ANN) correcting model errors to improve climate predictions. We conducted a series of experiments using the Modular Arbitrary-Order Ocean-Atmosphere Model (MAOOAM) and trained the ANN with input from both atmospheric and oceanic variables and output from analysis increments. Our results demonstrate that the hybrid model outperforms the dynamical model in terms of prediction skill for both atmospheric and oceanic variables across different lead times. Furthermore, we conducted additional experiments to identify the key factors influencing the prediction skill of the hybrid model. We found that correcting both atmospheric and oceanic errors yields the highest prediction skill while correcting only atmospheric or oceanic errors has limited improvement.

We investigate the conditions under which saucer-shaped sills form through the upper crust and their geometries. We performed a series of scaled laboratory experiments that employ visco-elastic-plastic Laponite RD® (LRD) gels to model upper crustal rocks, and Newtonian paraffin oil as the magma analogue. Both homogenous and layered analogue upper crust is considered. In homogenous 3 wt. % LRD, the injected oil formed a saucer-shaped intrusion with the shortest inner sill observed among all of the experiments. Saucer-shaped sills always formed in experiments with a two-layer upper crust. These experiments show sharp transitions from an inner flat sill to outer inclined sheets, which are characterised by non-planar margins. The experimental results show that: (1) the transition from an inner flat sill to outer inclined sheet occurs when the sill radius to overburden depth ratio (r/H) is between 0.5 and 2.5; (2) the inclined sheets propagate upwards with angles, θ = 15° to 25°; (3) the ratio of the Young’s modulus (E*) between the layers controls when the inner flat sill to outer inclined sheet occurs; and (4) irregular finger-like and/or lobe segment geometries form at the propagating tip of the intrusion. The results also suggest that there is no strict requirement for high horizontal stresses to form natural saucer-shaped sill geometries. We conclude that the layered visco-elastic-plastic crustal analogues better represent natural, complex saucer-shaped sill geometries. Furthermore, the observed sharp transitions between inner and outer sills are compatible with brittle-elastic fracture mechanisms operating at the intrusion scale.

Serpentinization of ultramafic rocks is fundamental to modern plate tectonics and for volatile (re-)cycling into the mantle and magmatic arcs. Serpentinites are also highly reactive with CO2 such that they are prime targets for carbon sequestration. Serpentinization and carbonation of ultramafic rocks results in changes in their physical properties such that they should be detectable using geophysical surveys; this could provide constraint on the reactivity of rocks without extensive sample characterization. We constrain the physio-chemical relationships in altered ophiolitic ultramafic rocks using petrographic observations, major-element chemistry, quantitative X-ray diffraction, and physical properties on a suite of >400 samples from the Canadian Cordillera. Serpentinization results in a systematic decrease in density that reflects the increase in serpentine abundance and carbonation results in an increase in density, mostly reflecting the formation of magnesite; based on these data we present two formulations for determining extent of serpentinization: one based on major-element chemistry and the other on density. Magnetic susceptibility is variable during serpentinization; most harzburgitic samples show a 100-fold increase in magnetic susceptibility, whereas most dunitic samples and a minor proportion of harzburgitic samples show very little change in magnetic susceptibility. We use quantitative mineralogy and physical properties of the samples to constrain a model for using density and magnetic susceptibility to approximate the mineralogy of ultramafics rock. Although further work is required to understand the role of remanence in applying these models to geophysical data, this presents an advancement and opportunity to prospect for the most reactive ultramafic rocks for carbon sequestration.

The focus here is on the Earth’s planetary albedo estimates derived from the data of Earth Polychromatic Imaging Camera (EPIC) onboard NOAA’s Deep Space Climate Observatory (DSCOVR). The estimates indicate a short-lived albedo surge with an instantaneous value of $0.350$ on the 5th of December 2020 and a 5-day average above $0.330$. A numerical weather prediction model-based (OpenIFS of ECMWF) estimate confirms the EPIC-based maximum in December 2020 but remains notably lower (maximum at $0.327$). The discrepancy may be explained by the Earth–Satellite–Sun geometry since the DSCOVR satellite was very near the Lagrange point L1 and received the Earth outgoing short-wave radiation close to backscattering. In this conditions, the angular distribution model based on Clouds and the Earth’s Radiant Energy System (CERES) and the associated footprint identification are prone to uncertainties.

We conducted field work on the shoals of South San Francisco Bay to elucidate the mechanisms driving cohesive sediment erosion in a shallow, wave- and current-driven flow. Compiling data from three deployments, including measurements taken within the combined wave-current boundary layer, we found that waves were strongly correlated to turbulent sediment fluxes across all seasons and a range of deployment depths. Tidal turbulence was only correlated to turbulent sediment fluxes for larger relative depths, or when a wave-driven sediment flux into the boundary layer allowed the tidal shear stress to transport sediment into the overlying flow. Despite the dominance of waves in eroding sediment, we found favorable agreement between in situ boundary layer erosion measurements and laboratory erosion measurements conducted in a steady flume. Results were analyzed in the context of two benthic surveys which provided insight into the sediment bed properties.

Dense seismic array monitoring on glaciers combined with advanced array processing may help retrieve and locate a variety of seismic sources with unprecedented resolution and spatial coverage. Here we present an array methodology that goes beyond classical localization algorithms through gathering various types of sources (impulsive or continuous) into a single scheme and sort those by their associated array phase coherence. We demonstrate that we can retrieve the spatial and temporal dynamics of active crevasses with a metric resolution using sources with high phase coherence; the presence of diffracting materials trapped in transverse crevasses using sources with moderate phase coherence; and the time evolution of two-dimensional maps of the subglacial water flow drainage system using sources with low phase coherence. With the ongoing increased use of dense seismic arrays, our study highlights the strength of using an appropriate seismological and statistical approach to image a wide range of subsurface structures.

In spite of many specific studies focussing on the Sea of Marmara segment of the North Anatolian Fault (NAF), its deformation and stress accumulation pattern remain difficult to understand. In part this is due to the complexity of the transform fault system which here combines a releasing and restraining bend. In this study, we use analogue modelling to reproduce and monitor the strain patterns across a releasing and restraining bend pair. We also compare the strain evolution with the evolution of topographic changes. The experiments reveal how the master right-lateral strike-slip fault system and newly formed fault zones change their geometry as displacement accumulates across a releasing and restraining bend pair. We find that the master shear zone develops from a single to a multi-branch fault system, with different branches active and dominant at different times. Comparison with the tectonic setting of the Sea of Marmara suggests that the western portion of the basin may be characterized by a fault shortcut associated with both a compressional regime and uplift of the Ganos Mountain.

Both magmatic and tectonic processes contribute to the formation of volcanic continental margins. Such margins are thought to undergo extension across a narrow zone of lithospheric thinning (~100 km). New observations based on existing and reprocessed data from the Eastern North American Margin contradict this hypothesis. With ~64,000 km of 2D seismic data tied to 40 wells combined with published refraction, deep reflection, receiver function and onshore drilling efforts, we quantified along-strike variations in the distribution of rift structures, magmatism, crustal thickness, and early post-rift sedimentation under the shelf of Baltimore Canyon trough (BCT), Long Island Platform and Georges Bank Basin (GBB). Results indicate that BCT is narrow (80-120 km) with a sharp basement hinge and few rift basins. The Seaward Dipping Reflectors (SDR) there extend ~50 km seaward of the hinge line. In contrast, the GBB is 30 wide (~200 km), has many syn-rift structures, and the SDR there extend ~ 200 km seaward of the hinge line. Early post-rift depocenters at the GBB coincide with thinner crust suggesting “uniform” thinning of the entire lithosphere. Models for the formation of volcanic margins do not explain the wide structure of the GBB. We argue that crustal thinning of the BCT was closely associated with late-syn rift magmatism whereas the broad thinning of the GBB segment predated magmatism. Correlation of these variations to crustal terranes of different compositions suggests that the inherited rheology determined the pre-magmatic response of the lithosphere to extension.

The backflow plume from an electric thruster can lead to the accumulation of electrostatic charge on the spacecraft, leading to a negative charge. Interactions between the plume and solar wind can further influence the charge distribution, resulting in variations in spacecraft potential and interference with sensitive instruments. A 3D Particle-In-Cell (PIC) simulation tool within the Spacecraft Plasma Interaction Software (SPIS) is used to compute spacecraft charging effects from 0.067 to 1 Astronomical unit (AU). The study examines the dynamic behaviour of ambient electrons and ions, thruster electrons, and CEX-ions, as well as photoemission and secondary electrons, and solar photon flux impact on the spacecraft potential. The main finding is the demonstration that the high dominance of CEX-ions and thruster electrons helps to achieve a low and stable negative potential ranging from -2 to -6 V from 0.067 AU to 1 AU when the thruster is on, as opposed to the varying range of -5 to +9 V with the thruster off. Other findings are that the elimination of photoelectrons or secondary electrons has a comparatively greater impact on spacecraft potential when the thruster is off, as opposed to when the thruster is on. Both CEX-ions and thruster electrons significantly contribute to the mitigation and regulation of spacecraft potential towards a less negative potential in situations where photoemission or secondary electrons are absent or relatively unimportant.

The South China Sea (SCS) is one of the world’s most productive fishing zones. Regionalising the SCS, particularly the understudied southern sector (SSCS), is crucial for improving resource management in the SCS. In this study, we analysed 24 years of satellite-derived chlorophyll-a concentration (CHL) using a combination of empirical orthogonal function and Fuzzy C-mean clustering techniques. Our results reveal that the seasonal variability of CHL can be divided into three distinct regions. Broadly, these regions separate into the eastern and western basins. The first region encompasses the eastern boundary of the SSCS, the second region includes the area off the coast of Vietnam, and the central SSCS, while the third region extends from Karimata Straits to the Mekong River mouth. Each region exhibits unique seasonal CHL patterns: the first region shows a unimodal seasonality, while the second and third regions display bimodal seasonality. Beyond the climatological occupancy of these regions, we also demonstrate that their spatial extent is temporally dynamic. Regions can expand, contract, or shift entirely on an interannual scale. For instance, during the 1998 El Niño event, CHL variability in the deep basin experienced a marked changed due to intense warming. In contrast, during the 2015 El Niño event, despite similarly intense warming, CHL variability was statistically consistent with climatological norms. While the modulation of monsoonal winds by El Niño Southern Oscillation partially explains the interannual variability in the region. Our findings suggest that this variability is highly complex, likely due to the dynamic nature of the basin.

Modeling forest propagation loss over a vast area is challenging, particularly for the hilly terrain regions where canopy obstacle depth varies with region. To consider such vegetation impact, we present a novel forest cover classification well-defined with the line-of-sight (LoS). Furthermore, we incorporated the mobile antenna site elevation angle, which showed significant influence within the target frequencies selected at 182.25 MHz 15 and 203.25 MHz (VHF Band III). We proposed a loss exponent dependent on the elevation angle and the vegetation-visibility classification, which is the basis of the model introduced in this paper. The resulting loss derived using this loss exponent showed a good agreement with the empirically derived loss variations. The proposed method offers an easy forest classification approximations with precise determination of signal variation over a wide-ranging forested area.

Subsurface remediation of groundwater and soils contaminated by chlorinated ethenes is a challenge as many sites remain with contaminant concentrations above regulatory limits. One issue that prevents site restoration is back diffusion of contaminants from low permeable layers into transmissive layers, which sustains contaminant plumes. In our research, we develop a two-dimensional analytical model of an aquifer-aquitard system which employs temporally variable boundary conditions to investigate the sensitivity of mass discharge across a downgradient control plane (DGCP) to both the mass discharge behavior from dense nonaqueous phase liquid source zones (i.e., the source-strength function or SSF) and contaminant mass stored in the aquitard. Existing models usually assume constant concentration boundary conditions which are not always representative of actual field conditions, especially when those boundary conditions are meant to represent the SSF. Modeling results are used to explore aquitard source functions, defined as the relationship between mass discharge across the DGCP and mass stored in the upgradient aquitard. We also explore the benefits associated with partial removal of DNAPL mass from the source zone, as well as the impacts of when those efforts occur in the lifetime of the source zone by testing the sensitivity of mass stored in the aquitard and mass discharge across a DGCP to different remediation scenarios. In instances where complete remediation is impractical, it is important for remediation managers (and other stakeholders) to know the options and expected results for partial remediation in the short term. Moreover, results are used to assess the relative importance of addressing contaminant mass in the DNAPL source zone versus the aquitard as the contaminant site ages. Finally, we explore a methodology for estimating contaminant mass in the aquitard with time, as a function of the SSF and mass discharge across a DGCP. This methodology complements site characterization efforts, especially at complex sites where detailed sampling of low permeable layers is a challenge.

It is now known that many spiral density waves in Saturn’s C ring are forced by resonant gravitational interactions with the planet’s nonradial oscillations. Observations of their periods have the power to reveal new information concerning subtle aspects of the planet’s internal structure. The properties of a certain class of nonradial oscillations, consisting of the inertial and rotational normal modes (i-modes and r-modes), are particularly sensitive to small departures of the internal density stratification from adiabatic, and may be especially useful in revealing such departures and their implications for any compositional gradients residing inside Saturn. We calculate the frequencies and eigenfunctions (shapes) of the i-modes and r-modes for a given suite of internal structure models and determine the Lindblad resonance locations and periods of the density waves they excite in the C ring. We find that for reasonable models of Saturn’s internal structure, the i-mode and r-mode frequencies overlap the range of frequencies of the slowest density waves observed in the C ring, that is, those having pattern speeds similar to Saturn’s rotation rate. In addition, the presence of observable density waves forced by r-modes requires Saturn to possess (at least) two statically stable (non-convective) regions, one in the deep interior and the other in the outer molecular hydrogen envelope. The inner zone is most likely stabilized by a significant compositional gradient, the outer zone by a compositional gradient, by baroclinic processes, or both. Unresolved questions remain. Currently, the model predicts that if energy is equipartitioned among the i-modes, then some slow density waves should be detectable at radii inside ~84500 km in the C ring. None have been observed inside this radius. In addition, the source of excitation of the normal modes remains to be identified. We are currently exploring whether they can draw their energy from baroclinic instability in the outer stable zone. These questions will be addressed at length at the meeting. This work is supported by the NASA SSW program.

Mesoscale ocean eddies dramatically impact oceanic material transport, momentum and energy budgets, and large-scale ocean circulation; therefore, reasonably diagnosing their effects is crucial for providing insights into eddy parameterization scheme development. In this work, a Reynolds and coarse-graining hybrid eddy transport diagnostic framework is proposed and applied in the Southern Ocean. Both the isotropic transport coefficient and anisotropic transport tensor are diagnosed and decomposed into contributions from transient and stationary eddies. The tensor can be split into its symmetric and antisymmetric parts, and the symmetric tensor is further diagonalized to analyze the eigenvalues and eigenvectors. We verify that the anisotropic assumption better fits the ocean mesoscale eddy transport process than the isotropic assumption, at least in the Southern Ocean. We place particular emphasis on the transport tensor’s stationary component affected by large-scale topographies, nonconservative processes, and large-scale flow structures and find that its influence is highly anisotropic horizontally and varies vertically. We probe all tensor-related elements that emerge in our hybrid framework, especially the eigenvalues and eigenvectors of the symmetric tensor. We reveal all three configurations of the major and minor eigenvalues that appear in the Southern Ocean, where the one representing vortex filamentation is the most common scenario. In addition, we discover a high randomness of the eigenvectors, which implies the possibility of a semideterministic and semistochastic anisotropic parameterization scheme.

Total Least Squares (TLS) or orthogonal regression is used to remedy attenuation bias in optimal fingerprinting regressions. Consistency properties in multivariate applications require strong assumptions about unobservable variance ratios. Monte Carlo analysis is used herein to examine coefficient biases when the explanatory variables are correlated and have heterogeneous error variances. Ordinary Least Squares (OLS) exhibits the expected attenuation bias patterns which vanish as the noise variances on the explanatory variable disappear. TLS is generally more biased than OLS except under homogeneous noise variances. When the explanatory variables are negatively correlated TLS imparts a large upward bias which gets worse as the noise variance on the explanatory variable gets smaller. In general without specific diagnostic information TLS should not be considered an improvement on OLS and can yield extremely biased coefficients.

Dissolved rare earth elements (REE) and neodymium isotopic compositions (εNd) were intensively used to evaluate water mass mixing and lithogenic inputs in oceans. The South China Sea (SCS) is the largest marginal sea and a key region for reconstructing past hydrological changes in the West Pacific; however, its REE and εNd distribution are still not well established. This study investigated dissolved REE concentration and εNd distribution at four water stations in the northern and central SCS to better constrain the εNd distribution and REE cycle in the SCS. The results show relatively high concentrations of REE in surface seawater due to the terrigenous inputs. Seasonal variability in the middle REE enrichment is observed, suggesting a controlling role of the lateral mixing of water masses in the REE fractionation. The decreased REE concentrations in bottom water are mainly attributed to the re-suspended particle scavenging. Surface seawater εNd varies from -2.8±0.3 to -6.7±0.3, implying a significant modification due to riverine inputs. The intermediate water is characterized by a slightly negative εNd compared to the North Pacific Intermediate Water (NPIW) suggesting a vertical mixing between the intermediate and deep water within the SCS. εNd of deep water shows a narrow range from -3.4±0.3 to -4.2±0.3 (mean value of ~-3.8), supporting the presence of Pacific Deep Water (PDW) in the deep SCS basins nowadays. εNd of deep water in the SCS behaves conservatively along its pathway from the West Pacific to the SCS even though particle scavenging occurs in bottom water.