Abstract
Geophysical subsurface characterization plays a key role in the success of geologic carbon sequestration (GCS). While deterministic inversion methods are commonly used due to their computational efficiency, they often fail to adequately quantify the model uncertainty, which is essential for informed decision-making and risk mitigation in GCS projects. In this study, we propose the SVGD-AE method, a novel geostatistical inversion approach that integrates geophysical data with prior geological knowledge to estimate subsurface properties. SVGD-AE combines Stein Variational Gradient Descent (SVGD) for sampling high-dimensional distributions with an autoencoder (AE) neural network for re-parameterizing reservoir models, aiming to accurately preserve geologic characteristics of reservoir models derived from prior knowledge. Through a synthetic example of pre-stack seismic inversion, we demonstrate that the SVGD-AE method outperforms traditional probabilistic methods, particularly in inverse problems with complex posterior distributions. Then, we apply the SVGD-AE method to the Illinois Basin—Decatur Project (IBDP), a large-scale CO2 storage initiative in Decatur, Illinois, USA. The resulting petrophysical models with quantified uncertainty enhance our understanding of subsurface properties and have broad implications for the feasibility, decision making, and long-term safety of CO2 storage at the IBDP.
Abstract
Quantitative understanding of the land water loading is a prerequisite to the construction of reliable tectonic deformation velocity field in the Tibetan Plateau (TP). Here, for the first time, we image the three-dimensional crustal loading deformation velocity field of each land water component in the TP. Our results reveal that the loading signal strength of the six land water components ranks from largest to smallest as groundwater, glacier, lake, soil water, permafrost, and snow, with the maximum vertical velocity close to ±1.60 mm/yr and the maximum horizontal velocity exceeding 0.40 mm/yr. All land water components can achieve a strong enough vertical loading velocity exceeding the present-day Global Positioning System (GPS) velocity at some sites. But for horizontal loading, apparent impacts are only from glacier, lake and groundwater, however, are very limited, with the absolute ratio of loading velocity to GPS velocity being smaller than 5% at almost all the sites.
Abstract
Near-term projections of drought in the southwestern United States (SWUS) are uncertain. The observed decrease in SWUS precipitation since the 1980s and heightened drought conditions since the 2000s have been linked to a cooling sea surface temperature (SST) trend in the Equatorial Pacific. Notably, climate models fail to reproduce these observed SST trends, and they may continue doing so in the future. Here, we assess the sensitivity of SWUS precipitation projections to future SST trends using a Green's function approach. Our findings reveal that a slight redistribution of SST leads to a wetting or drying of the SWUS. A reversal of the observed cooling trend in the Central and East Pacific over the next few decades would lead to a period of wetting in the SWUS. It is critical to consider the impact of possible SST pattern trends on SWUS precipitation trends until we fully trust SST evolution in climate models.
Abstract
To investigate the impact of CO2-rich fluids on compaction behaviors and transport properties in carbonate fault zones, we conducted compaction-coupled fluid flow experiments with CO2-rich fluids percolating precompacted calcite aggregates. Our findings reveal distinct responses among samples subjected to different fluid conditions. Specifically, samples exposed to dry conditions exhibited negligible compaction strain, while those under wet-closed conditions displayed relatively minor strain. In contrast, samples subjected to flow-through conditions demonstrated significant compaction strain, with strain rates higher by 2–3 orders of magnitude than closed conditions due to enhanced pressure solution, subcritical cracking, and chemical dissolution. Strain rate, permeability, and grain size distribution exhibited spontaneous variations in response to fluid flow and compaction. Microstructures and mechanical and transport data suggest that deformation during the initial infiltration of CO2-rich fluids was dominated by subcritical cracking, followed by pressure solution as grain size evolved, which resulted in compaction and reduced permeability. The persistent infiltration of CO2-rich fluids further enhanced inhomogeneous dissolution-precipitation with preferred dissolution channels serving as fluid pathways. The re-precipitations may cement fault rocks and form low permeability seals, resulting in anisotropic fluid flow and localized fluid pressure in fault zones. As applied to nature, our results provide experimental evidence for the evolution of internal structures and transport behaviors, shedding important light on the mechanisms and sealing potential of carbonate faults in response to the infiltration of CO2-rich fluids during the post-seismic and inter-seismic processes.
Abstract
This study presents a recent finding of magnetic shelf structures and packages of whistler-mode waves in the data obtained from the Magnetospheric Multiscale (MMS) mission satellite in the equatorial magnetosphere. These observations are compared with the waves observed on density shelves by the NASA Van Allen Probes (aka RBSP) mission. By employing simulations of the electron-MHD model, we explain that similar to the density shelf ducting, magnetic shelves effectively guide whistler-mode waves along the ambient magnetic field with little attenuation. The parameters of the guided waves depend on the parameters of the shelves. We discuss the similarities and differences of the wave guided by the density and magnetic field shelf-like structures. The simulations successfully reproduce the parameters of the observed waves.
Brief communication: Lessons learned and experiences gained from building up a global survey on societal resilience to changing droughts
Marina Batalini de Macedo, Marcos Roberto Benso, Karina Simone Sass, Eduardo Mario Mendiondo, Greicelene Jesus da Silva, Pedro Gustavo Câmara da Silva, Elisabeth Shrimpton, Tanaya Sarmah, Da Huo, Michael Jacobson, Abdullah Konak, Nazmiye Balta-Ozkan, and Adelaide Cassia Nardocci
Nat. Hazards Earth Syst. Sci., 24, 2165–2173, https://doi.org/10.5194/nhess-24-2165-2024, 2024
With climate change, societies increasingly need to adapt to deal with more severe droughts and the impacts they can have on food production. To make better adaptation decisions, drought resilience indicators can be used. To build these indicators, surveys with experts can be done. However, designing surveys is a costly process that can influence how experts respond. In this communication, we aim to deal with the challenges encountered in the development of surveys to help further research.
The impact of long-term changes in ocean waves and storm surge on coastal shoreline change: a case study of Bass Strait and south-east Australia
Mandana Ghanavati, Ian R. Young, Ebru Kirezci, and Jin Liu
Nat. Hazards Earth Syst. Sci., 24, 2175–2190, https://doi.org/10.5194/nhess-24-2175-2024, 2024
The paper examines the changes in shoreline position of the coast of south-east Australia over a 26-year period to determine whether changes are consistent with observed changes in ocean wave and storm surge climate. The results show that in regions where there have been significant changes in wave energy flux or wave direction, there have also been changes in shoreline position consistent with non-equilibrium longshore drift.
An easy-to-use water vapor sampling approach for stable isotope analysis using affordable membrane valve multi-foil bags
Adrian Dahlmann, John D. Marshall, David Dubbert, Mathias Hoffmann, and Maren Dubbert
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-43,2024
Preprint under review for AMT (discussion: open, 0 comments)
Water-stable isotopes are commonly used in hydrological and ecological research. Until now, measurements were obtained either destructive or directly in the field. Here, we present a novel, affordable, and easy-to-use approach to measure the stable isotope signatures of soil water. Our gas bag approach demonstrates a high accuracy and extends the usability by allowing water vapor samples to be collected and stored in the field without the need for an instrument or a permanent power supply.
Lidar–radar synergistic method to retrieve ice, supercooled water and mixed-phase cloud properties
Clémantyne Aubry, Julien Delanoë, Silke Groß, Florian Ewald, Frédéric Tridon, Olivier Jourdan, and Guillaume Mioche
Atmos. Meas. Tech., 17, 3863–3881, https://doi.org/10.5194/amt-17-3863-2024, 2024
Radar–lidar synergy is used to retrieve ice, supercooled water and mixed-phase cloud properties, making the most of the radar sensitivity to ice crystals and the lidar sensitivity to supercooled droplets. A first analysis of the output of the algorithm run on the satellite data is compared with in situ data during an airborne Arctic field campaign, giving a mean percent error of 49 % for liquid water content and 75 % for ice water content.
Catchment-scale assessment of drought impact on environmental flow in the Indus Basin, Pakistan
Khalil Ur Rahman, Songhao Shang, Khaled Saeed Balkhair, Hamza Farooq Gabriel, Khan Zaib Jadoon, and Kifayat Zaman
Nat. Hazards Earth Syst. Sci., 24, 2191–2214, https://doi.org/10.5194/nhess-24-2191-2024, 2024
This paper assesses the impact of drought (meteorological drought) on the hydrological alterations in major rivers of the Indus Basin. Threshold regression and range of variability analysis are used to determine the drought severity and times where drought has caused low flows and extreme low flows (identified using indicators of hydrological alterations). Moreover, this study also examines the degree of alterations in river flows due to drought using the hydrological alteration factor.
Hydrometeorological controls of and social response to the 22 October 2019 catastrophic flash flood in Catalonia, north-eastern Spain
Arnau Amengual, Romu Romero, María Carmen Llasat, Alejandro Hermoso, and Montserrat Llasat-Botija
Nat. Hazards Earth Syst. Sci., 24, 2215–2242, https://doi.org/10.5194/nhess-24-2215-2024, 2024
On 22 October 2019, the Francolí River basin experienced a heavy precipitation event, resulting in a catastrophic flash flood. Few studies comprehensively address both the physical and human dimensions and their interrelations during extreme flash flooding. This research takes a step forward towards filling this gap in knowledge by examining the alignment among all these factors.
Improving ensemble data assimilation through Probit-space Ensemble Size Expansion for Gaussian Copulas (PESE-GC)
Man-Yau Chan
Nonlin. Processes Geophys., 31, 287–302, https://doi.org/10.5194/npg-31-287-2024, 2024
Forecasts have uncertainties. It is thus essential to reduce these uncertainties. Such reduction requires uncertainty quantification, which often means running costly models multiple times. The cost limits the number of model runs and thus the quantification’s accuracy. This study proposes a technique that utilizes users’ knowledge of forecast uncertainties to improve uncertainty quantification. Tests show that this technique improves uncertainty reduction.
Multi-dimensional, Multi-Constraint Seismic Inversion of Acoustic Impedance Using Fuzzy Clustering Concepts
Saber Jahanjooy, Hosein Hashemi, and Majid Bagheri
Nonlin. Processes Geophys. Discuss., https//doi.org/10.5194/npg-2024-12,2024
Preprint under review for NPG (discussion: open, 3 comments)
This manuscript introduces a new method of using the objective function of fuzzy clustering in seismic inversion. Multiple constraints on the data misfit, allow the operator to apply different conditions on the results. The solution is simple. New concepts that are the results of the inversion methods are good sources for interpretation.
Observations of ionospheric disturbances associated with the 2020 Beirut explosion by Defense Meteorological Satellite Program and ground-based ionosondes
Rezy Pradipta and Pei-Chen Lai
Ann. Geophys., 42, 301–312, https://doi.org/10.5194/angeo-42-301-2024, 2024
A large explosion released a significant amount of energy into the Earth's upper atmosphere in Beirut on 4 Aug 2020, generating traveling ionospheric disturbances (TIDs). These TIDs were observed in previous work using GPS total electron content measurements around Beirut. Here, we used measurements from the Defense Meteorological Satellite Program and ionosondes in the Mediterranean to show that the TIDs from the Beirut explosion were able to reach greater distances than previously reported.
Abstract
Along the I24, I27, and I31 flybys of Io (1999–2001), the Energetic Particle Detector (EPD) onboard the Galileo spacecraft observed localized regions of energetic protons losses (155–1,250 keV). Using back-tracking particle simulations combined with a prescribed atmospheric distribution and a magnetohydrodynamics (MHD) model of the plasma/atmosphere interaction, we investigate the possible causes of these depletions. We focus on a limited region within two Io radii, which is dominated by Io's SO2 atmosphere. Our results show that charge exchange of protons with the SO2 atmosphere, absorption by the surface and the configuration of the electromagnetic field contribute to the observed proton depletion along the Galileo flybys. In the 155–240 keV energy range, charge exchange is either a major or the dominant loss process, depending on the flyby altitude. In the 540–1,250 keV range, as the charge exchange cross sections are small, the observed decrease of the proton flux is attributed to absorption by the surface and the perturbed electromagnetic fields, which divert the protons away from the detector. From a comparison between the modeled losses and the data we find indications of an extended atmosphere on the day/downstream side of Io, a lack of atmospheric collapse on the night/upstream side as well as a more global extended atmospheric component (>1 Io radius). Our results demonstrate that observations and modeling of proton depletion around the moon constitute an important tool to constrain the electromagnetic field configuration around Io and the radial and longitudinal atmospheric distribution, which is still poorly understood.
Abstract
The statistics of day-to-day tidal variability within 35-day running mean windows is obtained from Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI)/Ionospheric Connection Explorer (ICON) observations in the 90–107 km height region for the year 2020. Temperature standard deviations for 18 diurnal and semidiurnal tidal components, and for four quasi-stationary planetary waves are presented, as function of latitude, altitude, and day-of-year. Our results show that the day-to-day variability (DTDV) can be as large as 70% of the monthly mean amplitudes, thus providing a significant source of variability for the ionospheric E-region dynamo and hence for the F-region plasma. We further validate our results with COSMIC-2 ionospheric observations and present an approach to extend the MIGHTI/ICON results to all latitudes using Hough Mode Extension fitting, to produce global tidal fields and their statistical DTDV that are suitable as lower boundary conditions for nudging and ensemble modeling of TIE-GCM. In the future, this will likely help to establish a data-driven perspective of space weather variability caused by the tidal weather of the lower atmosphere.
Abstract
The Earth's magnetosphere is filled with a collisionless plasma that exhibits non-Maxwellian particle distributions which are well described by Kappa functions. In contrast to the Maxwellian, the Kappa contains not only density and temperature but also the kappa index that allows us to characterize the energetic tails. In this study, we analyze the response of the ion and electron Kappa distributions, obtained by fitting ion and electron fluxes measured by the five THEMIS satellites, to changes of the solar wind dynamic pressure. It was found that the solar wind dynamic pressure strongly affects the values of the kappa index, and that its impact depends on the magnetic local time (MLT). In particular, there is a significant dawn-dusk asymmetry for low P
SW
values which is enhanced in the night side. Further, we observe a narrow partial ring-shaped structure at different azimuthal extension that divides the plasma into two clearly defined domains. The results obtained reflect the global reconfiguration of the magnetosphere caused by variations of the solar wind dynamic pressure. Kappa distribution parameters and their average values for different ranges of P
SW
and MLT are provided, which we believe will contribute as realistic inputs to the modeling of the magnetosphere.
Abstract
In the present study, the influence of the solar wind dynamic pressure on the plasma and magnetic pressures of the magnetosphere is studied. We use 11-year Time History of Events and Macroscale Interactions during Substorms (THEMIS) instruments for plasma and magnetic field measurements in the magnetosphere and the OMNI database for solar wind dynamic pressure and IMF data. We focus on the effects of the solar wind dynamic pressure (P
SW
) and consider only times in which the interplanetary magnetic field (IMF) components are within ±5 nT. We find that the plasma pressure inside the magnetosphere follows the solar wind dynamic pressure and that an increase in P
SW
also influence the day-night pressure asymmetry. Our analysis also reveals the existence of ion and electron drifts from midnight toward the dusk and dawn sectors, respectively. We observe a local magnetic pressure minimum located near a plasma pressure maximum at around 11 R
E
on the nightside. Comparing the effect of P
SW
on both plasma and magnetic pressures, we observe trends which are consistent with the diamagnetic properties of plasmas. In general, the distribution of plasma pressure within the Earth's magnetosphere is an important criterion for evaluating the magnetostatic equilibrium and electric current system. The outcome of this study should provide additional methodologies for the characterization of key plasma characteristics within the magnetosphere.
Abstract
Andean glaciers are losing mass rapidly but a centennial-scale context to those rates is lacking. Here we show the extent of >5,500 glaciers during the Little Ice Age chronozone (LIA; c. 1,400 to c. 1,850) and compute an overall area change of −25% from then to year 2000 at an average rate of −36.5 km2 yr−1 or −0.11% yr−1. Glaciers in the Tropical Andes (Peru, Bolivia) have depleted the most; median −56% of LIA area, and the fastest; median −0.16% yr−1. Up to 10 × acceleration in glacier area loss has occurred in Tropical mountain sub-regions comparing LIA to 2,000 rates to post-2000 rates. Regional climate controls inter-regional variability, whereas local factors affect intra-region glacier response time. Analyzing glacier area change by river basins and by protected areas leads us to suggest that conservation and environmental management strategies should be re-visited as proglacial areas expand.
Abstract
The characteristics of the Madden–Julian oscillation (MJO) have changed and are projected to continue changing with the expansion of the Indo–Pacific warm pool, which is the Earth's largest region of warm sea surface temperatures (SSTs). However, the likelihood of a change in MJO predictability following warm pool expansion remains unaddressed. Therefore, this study investigated the effect of warm pool expansion on MJO variability and predictability using the highly idealized aquaplanet configuration of Community Earth System Model 2 (CESM2). By expanding the warm pool in the Indo–Pacific, MJO-like waves become more regionally confined, short-lived convective events with weaker magnitude and less robust eastward propagating signals, possibly due to stronger zonal SST gradients and wider meridional widths of the warm pool. Perfect-model ensemble forecast experiments revealed that the MJO predictability decreased by approximately 5 days, the forecast error proliferated, and the signal rapidly reduced following warm pool expansion.
