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The December 2020 earthquake near the Croatian town of Petrinja (magnitude 6.4) was felt in all Croatia and in many places in the neighboring countries, and caused serious damage at the site. A recent Croatian-Hungarian collaboration has analyzed the horizontal and vertical displacements caused by the quake and placed them in a regional geodynamic interpretation frame.

Abstract

In peninsular India, the Deccan Traps record massive, continental-scale volcanism in a sequence of magmatic events that corresponds with the timing of mass extinction at the Cretaceous-Paleogene boundary. Although the Deccan volcanism is linked with the Réunion hotspot, the origin of its periodic magmatic pulses is still debated. We developed a numerical model replicating the geodynamic scenario of the African superplume underneath a moving Indian plate to explore the mechanism of magmatic pulse generation during the Deccan volcanism. Our model results revealed a connection between the Réunion hotspot and the African large low shear-wave velocity province (LLSVP), suggesting that the pulses were produced from a thermochemical plume originated in the lower mantle. The ascending plume had stagnation at 660 km due to phase changes in the transition zone, and its head eventually underwent detachment from the tail under the influence of Indian plate movement to produce sequentially four major pulses (periodicity: 5–8 Ma), each giving rise to multiple secondary magmatic pulses at a time interval of ∼0.15–0.4 Ma. This study sheds a new light on the mechanism of periodic hotspot activities from a global perspective.

Revealing halos concealed by cirrus clouds
Yuji Ayatsuka
Atmos. Meas. Tech., 17, 3739–3750, https://doi.org/10.5194/amt-17-3739-2024, 2024
Many types of halos appear in the sky. Each type of halo reflects the state of the atmosphere; therefore observing them from the ground greatly helps in understanding the state of the atmosphere. However, halos are easily obscured by the contrast of the cloud itself, making it difficult to observe them. This study describes the construction of a sky-color model for halos and a new effective algorithm to reveal halos in images.

Algorithm to retrieve aerosol optical properties using lidar measurements on board the EarthCARE satellite
Tomoaki Nishizawa, Rei Kudo, Eiji Oikawa, Akiko Higurashi, Yoshitaka Jin, Nobuo Sugimoto, Kaori Sato, and Hajime Okamoto
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-100,2024
Preprint under review for AMT (discussion: open, 0 comments)
We developed algorithms to produce JAXA ATLID L2 aerosol products using ATLID L1 data. The algorithms estimate layer identifiers such as aerosol or cloud layers, (2) particle optical properties at 355 nm, (3) particle type identifiers, and (4) planetary boundary layer height. We demonstrated the algorithm performance using the simulated ATLID L1 data and found the algorithm’s capability to provide valuable insights into the global distribution of aerosols and clouds.

Central Asian dust has a significant impact on regional and global climate, and it is crucial for the balance of local ecosystems, socio-economic development, and human health.

The polar regions are critical to understanding climate change due to their significant impact on global weather patterns and sea levels. Traditional methods of measuring sea ice thickness face challenges such as high costs and limited spatial coverage.

In the next upgrade of ECMWF's Integrated Forecasting System (IFS), changes in the ocean wind wave model component will be implemented that improve forecasts.

A doubling of the amount of CO2 in the atmosphere could cause an increase in the average temperature on Earth from 7 to a maximum of 14 degrees. This is shown in the analysis of sediments from the Pacific Ocean off the coast of California, by researchers at NIOZ and the Universities of Utrecht and Bristol. Their results were published in Nature Communications.

Hyper-resolution flood hazard mapping at the national scale
Günter Blöschl, Andreas Buttinger-Kreuzhuber, Daniel Cornel, Julia Eisl, Michael Hofer, Markus Hollaus, Zsolt Horváth, Jürgen Komma, Artem Konev, Juraj Parajka, Norbert Pfeifer, Andreas Reithofer, José Salinas, Peter Valent, Roman Výleta, Jürgen Waser, Michael H. Wimmer, and Heinz Stiefelmeyer
Nat. Hazards Earth Syst. Sci., 24, 2071–2091, https://doi.org/10.5194/nhess-24-2071-2024, 2024
A methodology of regional flood hazard mapping is proposed, based on data in Austria, which combines automatic methods with manual interventions to maximise efficiency and to obtain estimation accuracy similar to that of local studies. Flood discharge records from 781 stations are used to estimate flood hazard patterns of a given return period at a resolution of 2 m over a total stream length of 38 000 km. The hazard maps are used for civil protection, risk awareness and insurance purposes.

The Aral Sea, located in Central Asia, has been shrinking in surface area due to climate change and human activities. This shrinkage has caused a regional ecological crisis, significantly affecting the key ecosystem services in the region.

Researchers from The University of Western Australia have created an experiment to explain the volcanic processes needed to transport green metals from the Earth's interior to its surface.

Author(s): Tian-Xing Hu, Dong Wu, Z. M. Sheng, and J. Zhang

The normal modes, i.e., the eigensolutions to the dispersion relation equation, are the most fundamental properties of a plasma. The real part indicates the intrinsic oscillation frequency while the imaginary part the Landau damping rate. In most of the literature, the normal modes of quantum plasma…

[Phys. Rev. E 109, 065213] Published Mon Jun 24, 2024

Author(s): Meng Lian, Chuang Zhang, Zhaoli Guo, and Jing-Tao Lü

Electrons are the carriers of heat and electricity in materials and exhibit abundant transport phenomena such as ballistic, diffusive, and hydrodynamic behaviors in systems with different sizes. The electron Boltzmann transport equation (eBTE) is a reliable model for describing electron transport, b…

[Phys. Rev. E 109, 065310] Published Mon Jun 24, 2024

Abstract

The prediction of post-sunset equatorial plasma depletions (EPDs), often called ionospheric plasma bubbles, has remained a challenge for decades. In this study, we introduce the Ionospheric Bubble Probability (IBP) model, an empirical model to predict the occurrence probability of EPDs derived from 9 years of CHAMP and 9 years of Swarm magnetic field measurements. The model predicts the occurrence probability of EPDs for a given longitude, day of year, local time and solar activity, for the altitude range of about 350–510 km, and low geographic latitudes of ±45°. IBP has been found to successfully reconstruct the distribution of EPDs as reported in previous studies from independent data. IBP has been further evaluated using 1-year of untrained data of the Ionospheric Bubble Index (IBI). IBI is a Level 2 product of the Swarm satellite mission used for EPD identification. The relative operating characteristics (ROC) curve shows positive excursion above the no-skill line with Hanssen and Kuiper's Discriminant (H&KSS) score of 0.52, 0.51, and 0.55 at threshold model output of 0.16 for Swarm A, B, and C satellites. Additionally, the reliability plots show proximity to the diagonal line with a decent Brier Skill Score (BSS) of 0.249, 0.210, and 0.267 for Swarm A, B, and C respectively at 15% climatological occurrence rate. These tests indicate that the model performs significantly better than a no-skill forecast. The IBP model offers compelling glimpses into the future of EPD forecasting, thus demonstrating its potential to reliably predict EPD occurrences. The IBP model is publicly available.

Abstract

The sequence of events associated with the triggering of energy release during substorm expansion phase onset is still not well-understood. Oberhagemann and Mann (2020b, https://doi.org/10.1029/2019gl085271) proposed a new substorm onset mechanism, where the transition toward parallel proton pressure anisotropy during tail stretching in the late growth phase could trigger a pressure anisotropic ballooning instability. Here we examine the evolution of energetic proton parallel pressure anisotropy at geosynchronous altitudes, seeking evidence in support of the proposed substorm onset mechanism. We use the Geostationary Operational Environment Satellite (GOES) proton flux and magnetometer data combined with substorm onset indicators derived from ground-based magnetometers. Superposed epoch analysis of substorm onset times for 2014 using the isolated substorm list (Ohtani & Gjerloev, 2020, https://doi.org/10.1029/2020ja027902) clearly shows signatures of energetic proton parallel pressure anisotropy immediately before substorm onset, potentially supportive of the Oberhagemann and Mann theory.

Abstract

Low-cost instrumentation combined with volunteering and citizen science educational initiatives allowed the deployment of L-band scintillation monitors to remote sense areas that are geomagnetically conjugated and located at low-to-mid latitudes in the American sector (Quebradillas in Puerto Rico and Santa Maria in Brazil). On 10 and 11 October, 2023, both monitors detected severe scintillations, some reaching dip latitudes beyond 26°N. The observations show conjugacy in the spatio-temporal evolution of the scintillation-causing irregularities. With the aid of collocated all-sky airglow imager observations, it was shown that the observed scintillation event was caused by extreme equatorial plasma bubbles (EPBs) reaching geomagnetic apex altitudes exceeding 2,200 km. The observations suggest that geomagnetic conjugate large-scale structures produced conditions for the development of intermediate scale (few 100 s of meters) in both hemispheres, leading to scintillation at conjugate locations. Finally, unlike previous reports, it is shown that the extreme EPBs-driven scintillation reported here developed under geomagnetically quiet conditions.

Abstract

The distribution and magnitude of forces driving lithospheric deformation in the India-Eurasia collision zone have been debated over many decades. Here we test a two-dimensional (2-D) Thin Viscous Shell approach that has been adapted to explicitly account for displacement on major faults and investigate the impact of lateral variations in depth-averaged lithospheric strength. We present a suite of dynamic models to explain the key features from new high-resolution Sentinel-1 Interferometric Synthetic Aperture Radar as well as Global Navigation Satellite System velocities. Comparisons between calculated and geodetically observed velocity and strain rate fields indicate: (a) internal buoyancy forces from Gravitational Potential Energy acting on a relatively weak region of highest topography (>2,000 m) contribute to dilatation of the high plateau and contraction on the margins; (b) a weak central Tibetan Plateau (∼1021 Pa s compared to far-field depth-averaged effective viscosity of at least 1022–1023 Pa s) is required to explain the observed long-wavelength eastward velocity variation; (c) localized displacement on fault systems enables strain concentration and clockwise rotation around the Eastern Himalayan Syntaxis. We discuss the tectonic implications for rheology of the lithosphere, distribution of geodetic strain, and partitioning of active faulting and seismicity.

Abstract

In this contribution we introduce the dual mixed-integer least-squares problem and study it in relation to its primal counterpart. The dual differs from the primal formulation in the order in which the integer ambiguity vector \(a \in {\mathbb {Z}}^{n}\) and baseline vector \(b \in {\mathbb {R}}^{p}\) are estimated. As not the ambiguities, but rather the entries of b are usually the parameters of interest, the attractiveness of the dual formulation stems from its direct computation of b. It is shown that this potential advantage relies on the ease with which an implicit integer least-squares problem of the dual can be solved. For the convoluted cases, we introduce two methods of simplifying approximations. To be able to describe their quality, we provide a complete distributional analysis of their estimators, thus allowing users to judge whether or not the approximations are acceptable for their application. It is shown that this approach implicitly introduces a new class of admissible integer estimators of which we also determine the pull-in regions. As the dual function is shown to lack convexity, special care is required to be able to compute its global minimizer \({\check{b}}\) . Our proposed method, which has finite termination with a guaranteed \(\epsilon \) -tolerance, is constructed from combining the branch-and-bound principle, with a special convex-relaxation of the dual, to which the projected-gradient-descent method is applied to obtain the required bounds. Each of the method’s three constituents are described, whereby special emphasis is given to the construction of the required continuously differentiable, convex lower bounding function of the dual.

Nature Geoscience, Published online: 24 June 2024; doi:10.1038/s41561-024-01472-8

An absence of sapropels in eastern Mediterranean sediments suggests an expansion of vegetation over a relatively humid North African landscape preceding the mid-Pliocene glaciation, potentially facilitating early human migration.

С.М. Стишов

Обсуждаются термодинамические свойства классических и квантовых больцмановских простых систем. Указывается, что стандартные формулы классического идеального газа на самом деле описывают квантовый больцмановский газ. Анализируется теплоёмкость классических и квантовых больцмановских систем. Рассматривается плавление классичеcких систем и больцмановских квантовых твёрдых сфер.