The influence of topography on rotating fluids may exceed conventional expectations. Here, we numerically examine viscous incompressible flows induced by sidewall topography, confined within a modified cylinder that rotates rapidly about its central vertical axis and precesses about another axis. To investigate specific flow patterns and boundary-interior correspondences, the cylindrical sidewall is modified by adding a vertical fin-type barrier extending all the way from the bottom to the top. The fully nonlinear Navier−Stokes equations with precessional forcing are solved in this modified cylindrical geometry, using a mixed finite element method. Numerical results show that the introduction of sidewall topography significantly alters the precessionally driven flow, particularly at high precession rates. While the primary dynamics associated with inertial wave propagation persist, rich vortical structures and turbulence emerge. Interestingly, the barrier does not invariably suppress the kinetic energy density; when its height approaches the cylinder radius under strong precession, the kinetic energy density even exceeds that of the cylinder case without a barrier. Such an anomalous enhancement of kinetic energy may offer new insights into how precession-driven flows over topography could contribute to sustaining long-lived planetary magnetic fields, including that of the early Moon.

Atmospheric gravity waves (AGWs) observed by the All-Sky Airglow Imager (ASAI) require accurate identification for the study of atmospheric coupling mechanisms and space weather prediction. However, the traditional manual screening methods and existing machine learning approaches do not meet the demands of practical station monitoring, which has significantly impeded climatological statistical research based on AGWs. Therefore, a real-time detection framework for ground-based airglow gravity waves that integrates transfer learning with adaptive image preprocessing has been proposed. By employing wavelength-adaptive median filtering and multiscale fusion, the framework effectively suppresses stellar noise while preserving weak gravity wave features. The model utilizes an EfficientNet-B3 (convolutional neural network) backbone enhanced with a deformable convolutional layer, trained via a two-stage strategy: A frozen phase prevents overfitting by locking the lower level feature extractor, and a fine-tuning phase optimizes the deformable convolution through cosine annealing and layered optimization. This approach improves both feature transfer efficiency and gravity wave detection sensitivity. The resulting lightweight model achieves 91.2% accuracy with millisecond-level inference speed (23 ms per frame).

A rocket launch can induce large-scale atmospheric disturbances, which have mainly been investigated in previous studies by using measurements of total electron content. In this study, we report the perturbation in very low frequency (VLF) transmitter signals triggered by a rocket launch event, which, unlike total electron content measurements, is directly related to the D-region ionosphere. The perturbation in VLF measurements typically occurred ~9 min after liftoff, resulting in an amplitude change of up to 2.82 dB, and it had a common period of ~3.5–7 min. Moreover, the perturbation consisted of two isolated pulses, a feature notably different from previous measurements. Given the close correlation between the rocket launch and the VLF measurements, as well as the similarity between different propagation paths, these perturbations were likely caused by shock acoustic waves generated during the rocket launch because the periods were similar.

To understand energy transfer during sudden stratospheric warming (SSW) events in the middle atmosphere, the 2023 SSW is studied by using the analysis tools of the multiscale window transform (MWT) and MWT-based localized energetics analysis and theory of canonical transfer (MS-ECT). The energy transfer in the mesosphere is diagnosed and compared with that in the stratosphere. The energy fields are first reconstructed onto three scale windows: a large-scale window, an SSW-scale window, and a synoptic-scale window. Results showed that the work done by pressure (pressure flux) plays a critical role in coupling the mesosphere and stratosphere during SSW events. The cross-scale energy transfer (canonical transfer) of available potential energy is always directed from the large-scale to the SSW-scale window, indicating the central role of baroclinic instability in both the stratosphere and mesosphere. Comparative analysis with the 2012–2013 SSW event revealed the consistent presence of baroclinic instability across both events. However, the 2023 event exhibited significantly stronger energy transfer magnitudes in the mesosphere. These results highlight the consistent role of baroclinic instability and pressure flux in mediating cross-scale energy transfer during SSWs, providing a clearer understanding of stratosphere–mesosphere coupling.

Edge detection represents a critical task in potential field data interpretation and is extensively utilized for detecting faults, contacts, and other linear geological structures. However, conventional methods are constrained by several limitations, including inadequate balancing of signals with varying amplitude intensities, dispersed detection results, and insufficient suppression of spurious signals. To overcome these challenges, we propose an improved edge detection method, designated as the hyperbolic tangent (TANH) function with Gaussian envelope constraints on the total gradient modulus tilt angle (THASTG). The THASTG method is formally defined as a tilt angle approach based on the total gradient modulus, incorporating dual constraints through a Gaussian envelope and a TANH function. We initially conducted comparative analyses between the THASTG and established methods by using complex models simulating three distinct geological scenarios, thereby validating the feasibility of the methodology. Subsequent application to real gravity data from the South China Sea region demonstrated that compared with conventional techniques, THASTG yields enhanced structural detail, improved boundary resolution, and superior noise suppression. This method effectively suppresses noise interference and successfully avoids the introduction of spurious boundaries while maintaining consistency with previously documented major tectonic features. This study provides high-resolution structural constraints for the South China Sea region, delineates the offshore extension of the Red River Fault system, and accurately maps the continent–ocean boundary configuration. Our results demonstrate that the proposed methodology provides an effective tool for precise structural characterization and in-depth analysis of geodynamic evolution processes.

The distribution and transport of carbon dioxide (CO₂) in the middle and upper atmosphere are closely linked to atmospheric dynamical processes, but the influence of planetary waves on CO₂ transport remains unclear. This study aims to investigate the impact of quasi-2-day waves (Q2DWs) on CO₂ transport in the stratosphere–mesosphere during the sudden stratospheric warming (SSW) period. On the basis of data assimilation (DA) using the Whole Atmosphere Community Climate Model (WACCM) + Next-generation Ensemble Data Assimilation System (NEDAS) from December 2018 to February 2019, we used the transformed Eulerian mean framework to conduct a diagnostic analysis on Q2DW propagation and amplification. Additionally, we identified unstable regions in the stratosphere between 60°N and 80°N. This configuration facilitates the amplification of Q2DWs through enhanced baroclinic and barotropic instabilities. The results demonstrate that the dynamic features exhibit distinct propagation and amplification characteristics. We also found distinct Q2DWs in CO₂ at the middle latitudes of the southern hemisphere, which were mainly induced by the Q2DWs in temperature. Further analysis showed that the anomalous vertical motion during the SSW period could lead to the enhancement of CO₂ vertical gradients, which also contributed to the strengthening of Q2DWs in CO₂.

The formation of spicules on the solar surface is poorly understood. In the present investigation, we propose a mechanism that provides an explanation for this phenomenon. The squeeze of the enhanced downflow region in the intergranular lanes by oscillation results in an initial narrow, high-speed upward flow with a velocity on the order of several kilometers per second and a width on the order of 10 km. The underlying physics principle is the same as in the design of an anti-tank weapon, called a “shaped charge”. The life of a spicule is divided into two stages. The first stage is mechanical driving by the pressure gradient at its base; the second stage is electromagnetic driving. Dynamo action in the early lifetime of a spicule plays an important role in the transfer of mechanical energy to magnetic energy. The subsequent Fermi acceleration is responsible for the energy transfer from magnetic energy to thermal energy and kinetic energy. Depending on the strength of the ambient magnetic field, the formation of type I spicules (strong case) and type II spicules (weak case) can be naturally explained in this frame setting, which is one of the merits of our proposed mechanism. The variation in temperature along the height is consistent with prior observation-based models.

Electron dynamics plays a crucial role in the evolution of the Martian ionosphere. However, the adiabatic process, a classical mechanism for modulating electron energy and pitch-angle distributions, has not been reported in this environment. Utilizing data from the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, we present evidence of a decrease in electron perpendicular energy predominantly driven by betatron cooling in the Martian ionosphere. The phenomenon was identified within closed magnetic field lines at the edge of the crustal magnetic fields, a region characterized by a convoluted magnetic field topology comprising both closed and open lines. The observed cooling of 10–150 eV electrons with a power-law distribution, enhancing the cigar distribution, was quantitatively reproduced by an adiabatic model. Our study may promote the understanding of electron dynamics in the Martian ionosphere.

As a planet lacking a global magnetic field, Mars interacts directly with the solar wind, forming an induced magnetosphere that mediates energy transfer and atmospheric ion loss. The topology of this interaction and the resulting atmospheric ion escape are strongly influenced by the orientation of the interplanetary magnetic field (IMF). In this study, we utilize a hybrid model to investigate how variations in the IMF orientation shape ion current systems and atmospheric ion escape rates of O⁺, O₂⁺, CO₂⁺. We first perform simulations with a constant |B_sw|, where varying the IMF cone angle results in different strengths of the convective electric field (E_sw = V_sw × B_sw). Our results suggest that the spatial morphology of ion plumes undergoes a substantial evolution, forming a distinct cross-flow plume as the IMF rotates from perpendicular to parallel. These ion plumes exhibit a mass-dependent deflection, where heavier CO₂⁺ travel farther with larger gyroradii than lighter O⁺, acting as an asymmetric obstacle in the –Y_MSE hemisphere (where MSE is the Mars solar electric coordinate frame). In turn, the solar wind proton current develops pronounced asymmetries under a parallel IMF, becoming largely diffused in the −Y_MSE hemisphere because of the interaction with the additional plume obstacles. Consequently, the ion escape rates exhibit a nonmonotonic dependence on the IMF orientation, peaking under a parallel  IMF as escape shifts from a tail- to plume-dominated flow with substantial upstream enhancement. To decouple the effects of IMF geometry from those of the convective electric field, we further conduct a comparative simulation with constant  B_y  (hence constant |E_sw|), where the cone angle is varied by changing the B_x component while allowing |B_sw| to vary. With increasing B_x toward a parallel orientation, the total field magnitude grows, causing the Alfvén Mach number (M_A) to decrease from super-Alfvénic to trans-Alfvénic and ultimately to sub-Alfvénic values. Within the range from perpendicular to a 30° cone angle, where the system remains in the super-Alfvénic regime, ion escape is largely insensitive to the growing B_x component. This finding indicates that the magnetic barrier maintains its shielding efficiency under the super-Alfvénic regime.

Whistler-mode waves are ubiquitous in space environments and constitute a key mechanism for energy transfer and transformation. The near-1 Hz narrowband whistler-mode waves are commonly observed in lunar space. However, the generation mechanism of narrowband 1 Hz whistler-mode waves in the lunar environment, where no global magnetosphere or permanent bow shock exists, remains an open question. This study examines 1 Hz waves in the lunar environment by analyzing 12 years (2012–2023) of ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun) mission data (across an entire solar cycle). The spatial distribution, spectral characteristics, and polarization properties of these waves are investigated alongside their dependence on upstream solar wind parameters and lunar magnetic anomalies. The results reveal that 1 Hz waves are predominantly observed in the solar wind near the Moon, with clear dawn–dusk and north–south asymmetries. Wave amplitudes range from 0.03 to 1 nT, and approximately 90% of the events demonstrate no direct magnetic connectivity to the Moon. Importantly, wave amplitude shows a positive correlation with the solar wind dynamic pressure (P_dyn) and the total interplanetary magnetic field (B_total) and an inverse correlation with the Alfvén Mach number (M_A), underscoring the influence of upstream conditions on wave properties. Our findings reveal that the majority of waves occur on unconnected field lines, indicating a more complex generation and propagation scenario than previously assumed. Furthermore, wave properties are quantitatively shown to be strongly modulated by upstream solar wind conditions. These results provide critical statistical constraints for future studies of wave generation in the unique plasma environment of an unmagnetized body.