Polar Regions Research Articles

Public engagement in polar science: perspectives from tourists and scientists on the SEES-2022 expedition to Svalbard

ABSTRACT Public engagement with polar regions is crucial for raising awareness and garnering support for these vulnerable environments. Cruise tourism offers unique opportunities for engagement through immersive experiences of polar landscapes and wildlife, lectures, and citizen science activities, deepening understanding of polar ecosystems and human impacts. This paper presents the case of the SEES-2022 Netherlands Scientific Expedition Edgeøya Svalbard, a distinctive public engagement activity. Fifty-two scientists joined an Arctic Academy tourism cruise alongside 35 tourists, seven policy representatives, one artist, and seven journalists. The Arctic Academy emphasised active tourist involvement in scientific projects to enhance outreach and support for the Arctic’s climate challenges. Extensive media coverage throughout SEES-2022 shared these experiences with the wider public. The study explores how integrating tourism and science may strengthen public engagement and awareness by examining perspectives from both tourists and scientists. Findings show that, while tourism-science combinations involve trade-offs, they enhance science outreach. Immersive tourism-science experiences can promote deeper understanding of human impacts on polar regions among tourists and encourage dialogue on sustainable tourism. Although SEES-2022 is a unique case, its findings can inspire broader discussions on developing effective public engagement in polar regions. Drawing on insights from the case study, six recommendations are proposed for future tourism-science blends that foster meaningful public engagement, raise awareness, and enhance knowledge of polar ecosystems.

A gradient-boosted tree framework to model the ice thickness of the world's glaciers (IceBoost v1.1)

Abstract. Knowledge of glacier ice volumes is crucial for constraining future sea level potential, evaluating freshwater resources, and assessing impacts on societies, from regional to global. Motivated by the disparity in existing ice volume estimates, we present IceBoost, a global machine learning framework trained to predict ice thickness at arbitrary coordinates, thereby enabling the generation of spatially distributed thickness maps for individual glaciers. IceBoost is an ensemble of two gradient-boosted trees trained with 3.7 million globally available ice thickness measurements and an array of 39 numerical features. The model error is similar to those of existing models outside polar regions and is up to 30 %–40 % lower at high latitudes. Providing supervision by exposing the model to available glacier thickness measurements reduces the error by a factor of up to 2 to 3. A feature-ranking analysis reveals that geodetic data are the most informative variables, while ice velocity can improve the model performance by 6 % at high latitudes. A major feature of IceBoost is a capability to generalize outside the training domain, i.e. producing meaningful ice thickness maps in all regions of the world, including on the ice sheet peripheries.

Wintertime Trends in Directional Variability and Intensity of Westerly Air Flow in the Polar Jet Region

ABSTRACTIn the current scientific debate, considerable attention is given to identifying changes in the midlatitude upper‐tropospheric wind field that may be associated with Arctic warming. The air flow patterns, such as waviness, blocking and splitting, are among the most frequently studied. In this paper, we analyse changes in both the geometry and intensity of the westerly flow within the polar front jet (PFJ) stream sector. For this purpose, we introduce zonally defined circular statistics. Significant changes in the wind field were detected in the northern flank of the PFJ, close to the Arctic border. In this region, the directional variability of the wind vector calculated in the latitudinal domain increases over a multi‐year period, and the latitudinal series of wind vectors becomes increasingly deflected from the purely zonal West‐to‐East direction. The most significant deflection trend is observed for northerly winds. Wind rose diagrams constructed for the Arctic boundary latitude band complement the picture of these changes, indicating an increased frequency of wind vectors from the N‐E‐S semicircle during the period 2001–2022 relative to 1980–2000. Alongside changes in flow geometry, the entire sector also experiences PFJ dissipation. The sign of the trends reverses in the southern flank of the PFJ; however, wind directional changes do not reach statistical significance. Within this flank, the PFJ and the subtropical jet (STJ) occur more frequently, which is accompanied by the stabilisation of westerly flow directions. These results support the hypothesis that, in the era of Arctic Amplification, non‐zonal or irregular flow patterns are intensifying in the upper‐tropospheric polar latitudes.

Vertical shear instabilities in rotating stellar radiation zones: effects of the full Coriolis acceleration and thermal diffusion

Abstract Rotation deeply impacts the structure and the evolution of stars. To build coherent 1D or multi-D stellar structure and evolution models, we must systematically evaluate the turbulent transport of momentum and matter induced by hydrodynamical instabilities of radial and latitudinal differential rotation in stably stratified thermally diffusive stellar radiation zones. In this work, we investigate vertical (radial) shear instabilities in these regions. The full Coriolis acceleration with the complete rotation vector at a general latitude is taken into account. We formulate the problem by considering a canonical shear flow with a hyperbolic-tangent profile. We perform linear stability analysis on this base flow using both numerical and asymptotic Wentzel-Kramers-Brillouin-Jeffreys (WKBJ) methods. Two types of instabilities are identified and explored: inflectional instability, which occurs in the presence of an inflection point in shear flow, and inertial instability due to an imbalance between the centrifugal acceleration and pressure gradient. Both instabilities are promoted as thermal diffusion becomes stronger or stratification becomes weaker. Effects of the full Coriolis acceleration are found to be more complex in our parametric investigations in wide ranges of colatitudes and rotation-to-shear and rotation-to-stratification ratios. Also, new prescriptions for the vertical eddy viscosity are derived to model the turbulent transport triggered by each instability. We foresee that the inflectional instability will be responsible for turbulent transport in the equatorial region of strongly-stratified radiative zones in slowly rotating stars while the inertial instability triggers turbulence in the polar regions of weakly-stratified radiative zones in fast-rotating stars.

Dynamic Simulation and Characteristic Analysis on Freezing Process in Ballast Tanks of Polar LNG Carriers

The ballast tank is a critical system for LNG carriers, ensuring structural safety and stability during navigation. When LNG carriers navigate in polar regions, the ballast tank is prone to freezing, which will reduce the efficiency of ballast water circulation. Furthermore, the freezing process generates frost heaving forces that may damage the walls of the ballast tank, shorten the structure’s service life, and disrupt the ship’s normal operations. Therefore, analyzing the freezing process of ballast tanks is essential. This paper focuses on the ballast tank of a polar LNG carrier as the research subject. It assumes that the ballast water is fresh water with unchanging physical properties and takes into account the environmental conditions in polar regions. A numerical simulation model of the freezing process within the ballast tank is established. This study investigates the influence of various environmental parameters on the freezing process and determines the evolution of ice shape in relation to temperature field changes under different environmental conditions. The results indicate that as the ambient temperature decreases, the rate of temperature reduction at the ballast water level accelerates, resulting in a thicker ice layer formed by freezing. Additionally, as the seawater temperature decreases, the rate of temperature decline in the ballast water at the bulkhead is significantly accelerated, leading to an increased rate of ice shape evolution. Furthermore, a reduction in the height of the ballast water level enhances the heat transfer rate of the ballast water, which markedly increases the degree of freezing in the ballast water.

Polarization signals of luminous supernovae by jet-driven bipolar explosions

Abstract Superluminous supernovae (SLSNe) and luminous supernovae (LSNe) exhibit extreme luminosities that cannot be explained by traditional explosion models, often requiring additional energy sources such as central engines or circumstellar interaction. In the central-engine scenario, jets inject energy into the polar ejecta, modifying its evolution and shaping the explosion geometry. This study investigates the polarization signatures of jet-driven bipolar explosions in SLSNe/LSNe, where the asymmetric ejecta structure and differential photospheric evolution imprint distinct observational features. We develop a two-component ejecta model, consisting of fast-expanding polar ejecta (powered by jets) and slower equatorial ejecta. We find that polarization exhibits complex temporal evolution, where the ejecta geometry and flux asymmetry between the two regions jointly produce a double-peaked feature. In addition, the line opacity in the polar region further enhances the wavelength dependence of the polarisation. Spectropolarimetric observations, particularly during early phases, can constrain the geometry and energy sources of SLSNe/LSNe, advancing our understanding of their explosion mechanisms.

Glacier Recession and Climate Change in Chitral, Eastern Hindu Kush Mountains of Pakistan, Between 1992 and 2022

Mountain regions are particularly sensitive and vulnerable to the impacts of climate change. Over the past three decades, mountain temperatures have risen significantly faster than those in lowland areas. The Hindu Kush–Karakoram–Himalaya region, often referred to as the “water tower of Asia”, is the largest freshwater source outside the polar regions. However, it is currently undergoing cryospheric degradation as a result of climatic change. In this study, the Normalized Difference Glacier Index (NDGI) was calculated using Landsat and Sentinel satellite images. The results revealed that glaciers in Chitral, located in the Eastern Hindu Kush Mountains of Pakistan, lost 816 km2 (31%) of their total area between 1992 and 2022. On average, 27 km2 of glacier area was lost annually, with recession accelerating between 1997 and 2002 and again after 2007. Satellite analyses also indicated a significant increase in both maximum (+7.3 °C) and minimum (+3.6 °C) land surface temperatures between 1992 and 2022. Climate data analyses using the Mann–Kendall test, Theil–Sen Slope method, and the Autoregressive Integrated Moving Average (ARIMA) model showed a clear increase in air temperatures from 1967 to 2022, particularly during the summer months (June, July, and August). This warming trend is expected to continue until at least 2042. Over the same period, annual precipitation decreased, primarily due to reduced snowfall in winter. However, rainfall may have slightly increased during the summer months, further accelerating glacial melting. Additionally, the snowmelt season began consistently earlier. While initial glacier melting may temporarily boost water resources, it also poses risks to communities and economies, particularly through more frequent and larger floods. Over time, the remaining smaller glaciers will contribute only a fraction of the former runoff, leading to potential water stress. As such, monitoring glaciers, climate change, and runoff patterns is critical for sustainable water management and strengthening resilience in the region.

On the Impact of Neutrinos on the Launching of Relativistic Jets from “Magnetars” Produced in Neutron Star Mergers

Abstract A significant interest has emerged recently in assessing whether collimated and ultrarelativistic outflows can be produced by a long-lived remnant from a binary neutron star (BNS) merger, with different approaches leading to different outcomes. To clarify some of the aspect of this process, we report the results of long-term (i.e., ∼110 ms) state-of-the-art general relativistic magnetohydrodynamics simulations of the inspiral and merger of a BNS system of magnetized stars. We find that after ∼50 ms from the merger an α–Ω dynamo driven by the magnetorotational instability sets in in the densest regions of the disk and leads to the breakout of the magnetic field lines from the accretion disk around the remnant. The breakout is responsible for generating a collimated, magnetically driven outflow with only mildly relativistic velocities and for a violent eruption of electromagnetic energy. We provide evidence that this outflow is partly collimated via a Blandford–Payne mechanism. Finally, by including or not the radiative transport via neutrinos, we determine the role they play in the launching of the collimated wind. In this way, we conclude that the mechanism of magnetic field breakout we observe is robust and takes place even without neutrinos. Contrary to previous expectations, the inclusion of neutrino absorption and emission leads to a smaller baryon pollution in polar regions and hence accelerates the occurrence of the breakout, yielding a larger electromagnetic luminosity. Given the mildly relativistic nature of these disk-driven breakout outflows, it is difficult to consider them responsible for the jet phenomenology observed in short gamma-ray bursts.

Gravitational waves from magnetars

We study the emission of gravitational waves produced by the magnetosphere of magnetars. We argue that several features in the spectrum could facilitate the identification of that source. In addition, in cases of extremely large magnetic fields we demonstrate that this emission can contribute to the deviation of the braking index from 3, which is the standard prediction of the magnetic dipole radiation and aligned rotator mechanisms. A similar picture arises if one focuses on the second braking index. Moreover, the braking index depends in a specific way on both the rotational frequency and the strength of the magnetic field which could facilitate the identification of this mechanism with respect to others. We also show that gravitational waves can be produced by polar gap regions due to their rapid charge-discharge process that takes place in timescales from nanosec to microsec. This can provide an alternative way to probe magnetars and test the polar gap model.

Generalized entropy of photons in AdS

This work analyzes the quantum corrections to holographic entanglement entropy at first subleading order in GN due to photon excited states in AdS. We compute the vacuum-subtracted von Neumann entropy of a U(1) current excited state for a polar cap region on the cylinder in any large-N, strongly-coupled CFTd holographically dual to weakly-coupled Einstein gravity for any dimension d > 2. We then quantize a Maxwell field in AdSd+1 dual to the U(1) current and consider a photon excited state whose vacuum-subtracted generalized entropy for the entanglement wedge is calculated. In order to factorise the Maxwell Hilbert space in AdS, we construct an extended Hilbert space and the corresponding electromagnetic edge modes. We find exact agreement between the CFT entanglement entropy and AdS generalized entropy without the inclusion of entropy of the edge modes. Finally, we show via explicit calculation that the contribution to the vacuum-subtracted von Neumann entropy from electromagnetic edge modes indeed vanishes, which is crucial for consistency with known holographic entropy formulas.

Evolution of curing residual stresses for filament‐wound egg‐shaped pressure‐resistant shells considering viscoelastic properties

AbstractThe filament‐wound egg‐shaped structure offers significant performance improvements and structural advantages for deep‐sea submersibles, including enhanced pressure resistance, optimized space utilization, and improved hydrodynamic performance. However, the residual stresses generated by the curing process are an unavoidable key issue in filament winding. This study aims to investigate the thermal curing residual stresses and its resultant distortions on filament‐wound egg‐shaped pressure‐resistant shells under different structural parameters. First, the wound trajectory is determined based on the principles of differential geometry and the fourth‐order Runge–Kutta method combined with the egg‐shaped profile equation. Then, a thermo‐chemical–mechanical multi‐field coupling analysis is conducted using the Kamal autocatalytic curing kinetics model and the generalized Maxwell viscoelastic constitutive model. The curing mechanism of the egg‐shaped filament‐wound pressure structure is revealed. Finally, a comprehensive analysis is conducted on the influence of structural design parameters including shape index (SI), slip coefficient, layer thickness, and liner thickness on residual stress and deformation. The results show that the residual stress in the fiber direction increases sharply with temperature during the curing process, reaching its peak during the secondary curing stage, and gradually relaxes during the cooling phase. The stress in the polar region is complex, while it is more uniform in the non‐polar regions. Parametric analysis indicates that the residual stress and displacement of the metal liner for shape index 0.8 increase significantly by 148.02% and 125.44% compared to shape index 0.4.Highlights Consider the viscoelastic behavior of the resin in curing predictions. Outside the polar hole, the outermost wound layer shows compressive stress. In non‐polar pores, stresses in filament‐wound layers fall outward. Adjusting the slip coefficient reduces curing deformation and residual stress. Shape index, ply, and liner thickness significantly impact residual stress.

Sea Breeze-Driven Variations in Planetary Boundary Layer Height over Barrow: Insights from Meteorological and Lidar Observations

The planetary boundary layer height (PBLH) in coastal Arctic regions is influenced by sea breeze circulation. However, the specific mechanisms through which sea breeze affects PBLH evolution remain insufficiently explored. This study uses meteorological data, micro-pulse lidar (MPL) data, and sounding profiles from 2014 to 2021 to investigate the annual and polar day PBLH evolution driven by sea breezes in the Barrow region of Alaska, as well as the specific mechanisms. The results show that sea breeze events significantly suppress PBLH, especially during the polar day, when prolonged solar radiation intensifies the thermal contrast between land and ocean. The cold, moist sea breeze stabilizes the atmospheric conditions, reducing net radiation and sensible heat flux. All these factors inhibit turbulent mixing and PBLH development. Lidar and sounding analyses further reveal that PBLH is lower during sea breeze events compared to non-sea-breeze conditions, with the peak of its probability density distribution occurring at a lower PBLH range. The variable importance in projection (VIP) analysis identifies relative humidity (VIP = 1.95) and temperature (VIP = 1.1) as the primary factors controlling PBLH, highlighting the influence of atmospheric stability in regulating PBLH. These findings emphasize the crucial role of sea breeze in modulating PBL dynamics in the Arctic, with significant implications for improving climate models and studies on pollutant dispersion in polar regions.

Polar ectotherms more vulnerable to warming than expected.

Polar ectotherms more vulnerable to warming than expected.

Electric forces can enhance the emission of microplastics into air.

Electric forces can enhance the emission of microplastics into air.

Biological and terrestrial influences on dissolved organic matter in Antarctic surface waters: Insights from mass spectrometry and metagenomic analysis.

Biological and terrestrial influences on dissolved organic matter in Antarctic surface waters: Insights from mass spectrometry and metagenomic analysis.

Combined impact of pesticides on mono- and bilayer lipid membranes.

Combined impact of pesticides on mono- and bilayer lipid membranes.

Measurement of space charge density distributions and dielectric resonance enhancement of beam deflection properties of KTN crystal

Measurement of space charge density distributions and dielectric resonance enhancement of beam deflection properties of KTN crystal

A Model Based Study of the Emergence of North Atlantic Deep Water During the Cenozoic: A Tale of Geological and Climatic Forcings

AbstractThe North Atlantic Deep Water (NADW) is a key component of modern climate systems, redistributing heat from equatorial to polar regions and contributing to the Atlantic Meridional Overturning Circulation. However, the timing of its emergence and the mechanisms driving its formation remain uncertain. This study explores ocean circulation patterns during the middle Eocene (48–38 Ma) and early Miocene (23–16 Ma) using simulations with the IPSL‐CM5A2 climate model. In the middle Eocene simulations, reduced surface salinity in the North Atlantic prevents NADW formation, regardless of atmospheric levels or the presence of an Antarctic ice sheet. Conversely, early Miocene simulations suggest that paleogeographic shifts promote higher Atlantic salinity, enabling NADW formation. Specifically, the closure of the Polish Strait and the narrowing of the Central American Seaway enhance salt retention in the Atlantic and increase salt transport from subtropical to subpolar regions. Additionally, changes in African monsoonal precipitation—characterized by a reduction and eastward shift across Central Africa—reduce freshwater influx into the Atlantic between the middle Eocene and early Miocene. These combined factors weaken North Atlantic stratification, facilitating NADW development during the early Miocene. This research provides a timeline for NADW initiation and insights into the processes driving its formation.

Thermospheric Orthohelium, He23S $\mathrm{H}\mathrm{e}\left({\mathrm{2}}^{\mathrm{3}}\mathrm{S}\right)$, Variations Associated With a Moderate Storm in February 2023: The NIRAS‐2 Observations at the Kjell Henriksen Observatory (78.1°N, 16.0°E), Svalbard

AbstractThis study presents the time variability of metastable orthohelium, , in the polar region associated with a geomagnetic storm. A data set consisting of continuous observations of airglow brightness at 1,083 nm for 17 nights was obtained from a short‐wavelength infrared imaging spectrograph (NIRAS‐2) at the Kjell Henriksen Observatory, Svalbard (78.1°N, 16.0°E). The observed airglow brightness clearly displayed responses to the geomagnetic storm on different time scales. It began to decrease sharply within an hour of sudden commencement of the storm, and it gradually decreased over the next few days before recovering slowly. This behavior in brightness agreed to helium density variations at a 500‐km altitude calculated by MSIS 2.1. The depletion of was mainly caused by Penning ionization due to upwelling from the lower atmosphere; this was consistent with the decreased O/ ratio in the MSIS 2.1 calculation and TIMED/GUVI measurements, and electron density depletion in the F region observed by the EISCAT Svalbard Radar (ESR). Additionally, sudden increases in airglow brightness were clearly associated with intermittent electron precipitations observed by the ESR. Therefore, direct impacts by precipitating electrons injected from space into the polar upper atmosphere can play significant roles in production of . The NIRAS‐2 measurements demonstrated that from the upper thermosphere to the exosphere changed drastically as a result if forcing both from the lower atmosphere and from space. measurements will improve our understanding of the thermosphere‐ionosphere coupling system and extend the coverage of space weather forecasting up to the exobase.

Modeling the Impacts of Antarctic Sea Ice Decline: Responses of Atmospheric Dynamics

AbstractRapidly changing climate in polar regions not only impacts their local environments but also influences weather patterns in tropical and mid‐latitude regions. A key indicator of these changes is the accelerated decline of sea ice in polar areas. In this study, we investigated the atmospheric impacts of Antarctic sea ice reduction in response to intensified ocean surface winds. We employed the Polar‐WRF model, driven by ERA5 initial and boundary conditions between 2005 and 2011. The sea ice concentration (SIC) and sea surface temperature (SST) conditions were derived from two realistic regional Southern Ocean MITgcm simulations, consisting of a control and a wind sensitivity experiment. In the latter, the zonal wind stress over the Southern Ocean is increased by a factor of 1.5, leading to a significant decrease in SIC and an increase in SST. Our Polar‐WRF simulations indicate that the winter and spring seasons are marked by significant meteorological changes, including a notable increase in surface air temperature (over 2.4°C) and sea level pressure (over 2 hPa). These atmospheric changes are particularly large in the Bellingshausen Sea, adjacent to the Antarctic Peninsula and the Western Pacific Ocean. The intensified advection of warm‐moist air may further contribute to sea ice decline, with potential implications for increased melting of ice shelves in the Weddell and Ross Seas. The simulations illustrate that variations in wind stress could provide insights into the atmospheric‐sea ice dynamics driving recent record lows in Antarctic sea ice, underscoring the importance of such modeling for understanding and predicting changes.