Search Results (849)

Ice and snow tourism (IST) is a significant global trend, offering Russia opportunities for tourism growth and seasonal diversification. This study investigates the potential of ice and snow art as a distinct subcategory of IST on Lake Baikal. Our research is based on an analysis of academic publications and official policy documents, field surveys conducted in winter 2025, and stakeholder consultations, with the “Olkhon Ice Fest” serving as a case study. The findings indicate a clear shift toward IST, with the number of winter tourists on Olkhon Island increasing by 70% between 2021 and 2024. The festival’s key features—its use of the natural ice landscape, a unique artistic technique, an explicit ecological focus, and strong entrepreneurial initiative—support the development of a conceptual model of IST on Lake Baikal grounded in ecotourism principles. Ensuring the long-term sustainable development of IST in the region requires improved governance, infrastructure, and transport systems, as well as support for green businesses and increased environmental awareness among tourists. This study contributes to the ongoing discourse on sustainable winter tourism by demonstrating the interconnections among environmental sustainability, socioeconomic benefits, and cultural innovation, thereby situating local IST practices within the broader framework of the United Nations Sustainable Development Goals (SDGs). Full article

Recent studies have shown that lidar observations from the Ice, Clouds, and Land Elevation Satellite-2 (ICESat-2) enable seasonal snow depth retrieval over land through two primary approaches. The snow-on–off method estimates snow depth by differencing surface elevations acquired during snow-covered and snow-free periods, while the pathlength method derives it from multiple-scattering photon distributions within the snowpack. In this study, we cross-validate ICESat-2-derived surface elevations and snow depths against in situ measurements from SnowEx field campaigns. ICESat-2 surface elevations agree closely with SnowEx data, which we consider closest to the truth, achieving centimeter-level accuracy (e.g., 1 cm) over flat, sparsely vegetated terrain, with larger biases in vegetated and steep areas. Snow depth estimates from both methods show comparable performance in the tundra area, with typical errors on the order of tens of centimeters; however, in vegetated or steep terrain, the pathlength method yields more reliable snow depth results, being less affected by slope and vegetation than the snow-on–off method. These findings show that ICESat-2 is a reliable tool for measuring snow depth from space. Full article

Freeze-thaw (F-T) cycles in seasonally frozen regions induce progressive volumetric strains leading to degradation of soils’ mechanical properties and performance of earthen infrastructure. Conventional chemical stabilization techniques often are not adaptive to cyclic thermal stresses and do not address the fundamental phase changes of porous media, underscoring the need for sustainable alternatives. This study explores the potential of extracellular polymeric substances (EPS) produced by the psychrophilic bacterium Polaromonas hydrogenivorans as a bio-mediated soil treatment to enhance freeze-thaw durability. Two EPS formulations were examined—EPS 1 (high ice-binding activity) and EPS 2 (low ice-binding activity)—to evaluate their effectiveness in improving volumetric stability and thawing strength of silty soil subjected to ten F-T cycles. Tests were conducted at four moisture contents (12%, 18%, 24%, and 30%) and three EPS concentrations (3, 10, and 20 g/L). Volumetric strain measurements quantified freezing expansion and thawing contraction, while unconfined compressive strength assessed post-thaw mechanical integrity. The untreated soils exhibited maximum net volumetric strains (γ_Net) of 5.62% and only marginal strength recovery after ten F-T cycles. In contrast, EPS 1 at 20 g/L mitigated volumetric changes across all moisture contents and increased compressive strength to 191.2 kPa. EPS 2 yielded moderate improvements, reducing γ_Net to 0.98% and enhancing strength to 183.9 kPa at 30% moisture. Lower EPS concentrations (3 and 10 g/L) partially mitigated volumetric strain, with performance strongly dependent on moisture content. These results demonstrate that psychrophilic EPS, particularly EPS 1, effectively suppresses ice formation within soil pores and preserves mechanical structure, offering a sustainable, high-performance solution for stabilizing frost-susceptible soils in cold-regions. Full article

Ice-and-snow tourism cities face pronounced seasonal fluctuations that place strong pressure on urban accommodation systems. Understanding the spatial distribution, accessibility, and service capacity of hotels is therefore critical for sustainable tourism management in cold-region cities. Taking Harbin, China, as a representative winter tourism destination, this study develops a GIS-based spatial analytical framework to examine the spatial organization and service performance of star-rated hotels. Using data from 553 three-star and above hotels, combined with questionnaire survey data (N = 224), we apply the Nearest Neighbor Index (NNI), Kernel Density Estimation (KDE), and raster-based cost-distance accessibility analysis to identify spatial clustering patterns, accessibility differentiation, and mismatches between hotel supply and peak seasonal demand. We find that available hotel rooms can only meet about 60% of peak-season demand, indicating a severe capacity deficit. The results reveal a clear core–periphery spatial structure of star-rated hotels, significant accessibility disparities among hotel categories, and a pronounced mismatch between accommodation capacity and tourism demand during peak winter seasons. Peripheral areas exhibit limited accessibility and insufficient service capacity, while central districts experience high concentration and pressure. These findings highlight the importance of integrating spatial equity and seasonal demand considerations into accommodation planning and infrastructure optimization, providing policy-relevant insights for sustainable tourism development in cold-region cities. Full article

Sea ice concentration (SIC) is crucial to the global climate. In this study, a new single-channel SIC retrieval algorithm utilizing spaceborne L-band brightness temperature (TB) measurements is developed based on a microwave radiative transfer model. Additionally, its four uncertainties are quantified and constrained: (1) variations in seawater reference TB under warm water conditions, (2) variations in sea ice reference TB under extremely low-temperature conditions, (3) the freeze–thaw dynamics of sea ice captured by Diurnal Amplitude Variation (DAV) signals, and (4) Land mask imperfections. It is found that DAV has the most pronounced effect: eliminating its influence reduces RMSE from 10.51% to 8.43%, increases R from 0.92 to 0.94, and minimizes Bias from -0.68 to 0.13. Suppressing all four uncertainties lowers RMSE to 7.42% (a 3% improvement). Furthermore, the algorithm exhibits robust agreement with the seasonal variability of SSM/I SIC, with R mostly exceeding 0.9, RMSE mostly below 10%, and Biases mostly within 5% throughout the year. Compared to ship-based and SAR SIC data, the new L-band algorithm’s Bias and RMSE are only 2% and 2% (ship-based)/2% and 1% (SAR) higher, respectively, than those of the SSM/I product. Future algorithms can integrate the DAV signal more effectively to better understand sea ice freeze–thaw processes and ice-atmosphere interactions. Full article

The formation and stability of river ice covers in regulated waterways are critical for uninterrupted hydro-electric operations. This study investigates the modelling of ice cover development in the Beauharnois Canal along the St. Lawrence River with the presence and absence of ice booms. Ice booms are deployed in this canal to promote the rapid formation of a stable ice cover during freezing events, minimizing disruptions to dam operations. Remote sensing data were used to assess the spatial extent and temporal evolution of an ice cover and to calibrate the river ice model RIVICE. The model was applied to simulate ice formation for the 2019–2020 ice season, first for the canal with a series of three ice booms and then rerun under a scenario without booms. Comparative analysis reveals that the presence of ice booms facilitates the development of a relatively thinner and more uniform ice cover. In contrast, the absence of booms leads to thicker ice accumulations and increased risk of ice jamming, which could impact water management and hydroelectric generation operations. Computational efficiencies of the RIVICE model were also sought. RIVICE was originally compiled with a Fortran 77 compiler, which restricted modern optimization techniques. Recompiling with NVFortran significantly improved performance through advanced instruction scheduling, cache management, and automatic loop analysis, even without explicit optimization flags. Enabling optimization further accelerated execution, albeit marginally, reducing redundant operations and memory traffic while preserving numerical integrity. Tests across varying ice cross-sectional spacings confirmed that NVFortran reduced runtimes by roughly an order of magnitude compared to the original model. A test GPU (Graphics Processing Unit) version was able to run the data interpolation routines on the GPU, but frequent data transfers between the CPU (Central Processing Unit) and GPU caused by shared memory blocks and fixed-size arrays made it slower than the original CPU version. Achieving efficient GPU execution would require substantial code restructuring to eliminate global states, adopt persistent data regions, and parallelize at higher level loops, or alternatively, rewriting in a GPU-friendly language to fully exploit modern architectures. Full article

Interannual climate changes and increasing atmospheric CO₂ (AtmCO₂) have significantly altered sea surface partial pressure of CO₂ (pCO₂) in the Beaufort Sea (BS). Yet, their decadal variability and underlying mechanisms remain inadequately understood. Using observational data and the Regional Arctic System Model (RASM), a decreasing trend transition of the BS summer surface pCO₂ was identified at around 2010–2012. Sensitivity cases reveal that the decadal trend transition in surface pCO₂ (early: 4.12 ± 0.80 μatm/yr, p < 0.05 and late: 1.23 ± 2.22 μatm/yr, p > 0.05) is driven by interannual climate changes. While the long-term increase in AtmCO₂ does not directly drive surface pCO₂ trend transition, it reduces its magnitude. The sensitivity experiment with no interannual AtmCO₂ changes from 1990 reveals that the statistically significant contributor of the decadal trend transition in surface pCO₂ is the concurrent transition in sea ice concentration (SIC, early: −0.0120 ± 0.0037/yr, p < 0.05 and late: 0.0101 ± 0.0063/yr, p > 0.05). The decadal trend transitions in the subsurface and deep layer pCO₂ are negligible compared to that in the sea surface pCO₂ due to the insignificant influence of interannual climate changes on subsurface and deep layer pCO₂. The surface pCO₂ decadal trend transition is significantly correlated with a trend transition of CO₂ sink. On seasonal timescales, the effects of SIC on the decadal trend transition of pCO₂ occur primarily within the duration of open-water (DOW), and align with the decadal trend transitions in the open-water start day, end day, and DOW. The magnitude of sea surface pCO₂ trend transition increases as the magnitude of the DOW trend transition increases. Full article

River and lake ice are sensitive indicators of climate change and important components of hydrological and ecological systems in cold regions. In this study, we develop a simple and transferable “surface water + land surface temperature (LST)” framework on Google Earth Engine to map potential winter ice area across China from 1990 to 2020. The framework enables consistent, large-scale, long-term monitoring without relying on complex remote sensing models or region-specific thresholds. Our results show that, despite a pronounced northwestward shift in the freezing-zone boundary, more than 400 km in the Northeast Plain and about 13 km per year along the eastern coast, the total ice-covered area increased by approximately 1.1% per year. At the same time, the average ice season became slightly shorter. This indicates asynchronous spatial and temporal responses of potential winter ice to warming. We identify a persistent “Northwest–Northeast dual-core” spatial pattern with strong positive spatial autocorrelation, characterized by increasing ice cover in Tibet, Qinghai, Xinjiang, Inner Mongolia, and Northeast China, and decreasing ice cover mainly in Beijing and Yunnan, where intense urbanization and low-latitude warming dominate. Random Forest modeling further shows that water area fraction, nighttime lights, built-up area, altitude, and water–heat indices are the main controls on potential winter ice. These findings highlight the combined influence of hydrological and thermal conditions and urbanization in reshaping potential winter ice patterns under climate change. Full article

Sea ice concentration (SIC) and thickness (SIT) are critical variables for polar research. In this study, the potential of Tianmu-1 GNSS-R observations for retrieving Arctic SIC and SIT is explored using machine learning algorithms. XGBoost demonstrated superior accuracy and efficiency in the comparison of the three methods. For SIC retrieval, 14 parameters from Tianmu-1 were employed directly, whereas SIT retrieval incorporated additional auxiliary parameters, including SIC, sea ice salinity (S), and temperature (T). Among the different GNSS systems, GLO achieved the lowest RMSE for SIC, at 7.750%, whereas GAL performed comparatively poorly, with an RMSE of 10.475%. In SIT retrieval, the GPS and BDS yielded the smallest RMSE values of 0.276 m and 0.278 m, respectively, while GLO resulted in a slightly higher RMSE of 0.309 m. Daily retrievals of both the SIC and SIT were conducted from 18 October 2023 to 12 April 2024, with consistently stable evaluation metrics throughout the freezing season. In high-concentration regions, the retrieved SIC and SIT closely matched the reference data, whereas larger errors occurred in marginal ice zones and coastal areas. This study reveals the potential of Tianmu-1 to complement existing satellite missions in Arctic sea ice monitoring during the freezing period. Full article

This investigation explored how seasonal variation affects the phytochemical composition and biological potential of Rosmarinus officinalis L., a widely used aromatic and medicinal plant. Aerial parts collected during spring, summer, autumn, and winter were extracted with ethanol and analyzed using LC-ESI-MS/MS, while total phenolic (TPC) and flavonoid (TFC) contents were determined spectrophotometrically. The extracts were evaluated for antioxidant, anti-inflammatory, enzyme inhibitory, analgesic, antimicrobial, cytotoxic, and photoprotective properties. Major constituents identified in all seasons included luteolin, kaempferol, rutin, and biochanin A. The autumn extract contained the highest phenolic (353.21 ± 4.05 µg GAE/mg) and flavonoid (190.11 ± 5.65 µg QE/mg) levels. Antioxidant assays revealed that the autumn extract had the strongest DPPH radical scavenging activity (IC₅₀ = 24.72 ± 0.16 µg/mL), while the spring extract exhibited the greatest reducing power (A_0.5 = 7.62 ± 0.30 µg/mL). The winter extract demonstrated superior anti-inflammatory activity (IC₅₀ = 28.60 ± 2.84 µg/mL), exceeding the reference drug diclofenac. Only the spring extract inhibited urease (IC₅₀ = 62.26 ± 0.58 µg/mL) and moderately inhibited α-amylase. All seasonal extracts showed notable photoprotective potential, with SPF values between 25.18 and 32.46, well above the recommended minimum. The spring extract also presented strong analgesic activity and no acute toxicity up to 2000 mg/kg. Antimicrobial effects were weak, limited to slight inhibition of Staphylococcus aureus, while moderate cytotoxicity was observed against MCF-7 and MDA-MB-231 breast cancer cells. Overall, seasonal variation significantly influenced the chemical profile and bioactivities of R. officinalis, with autumn and spring identified as the most suitable harvesting periods for pharmaceutical and cosmetic applications. Full article

The Loess Plateau is highly susceptible to landslides due to its fragile geological structure and frequent human activities, particularly old landslides with historical structural damage. The features of these landslides in remote sensing images become blurred over time, leading to huge challenges in detection. Considering that old landslides exhibit obvious shape characteristics, we propose ResU-SPMNet, a deep learning model that integrates shape characteristics into the baseline ResU-Net. The proposed model consists of three components: ResU-Net, shape prior module (SPM), and the atrous spatial pyramid pooling (ASPP) module, which jointly enhance segmentation performance from the perspectives of shape constraints and multi-scale feature representation. To validate the effectiveness of the proposed approach, old landslides in representative regions of the Loess Plateau were selected as the study targets. Results show that the proposed model outperforms ResU-Net, SegNet, MultiResUnet, and DeepLabv3+ in old landslide segmentation, achieving an F1-score of 0.6669 and an MCC of 0.6167. Moreover, generalization tests conducted in independent regions indicate that the model exhibits strong robustness across different seasons. The best performance is achieved in summer, whereas performance declines in winter due to adverse factors such as reduced illumination and snow or ice cover. Full article

This study investigated the site-specific ionic composition and wet deposition loads of rainwater collected from eight actively cultivated agricultural regions across South Korea, with the aim of quantifying spatial and seasonal variability and interpreting how regional agricultural characteristics and surrounding site conditions influence major ion concentrations and deposition patterns. Rainfall samples were obtained using automated samplers and analyzed via high-performance ion chromatography for major cations (Na⁺, $\mathrm{N}{\mathrm{H}}_4^{+}$, K⁺, Ca²⁺, Mg²⁺) and anions (Cl⁻, $\mathrm{N}{\mathrm{O}}_3^{-}$, $\mathrm{S}{\mathrm{O}}_4^{2-}$, $\mathrm{N}{\mathrm{O}}_2^{-}$). The results revealed significant seasonal fluctuations in ion loads, with $\mathrm{N}{\mathrm{H}}_4^{+}$ (peak 1.13 kg/ha) and K⁺ (peak 0.25 kg/ha) reaching their highest levels during summer due to increased fertilizer use and crop activity. Conversely, Cl⁻ peaked in winter (2.11 kg/ha in December), particularly in coastal regions, likely influenced by de-icing salts and sea-salt aerosols. Correlation analysis showed a strong positive association among $\mathrm{N}{\mathrm{H}}_4^{+}$, $\mathrm{N}{\mathrm{O}}_3^{-}$, and $\mathrm{S}{\mathrm{O}}_4^{2-}$ (r = 0.89 and r = 0.84, respectively), indicating shared atmospheric transformation pathways from agricultural emissions. Ternary diagram analysis further revealed regional distinctions: coastal regions such as Gimhae and Muan exhibited Na⁺ and Cl⁻ dominance, while inland areas like Danyang and Hongcheon showed higher proportions of Ca²⁺ and Mg²⁺, reflecting differences in aerosol sources, land use, and local meteorological conditions. These findings underscore the complex interactions between agricultural practices, atmospheric processes, and local geography in shaping rainwater chemistry. The study provides quantitative baseline data for evaluating non-point source pollution and developing region-specific nutrient and soil management strategies in agricultural ecosystems. Full article

The European seabass (Dicentrarchus labrax) is one of the most emblematic coastal fish species in the Northeast Atlantic, with high commercial value for fisheries and aquaculture, and importance for sport and recreational fishing. Despite its socio-economic importance, the Iberian divisions, Cantabrian Sea (8c) and the Atlantic Iberian waters (9a), defined by the International Council for the Exploration of the Sea (ICES), lack stock delimitation data. Moreover, this species is missing basic biological information, a seasonal reproductive fishing ban, and the annual landings in this region are more than double the levels recommended by ICES. To investigate the population structure of D. labrax in these areas, 140 adult individuals (36–51 cm of total length) were collected between January and March 2025 in three locations along the Atlantic coast of the Iberian Peninsula: Avilés (n = 47), Peniche (n = 48), and Lagos (n = 45). Fish from each location were analyzed for body geometric morphometrics (truss network) and otolith shape contour (Elliptical Fourier Descriptors). Data were evaluated using univariate and multivariate tests to assess spatial differences and reclassification success among locations. Results revealed regional differences using body morphometry and otolith shape analyses. The overall reclassification success was 68% for truss networking, 51% for otolith shape, and 65% when both methods were combined. Despite the observed differences, the absence of clear, isolated populations supports the ICES definition of a single, though not homogeneous, European seabass stock in the Atlantic Iberian coastal waters. Nevertheless, individuals from Avilés exhibited distinctive morphometric patterns and otolith shapes, suggesting possible adaptations to local selective pressures in slightly different environments. Further studies integrating genetic tools, otolith chemistry, parasitic fauna and telemetry analyses, as well as other fish samples from adjacent areas such as the Bay of Biscay, are recommended to achieve a more comprehensive understanding of the population structure and migration patterns of this key species in the Atlantic Iberian coastal waters. Full article

We investigated the impacts of a rapidly changing hydrometeorological regime on coastal erosion in the shallow, seasonally freezing Sea of Azov from 2000 to 2025. Our comparative approach integrated numerical modeling (SWAN), satellite remote sensing, and long-term field observations at two high-erosion sites: the Northern Site in Taganrog Bay and the Southern Site at the open sea boundary. The results demonstrate that coastal erosion is governed by complex, site-specific interactions rather than direct regional climatic trends. A major regime shift characterized by declining fast ice and increasing storm activity during the extended warm season has amplified coastal vulnerability, particularly after 2010. Despite high long-term average erosion rates at both sites, 1.1 to 1.6 m/year in the north and 1.5 to 1.8 m/year in the south, their annual erosion patterns were largely non-synchronous. The Northern Site is controlled by geological structure and surge phenomena, with peak rates reaching 8.5 m/year, while the Southern Site is governed by storm waves and extreme surges, enduring dynamic loads up to 10.0 tf/m². These results provide complex interaction nature of coastal processes and hydrometeorological components and its response to climate change in periodically freezing sea. These findings are vital for improving vulnerability models and underscore the necessity of site-specific hazard assessments for seasonally freezing coasts under a warming climate. Full article

Seasonal temperature reconstructions provide a critical approach for reconciling discrepancies between paleoclimate model simulations and proxy records. However, cold-season temperature variations remain poorly constrained due to the scarcity of robust cold-season temperature proxies. This study provides critical insights into lake ice-covered season temperature dynamics in Northeast China, a region where cold-season climate variability has remained poorly constrained in paleoclimate reconstructions. We collected total organic carbon sequences from seven closed lakes in Northeast China over the last 10,000 years to evaluate the lake ice cover duration as a proxy for lake ice-covered season temperature during the early–middle Holocene. Our results show that the lake ice cover duration decreased from ~8 ka BP, reaching a minimum at around 4 ka BP. This pattern is linked to ice-covered season temperature changes, with warmer ice-covered seasons leading to shorter ice cover durations and increased lake productivity, which were driven by orbital forcing (seasonal insolation changes) and greenhouse gas concentrations. Orbital forcing played a dominant role in winter warming between 8 and 4 ka BP, while greenhouse gas also contributed, but to a lesser extent. Full article