Search Results (144)

Stratospheric polar vortex (SPV) stretching events are typically of 1–2 weeks in duration when the SPV is elongated and locally extends anomalously south into lower latitudes. Such events are often associated with extreme cold over the Great Plains to southern and eastern states of the US. Here, we present an observational study of SPV stretching events. First, empirical orthogonal function (EOF) analyses were performed for daily geopotential height fields (in the Northern Hemisphere domain) at 500 and 100 hPa levels, respectively. The second modes (EOF2) are identified to be associated with SPV stretching events. Second, the evolution and morphology of geopotential height anomalies are described based on composite averaging over all individual events. The retrograding 500 hPa EOF2 positive circulation pattern may lead to SPV stretching (i.e., 100 hPa EOF2) and a cold wave in North America. Long-duration EOF2+ events (principal component amplitude > 1 for longer than 5 days) are associated with a Siberian/East Asian trough, while short events are not. The frequency of long-duration 500 hPa EOF2+ occurrence is found to be 1.1 and 2.6 per season (November to March) following Octobers of low and high snow cover extent (SCE) over Eurasia, respectively, or high and low autumn sea ice concentration (SIC) from the Greenland Sea to the Kara Sea, respectively. The occurrences of long events are more likely initiated when the zonal-mean zonal wind (60–70° N) is reduced in the lower stratosphere, with the Siberian trough deepened and the Alaskan ridge enhanced (i.e., amplified stationary eddies). The anomalies grow rapidly after initial perturbations and move westward, leading to a deep trough anomaly and a “wavier” jet stream over North America. Meanwhile in the stratosphere, an enhanced ridge over the Bering Strait and Alaska is accompanied by a downstream trough, which extends to the surface over Canada. It is suggested that the frequency of North American cold waves may be modulated by the interannual variations of snow cover and sea ice through perturbations to the zonal mean zonal wind and stationary eddies. Full article

Lake Baikal is a UNESCO World Heritage Site and the largest freshwater reservoir on the planet. It is located in the center of Eurasia, in an industrially developing region—Eastern Siberia. Although a regulatory and legal framework exists, quantitative estimates of the pathways of pollutant transport from industrial sources to the lake water area remain insufficiently studied, particularly in the context of seasonal dynamics and the influence of developing industrial sectors. In the present work, a quantitative analysis of the direct atmospheric transport of pollutants from three groups of stationary sources (the Irkutsk agglomeration, the Republic of Buryatia, and the oil-and-gas production areas of Irkutsk Oblast) to the lake surface was carried out for the first time using the HYSPLIT model for the period 2005–2025. About 4.7 million forward trajectories were computed at three heights (250, 500, 1000 m AGL) for each group of sources. It was established that conditions favorable for the transport of impurities to the lake occur in more than half of the cases. However, the spatial distribution of the impact on the Baikal air basin is heterogeneous: the Irkutsk agglomeration accounts for 67.5% of the “hits” (the main contribution being to the air basin of the Southern Basin), the Republic of Buryatia 18.8% (to the Central Basin), and the oil-and-gas areas 19.9% (to the Northern Basin). On the basis of a multifactor analysis, a combined Potential Impact (PI) index was developed that makes it possible to rank regional sources by the degree of their impact on the lake ecosystem, taking into account the emission volume, the probability of delivery, the residence time, and the height of trajectory passage. The results form a scientific basis for optimizing the spatial placement of environmental monitoring networks and for preliminary zoning of environmental risk assessment over the Lake Baikal water area. Ultimately, this study contributes to the sustainable management of the Baikal Natural Territory by providing actionable insights for balancing regional industrial growth with the long-term ecological preservation of the planet’s largest freshwater reservoir. Full article

African swine fever (ASF) poses a persistent and escalating threat to global swine production. To comprehensively characterize its global spatiotemporal dynamics from 1996 to 2025, we developed an integrated framework combining multi-distance spatial analysis and advanced time series forecasting, utilizing a dataset of 57,253 outbreak records. Our findings reveal a clear divergence in transmission patterns: wild boar accounted for approximately 70% of outbreaks and predominantly sustained transmission in Eastern Europe, whereas domestic pig outbreaks were largely concentrated in Southeast Asia. A pronounced epidemiological shift occurred between 2017 and 2020, during which ASF spread transitioned from a predominantly north–south axis linking Africa and the Caucasus to a broad east–west expansion across Eurasia, coinciding with rapid dissemination throughout Asia. In the Northern Hemisphere, ASF outbreaks exhibited a bimodal seasonal pattern, with peaks observed in January–March and July–August. Comparative forecasting analyses demonstrated that machine learning approaches consistently outperformed both traditional statistical and deep learning models. Among these, the random forest algorithm achieved the highest predictive accuracy, surpassing SARIMA, Prophet, XGBoost, and GRU. Collectively, these findings underscore the pivotal role of wild boar in maintaining global ASF transmission and highlight the necessity of integrated surveillance at wildlife–livestock interfaces. Furthermore, they support the application of machine learning-based approaches for improving early warning systems and enhancing the effectiveness of global ASF control strategies. Full article

The Greater Caucasus is one of the most extensively glacierized mountain systems in mid-latitude Eurasia and has experienced substantial glacier retreat in recent decades. Continuous monitoring using high-resolution satellite observations is therefore essential for accurately quantifying ongoing and future changes. In this study, we present a new glacier inventory for 2025 derived from high-resolution (3 m) PlanetScope satellite imagery combined with topographic information from the 30 m Advanced Land Observing Satellite (ALOS) Global Digital Surface Model (2006–2011). A total of 101 cloud-free PlanetScope scenes, acquired primarily during August–September 2025, were manually delineated to ensure precise glacier boundary detection. Regional climatic data, including summer temperature and winter precipitation from the ERA5 reanalysis, were compiled to support interpretation of glacier changes since the 1960s. The new inventory identifies 2341 glaciers covering 964.0 ± 22.8 km² across the Greater Caucasus. Glacier distribution is highly uneven: most of the glacier-covered area is found in the Central Caucasus (730.2 ± 15.5 km²), whereas considerably smaller glacierized areas occur in the Western and Eastern sectors. Most glaciers are located on northern slopes (687.7 ± 16.0 km²), reflecting strong topographic and climatic asymmetry. Mean glacier elevations range from ~3300 to 3600 m a.s.l., increasing eastward in response to decreasing precipitation. Size-class analysis shows that small glaciers (<0.5 km²) dominate numerically, whereas a limited number of large valley glaciers (>5.0 km²) contribute disproportionately to total glacier area. Comparison with previous inventories indicates continued and accelerated glacier retreat, particularly since 2014, with a mean area loss rate of −1.8% yr⁻¹. These comparisons further show that a total of 965 glaciers (~122.9 km²) have become extinct across the Greater Caucasus since the 1960s. This trend is primarily driven by increasing summer temperatures and declining winter precipitation. This high-resolution inventory provides the most detailed glacier dataset currently available for the Greater Caucasus and establishes an updated benchmark for future glacier monitoring, climate change studies, and hydrological assessments. Full article

Wildfires are among the key drivers of transformation in boreal ecosystems; however, the mechanisms of postfire recovery in the arid regions of Eurasia remain insufficiently understood. The aim of this study was to identify the role of burn severity and associated edaphic and hydrological factors in shaping the natural regeneration trajectories of Scots pine forests in the Kostanay region of northern Kazakhstan. This study is based on the integration of field data on seedling regeneration and soil conditions with the analysis of long-term satellite-derived indices (NDVI, NDMI, and NBR). Sample plots were grouped according to fixed burn severity classes, which enabled a consistent statistical comparison and reduced the interpretative ambiguity that has characterized previous studies in the region. The results indicate that pine forest regeneration is most successful under low and moderate burn severity, where seed sources are preserved and favourable moisture conditions are maintained. In contrast, high burn severity leads to a reduction in regenerative potential and a shift in recovery trajectories toward deciduous or sparsely vegetated communities. The spectral indices derived from the remote sensing data strongly agreed with the field-based indicators, confirming their suitability for assessing postfire vegetation dynamics. Soil properties act as important modifying factors of recovery processes, particularly under conditions of limited water availability. These findings enhance the current understanding of postfire recovery mechanisms in the arid part of the boreal zone and highlight the need for differentiated management of postfire landscapes. The integration of field observations with remote sensing data provides a robust framework for monitoring and forecasting recovery processes under an increasingly intensified fire regime. Full article

The Circum-Rhodope Belt fringes the Rhodope and Serbo-Macedonian zones in the Alpine orogen of the northern Aegean region. This belt contains Late Paleozoic and Mesozoic metasedimentary successions that record depositional history along the continental margin of Eurasia. Critical successions of the eastern Circum-Rhodope Belt, such as those exposed in the Fanari and Petrota areas, are studied here, integrating their structure, whole-rock geochemistry and U-Pb LA-ICP-MS zircon geochronological context. The Fanari turbiditic succession contains quartz arenite, while the Petrota succession consists of Fe-rich shale and sandstone, and both successions are distinguished by REE-depleted and REE-enriched characteristics and acidic and intermediate arc-related sedimentary sources, respectively. Detrital U-Pb zircon geochronology reveals a Late Carboniferous–Early Permian maximum depositional age of 301.2 ± 8.4 Ma for Fanari quartz arenite and a Late Jurassic maximum depositional age of 147.0 ± 2.0 Ma for Petrota Fe-shale. The results are interpreted in terms of Late Paleozoic continental slope deposition of the Fanari succession along the Eurasian margin and trench-arc sedimentation of the Petrota succession linked to the development of a Jurassic island arc system pertinent to the eastern Circum-Rhodope Belt. These tectonic settings and depositional environments can be used to restore an overall picture of a Late Paleozoic to Mid-Mesozoic sedimentation at the Rhodope–Serbo-Macedonian continental margin of Eurasia. Structures that developed in greenschist facies conditions and N-directed kinematics of the studied successions unequivocally relate them to other units of the eastern Circum-Rhodope Belt and its Late Jurassic tectonic evolution. Full article

Floods and droughts have increased in Northern Eurasia, probably caused by hydrological changes in other regions. We explore such hypothetical teleconnections by investigating environmental changes in two contrasting harsh environments: the Arctic Kara Sea and the arid Aral–Caspian region. Using long-term data from daily remote microwave sensing, we describe seasonal dynamics of temperature and moisture regimes in the two regions and hypothesize their inter-relationships from new analyses of wind data. For the first time, daily L-band satellite data were used to determine open water in the Kara Sea and long-term seasonal dynamics of brightness temperatures were used to relate variations in the ongoing aridization of the Aral Sea area and abnormal spring floods in the south of Western Siberia. Using soil moisture and Ocean Salinity satellite data, we discovered a previously unrecorded 4-year cyclicity of open-water periods for the Arctic seas and northern parts of the Caspian and Aral Seas. This cyclicity could impact climate forecasting in Northern Eurasia with significant societal implications. The main aim of this paper is to present new analyses that suggest possible mechanisms for teleconnections between the two contrasting harsh environments of Northern Eurasia. The hypothetical teleconnections now need to be tested. Full article

The Indian monsoon is an important component of the tropical climate system. Studies suggest that both precipitation from the NNU-2K AF experiments and Little Ice Age (LIA) proxy data reveal a significant 56-year period in the Indian summer monsoon (ISM). Volcanic activity influences the multi-year and decadal characteristics of Indian monsoon precipitation. A comparative analysis of multi-decadal variations in ISM precipitation from the AF experiments and the single-factor sensitivity experiments shows a correlation of 0.45 (p < 0.05), indicating dependence on volcanic activity. The 56-year period of ISM precipitation in the AF experiments is consistent with both the single-factor sensitivity experiments and precipitation influenced by volcanic activity. Further analysis reveals that cooling over Eurasia and warming of the Indian Ocean weaken the thermal contrast between land and sea, thereby reducing ISM intensity and decreasing ISM precipitation. Conversely, enhanced volcanic activity induces widespread cooling across the Northern Hemisphere, which shifts the Intertropical Convergence Zone (ITCZ) southward. This reduction in evaporative capacity and moisture content within the monsoon region ultimately decreases precipitation across the monsoon belt. Full article

A combination of fault and fracture analyses, paleostress reconstructions from calcite twins, and U-Pb dating of syn-kinematic calcite mineralization provides new insights into the Cretaceous–Tertiary tectonic evolution of the Provence fold-and-thrust belt. This approach helped unravel 90 million years of polyphase deformation in this belt, which represents the eastward continuation of the northern Pyrenees. Focusing on three main targets along an NNE-SSW transect oriented roughly parallel to the regional Pyrenean shortening (the southernmost Nerthe range, the Bimont Lake area, and the northern Rians syncline), we date a wide range of scales and natures of deformation structures such as stylolites, veins, mesoscale faults, and major thrust fault zones. The reconstructed long-lasting tectonic history includes (1) the Durancian uplift and related NNE-SSW extension (~110 to 90 Ma); (2) the ~N-S Pyrenean compression related to the convergence then collision between Eurasia and Iberia and the Corsica–Sardinia block (~80 to 34 Ma); the Oligocene E-W to WNW-ESE extension related to the West European Cenozoic Rift System (ECRIS) and the Oligo–Miocene NW-SE to NNW-SSE extension related to the Liguro-Provençal Rifting (LPR); and a middle-late (?) N-S to NW-SE Alpine compression. We show that the Pyrenean shortening in Provence occurred during two main phases, 81–69 Ma and 59–34 Ma, coeval with the inversion of the pre-Pyrenean rift and the main Pyrenean collision, separated by a tectonic quiescence as described in the Pyrenees. Together with the published literature, our U-Pb ages also support the overall northward (forelandward) in sequence propagation of Pyrenean shortening across Provence. Our U-Pb results further allow us to refine the interpretation of local and regional fracture sets and reveal unsuspected polyphase development of fractures sharing a common strike. Beyond regional implications, our study shows that sampling structures of various natures and scales for U-Pb geochronology is probably the most efficient strategy to encompass the entire time interval of deformation in fold-and-thrust belts. Full article

The Dingri–Gangba fault, a major structure within the Himalayan Orogenic Belt, records significant geological events, including the tectonic evolution of the northern margin of the Indian plate and the uplift of the Tibetan Plateau. However, its geometry, kinematics, and tectonic characteristics remain debated. To constrain the tectonic evolution of the Dingri–Gangba fault, this study integrates detailed field investigations and structural analysis with Electron Spin Resonance (ESR) dating to characterize its three-dimensional architecture and quantify the timing of its deformation phases. The results show that the fault trends nearly E–W and exhibits multi-phase structural superimposition, including thrusting (60–40 Ma), normal faulting (35–11 Ma), and strike-slip shear (18–6.8 Ma). These phases reflect a multi-stage tectonic evolution following the India–Eurasia collision. Stratigraphic comparisons reveal that during the Mesozoic, the Dingri–Gangba fault played a significant basin-controlling role, marked by variations in sedimentary thickness, soft-sediment deformation, and volcanic activity. The sedimentary evolution alternated between periods of “differentiation” and “uniformity”. A comprehensive analysis suggests that the tectonic evolution of the Dingri–Gangba fault is closely linked to the dynamic transition of the Tethys Himalaya from a passive continental margin to a collision orogeny, also reflecting changes in the tectonic stress field following the India–Eurasia collision. These findings provide valuable insights into the tectono–sedimentary–magmatic coupling along the southern margin of the Tibetan Plateau. Full article

The majority of research on food webs has focused on temperate lakes, and little is known about the food web of lakes in polar regions. Subarctic lakes are particularly sensitive to climate change, which affects their stability. Therefore, the trophic structure of the food web in such lakes was considered as the object of this study. We studied a clear-water oligotrophic lake located in the subarctic region of Eurasia, specifically in northern Karelia and the White Sea coast of Russia. The study examined both open water periods (summer–autumn) and ice-covered periods (winter–spring) in this lake. Stable isotope analysis of carbon (¹³C/¹²C ratio or δ¹³C value) and nitrogen (¹⁵N/¹⁴N, δ¹⁵N) in producers and consumers was applied and revealed significant seasonal variations in the structure of the food web. The results indicate the presence of both pelagic and littoral/benthic food web compartments, with a notable contribution of autochthonous carbon derived from benthic sources. Omnivorous fish (perch, Perca fluviatilis; vendace, Coregonus albula; nine-spined sticklebacks, Pungitius pungitius) and some benthic invertebrates (mayfly, Ephemera vulgata; bivalves, Sphaerium corneum) had intermediate δ¹³C values, integrating these compartments by obtaining resources from both. Planktonic invertebrates had significantly depleted ¹³C, with the lowest δ¹³C value reaching −41.7‰, indicating an important contribution of methane-derived carbon. The study also revealed close trophic relationships between lake invertebrates and cyanobacteria, namely with planktonic Dolichospermum lemmermannii and benthic Phormidium sp. Seasonal changes in δ¹⁵N values and in trophic position have been observed among predacious omnivorous fish and crustaceans (amphipods, Gammaracanthus loricatus, and copepods, Cyclops scutifer), which are capable of a generalist feeding strategy depending on food availability. Using the example of this lake, it can be concluded that polar lake ecosystems are characterized by different seasonal intakes of allochthonous organic carbon from wetland catchment (humic compounds) and nitrogen because of nitrogen fixation in the air by cyanoprocaryotes. Alternative energy sources, such as carbon derived from methane, can also contribute to the energy balance of lake ecosystems. This study contributes to our understanding of energy flow and connectivity between producers and consumers in high-latitude lakes. Full article

The origin of humans on Earth is closely linked to understanding how ancient populations dispersed into adjacent territories. Traditionally, studies have identified landscape and climatic changes as the primary factors in this dispersal. However, we propose that regional tectonic and geodynamic factors also played a significant role in shaping these movements. To analyze this phenomenon, we employed several primary methods, including radiometric dating, magnetostratigraphy, paleomagnetic correlation, isotope–oxygen analysis, tectonothermal studies, gravity mapping, paleobiogeographic assessment, lithofacies analysis, and event and cyclic stratigraphy. Our research indicates that the Akchagylian hydrospheric maximum, which reached up to +200 m, significantly limited the early dispersal of hominins from Africa to Eurasia. The migration corridor was shaped by tectonic activity between the Dead Sea Transform and the boundary of the Mesozoic Terrane Belt carbonate platform. We argue that, during the early stages of hominin evolution in East Africa, the Levantine Corridor (LC) had not yet developed into an optimal route for dispersal, either tectonically or paleogeographically. Suitable habitats for early hominins emerged only after the regression at the end of the Middle Gelasian, around two million years ago, when sea level fell by approximately 200 m, leading to the dissection of the coastal high plateau of the Eastern Mediterranean. We therefore suggest that the LC became established only after the termination of the Akchagylian transgression and the subsequent landscape reconfiguration of the Eastern Mediterranean. Our integrated analysis, combining paleomagnetic, structural, tectonic, and event stratigraphy data, indicates that the age of the renowned ‘Ubeidiya site in northern Israel is several thousand years older than previously thought. This paleogeographic impact had not been considered in earlier studies. Considering the diverse and complex factors that governed hominin dispersal from Africa into Eurasia within this multifaceted region, we propose that the scope of research should be broadened. Our detailed study of the Carmel area, located northeast of the Levantine Corridor and influenced by it during the Pleistocene, indicates that this region was inundated during the early phases of hominin migration out of Eastern Africa. Besides this, we have conducted an integrated geological–geophysical landscape analysis of the central part of the Israeli coastal plain. Full article

The taiga shrew (Sorex isodon), a boreal forest species widely distributed across northern Eurasia, had not previously been recorded in the Baltic states. We report the first occurrence of S. isodon in Lithuania, which extends the species range westward into the Baltic region. The specimen, which was initially misidentified as Sorex araneus, was collected in 2023 near Vilnius during non-systematic snap-trapping. A detailed examination of tail, cranial, and dental characteristics confirmed the identification as S. isodon. The individual was a non-adult male, weighing 5.8 g, and was trapped in a wet mixed forest influenced by beaver activity. This suggests that the microhabitat conditions are similar to those reported in Belarus and Ukraine. This finding extends the western boundary of S. isodon distribution by approximately 200–630 km. This study underscores the potential underreporting of this species in the Baltic region and highlights the importance of revisiting existing skull collections, conducting targeted trapping, and performing genetic analyses. Verifying additional records will clarify the habitat preferences and conservation relevance of S. isodon at the western edge of its range. Full article

Using station observations, the JRA-55 reanalysis dataset, and the CESM2 model, this study investigates the impacts of the stratospheric polar vortex (SPV) on winter near-surface wind speed (NSWS) over China across interannual and interdecadal timescales. On the interannual timescale, a strong SPV leads to a downward-extension signal that generates negative geopotential height anomalies over the Arctic, skewed toward the Atlantic sector. The associated surface response resembles the positive phase of the Arctic Oscillation (AO), resulting in reduced NSWS over northern China. In contrast, a weak SPV produces opposite effects. On the decadal timescale, a weakened SPV induces positive height anomalies over the Arctic that shift toward Northeast Eurasia. The surface response over the polar region stimulates a wave train, which drives a positive height anomaly over the North Pacific. The pressure gradient between East Asia and the North Pacific suppresses NSWS over eastern China. The response of China’s NSWS to interannual SPV variability is more pronounced than its response to interdecadal changes. CESM2 model simulations confirm these contrasting responses and the associated mechanisms. Full article

Atmospheric warming results in increase in temperatures for the mean, the coldest, and the hottest day of the year, season, or month. Global warming leads to a large increase in the atmospheric water vapor content and to changes in the hydrological cycle, which include an intensification of precipitation extremes. Using the GISS-E2.1 climate model, we present the future changes in the coldest and hottest daily temperatures as well as in extreme precipitation indices (under four main Shared Socioeconomic Pathways (SSPs)). The increase in the wet-day precipitation ranges between 6% and 15% per 1 °C global surface temperature warming. Scaling of the 95th percentile versus the total precipitation showed that the sensitivity for the extreme precipitation to the warming is about 10 times stronger than that for the mean total precipitation. For six precipitation extreme indices (Total Precipitation, R95p, RX5day, R10mm, SDII, and CDD), the histograms of probability density functions become flatter, with reduced peaks and increased spread for the global mean compared to the historical period of 1850–2014. The mean values shift to the right end (toward larger precipitation and intensity). The higher the GHG emission of the SSP scenario, the more significant the increase in the index change. We found an intensification of precipitation over the globe but large uncertainties remained regionally and at different scales, especially for extremes. Over land, there is a strong increase in precipitation for the wettest day in all seasons over the mid and high latitudes of the Northern Hemisphere. There is an enlargement of the drying patterns in the subtropics including over large regions around Mediterranean, southern Africa, and western Eurasia. For the continental averages, the reduction in total precipitation was found for South America, Europe, Africa, and Australia, and there is an increase in total precipitation over North America, Asia, and the continental Russian Arctic. Over the continental Russian Arctic, there is an increase in all precipitation extremes and a consistent decrease in CDD for all SSP scenarios, with the maximum increase of more than 90% for R95p and R10 mm observed under SSP5–8.5. Full article