The thermal coupling between the atmosphere and the subsurface on the Qinghai-Tibetan Plateau (QTP) governs permafrost stability, surface energy balance, and ecosystem processes, yet its spatiotemporal dynamics under accelerated warming are poorly understood. This study quantifies soil-atmosphere thermal coupling ((3) at the critical 0.1 m root-zone depth using in-situ data from 99 sites (1980-2020) and a machine learning framework. Results show significantly weaker coupling in permafrost (PF) zones (mean (3 = 0.42) than in seasonal frost (SF) zones (mean (3 = 0.50), confirming the powerful thermal buffering of permafrost. Critically, we find a widespread trend of weakening coupling (decreasing (3) at 66.7 % of sites, a phenomenon most pronounced in SF zones. Our driver analysis reveals that the spatial patterns of (3 are primarily controlled by surface insulation from summer rainfall and soil moisture. The temporal trends, however, are driven by a complex and counter-intuitive interplay. Paradoxically, rapid atmospheric warming is the strongest driver of a strengthening of coupling, likely due to the loss of insulative snow cover, while trends toward wetter conditions drive a weakening of coupling by enhancing surface insulation. Spatially explicit maps derived from our models pinpoint hotspots of accelerated decoupling in the eastern and southern QTP, while also identifying high-elevation PF regions where coupling is strengthening, signaling a loss of protective insulation and increased vulnerability to degradation. These findings highlight a dynamic and non-uniform response of land-atmosphere interactions to climate change, with profound implications for the QTP's cryosphere, hydrology, and ecosystems.

In light of a series of recent fatal landslides in Alaska, we set out to determine 1) the history of Alaskan landslides and 2) if the number of associated fatalities has increased with time. To answer our research questions, we searched a combination of 24 digital newspapers and online media sources, including historic digitized Alaskan newspapers, seeking landslides that affected people and/or infrastructure. This resulted in an inventory of 281 landslides occurring in Alaska since 1883. Our database includes the date on which the landslide occurred, its location and probable trigger, any reported injuries and/or fatalities, other reported damage, and the media source. Our inventory indicates that the number of reported landslides started to increase in the 1980's, and has increased dramatically in recent decades. We correlate the increase in landslides to a 1.2 degrees C to 3.4 degrees C increase in average annual air temperature and a 3% to 27% increase in precipitation over the last 50 years across Alaska. This change in climate is degrading permafrost, increasing the number of annual freeze/thaw events, and contributing to larger and more intense precipitation events - such as atmospheric rivers, all of which increase landslide susceptibility in various parts of the state. Alaska's last four fatal landslides occurred in Southeast Alaska, which has experienced the greatest increase in the number of landslides per capita. Our landslide database can serve as the initial inventory for analyses of landslides related to specific extreme weather events, as well as a resource to determine costs incurred from landslide-related damage.

In unsaturated soil mechanics, the liquid bridge force is a significant source of soil cohesion and tensile strength. However, the classical Young-Laplace equation, which neglects the stratified nature of water at the nanoscale, fails to accurately capture the physical and mechanical behaviour of nanoscale liquid bridges. This study utilizes molecular dynamics simulations to investigate the wetting behaviour and mechanical mechanisms of liquid bridges between particles at the nanoscale. The study proposes dividing the liquid bridge force into three components: surface tension, matric suction, and adsorption force, to explain the mechanics of nanoscale liquid bridges more comprehensively. The results demonstrate that water layers within liquid bridges exhibit discrete stratified structures at the nanoscale. Moreover, the mechanical behaviour of liquid bridges is highly dependent on pore water volume and pore spacing. Specifically, the contact angle is positively correlated with the pore spacing, while the liquid bridge force increases with the pore water volume and is inversely proportional to the pore spacing. As the separation distance increases, the liquid bridge force gradually diminishes until rupture occurs. This research expands the applicability of the classical Young-Laplace equation and offers new insights into the mechanical properties of unsaturated soils, particularly clays.

The increasing demand for sustainable agricultural practices has intensified interest in soilless cultivation systems. However, hydroponics is unable to provide mechanical support for plant roots, and traditional soilless cultivation substrates mostly suffer from poor water retention capacity, rapid nutrient loss, and difficulty in precise control. Hydrogel-based soilless cultivation substrates show great potential for application due to their excellent water absorption, water retention and adjustable transparency. In this study, P(AM-co-NIPAM)/gelatin composite hydrogels with adjustable pore structures, mechanical strength and transparency were obtained by regulating the concentration of crosslinker. Soybean seedlings were grown on these substrates to evaluate the effects of hydrogel properties on root and shoot growth. The results demonstrate that hydrogels with optimized crosslink density possess superior mechanical properties, enhanced water retention capacity, and adequate transparency, facilitating both robust plant growth and high-resolution root system observation. We found that under the MBA content of 0.05 %, the hydrogel matrix could significantly promote the growth of aerial part and root system of soybean seedlings, and was conducive to the colonization of root bacteria. This work highlights the potential of controlled hydrogel matrices in soilless cultivation as a sustainable solution to improve root growth environments, enhance resource utilization, and enable dynamic root system studies. Given their adjustable structure and compatibility with plant growth, such hydrogels may also serve as promising candidates for future application in soilless crop production systems, particularly in scenarios where water and substrate optimization are critical to sustainable agricultural practices.

Iron pipes connected by bell-spigot joints are utilized in buried pipeline systems for urban water and gas supply networks. The joints are the weak points of buried iron pipelines, which are particularly vulnerable to damage from excessive axial opening during seismic motion. The axial joint opening, resulting from the relative soil displacement surrounding the pipeline, is an important indicator for the seismic response of buried iron pipelines. The spatial variability of soil properties has a significant influence on the seismic response of the site soil, which subsequently affects the seismic response of the buried iron pipeline. In this study, two-dimensional finite element models of a generic site with explicit consideration of random soil properties and random mechanical properties of pipeline joints were established to investigate the seismic response of the site soil and the buried pipeline, respectively. The numerical results show that with consideration of the spatial variability of soil properties, the maximum axial opening of pipeline joints increases by at least 61.7 %, compared to the deterministic case. Moreover, in the case considering the variability of pipeline-soil interactions and joint resistance, the spatial variability of soil properties remains the dominant factor influencing the seismic response of buried iron pipelines.

The foundation conditions of piers for multi-span long-distance heavy-haul railway bridges inevitably vary at different locations, which may lead to non-uniform ground motions at each pier position, potentially causing adverse effects on the bridge's seismic response. To investigate the seismic response of bridges and the running safety of heavy-haul trains as they cross the bridge during an earthquake, a three-dimensional heavy-haul railway train-track-bridge (HRTTB) coupled system model was developed using ANSYS/LS-DYNA. This model incorporates the nonlinear behavior of critical components such as bearings, lateral restrainers, piers, and wheel-rail contact interactions, and it has been validated against field-measured data to ensure reliable dynamics parameters for seismic analysis. A multi-span simply supported girder bridge from a heavy-haul railway (HHR) was employed as a case study, in which a spatially correlated non-stationary ground motion field was generated based on spectral representation harmonic theory. Comparative analyses of the seismic responses under spatially varying ground motions (SVGM) and uniform seismic excitation conditions were performed for the coupled system. The results indicate that the presence of heavy-haul trains prolongs the natural period of the HRTTB system, thereby appreciably altering its seismic response. At lower apparent wave velocities, more piers exhibit a low-response state, and some pier bases enter the elastic-plastic stage under local site effects. Compared with the piers, the bearings show higher sensitivity to seismic inputs; fixed bearings experience damage when subjected to traveling wave effects and local site effects, which is subsequently followed by the failure of lateral restrainers. Train running safety is markedly reduced when crossing local soft soil site conditions. The conclusions drawn from this study can be applied in the seismic design and running safety assessment of HHR bridge systems under SVGM.

The spatial distribution of saturated hydraulic conductivity (Ks) is controlled by soil processes at multiple scales, and this spatial variability is crucial to simulating soil moisture movement. Nevertheless, few studies focus on the spatial variability of Ks and how changes through alpine meadow degradation or the specific scales at which the controlling factors function. This study therefore examines the scale-dependent relationships between Ks and several primary driving factors. Soil samples were collected at an interval of 3 m along three transects on a slope in the Qinghai-Tibet Plateau (QTP) and Ks, bulk density (BD), above-ground biomass (AGB), soil organic carbon content (SOC), sand content (SAND), silt content (SILT) and clay content (CLAY) were analysed. Ks showed strong spatial dependency and irregular distribution due to alpine meadow degradation. Pearson correlation analysis revealed a significant correlation between BD, AGB and Ks (p < 0.001). Furthermore, cross-semivariograms showed that Ks exhibited strong spatial correlation with AGB and SAND. Using the state space method, we determined that BD, SOC, AGB and CLAY are the main factors that control the spatial distribution of Ks on the slope. A two-factor state-space equation based on CLAY and BD provides a good representation of Ks, enabling the prediction and estimation of Ks distribution characteristics. These findings enhance our understanding of the crucial parameters that govern hydrological processes at the slope-scale of alpine grassland on the QTP, thereby helping to elucidate permafrost-related hydrological processes related to climate change.

Study region: Gandaki River basin in the central Himalayan region. Study focus: Spatiotemporal investigation of meteorological, agricultural, and hydrological droughts over historical (1986-2014) and future periods (2024-2100). New hydrological insights for the region: Historical analysis reveals that meteorological, agricultural, and hydrological droughts exhibit an insignificant increase in severity and duration. Agricultural and hydrological droughts are characterized by higher severity and longer duration compared to meteorological droughts. Regarding the impact of precipitation and temperature on agricultural drought severity, precipitation replenishes soil moisture in various ways across different elevation zones, thereby alleviating agricultural drought. Conversely, temperature primarily intensifies agricultural drought severity by reducing soil moisture through evaporation and transpiration. Glaciers play an important role in hydrological drought, with both precipitation and temperature helping to alleviate drought severity in subbasins containing glaciers. This phenomenon is particularly pronounced for subbasins with a glacier area ratio exceeding 10.5 %, showcasing a significant negative correlation between temperature and drought severity. Future projections show that meteorological and agricultural droughts, particularly in elevation zones below 3000 m, which cover 79.4 % of agricultural land, will become more severe and prolonged, threatening agricultural productivity. Climate change and glacier retreat are expected to increase hydrological droughts' severity and duration. These findings enhance understanding of drought evolution and highlight the urgent need for drought planning and management to protect socioeconomic development in the Central Himalaya.

The impact of climate change on vegetation ecosystems is a prominent focus in global climate change research. The climate change affects vegetation growth and ecosystem stability in the upper reaches of the Yellow River (UYR). However, the spatiotemporal patterns and driving mechanisms of vegetation growth status (VGS) in the region remain poorly understood. Based on the hydrological model PLS, an innovative WEP-CHC model was developed by integrating regional environmental and vegetation growth characteristics. Furthermore, combined with the PLS-SEM model and other methods, this study systematically investigated the spatiotemporal patterns and driving mechanisms of VGS in the UYR. The results indicated that: (1) VGS exhibited significant spatiotemporal variation trends within the study area. In the study period of 1970-2020, the GPP onset time was significantly advanced (p < 0.05) while the GPP peak value was significantly increased. Spatial analysis revealed significant spatial complexity in the GPP onset time and peak values across the region. (2) Soil freeze-thaw conditions significantly influenced VGS (p < 0.05). The complete thawing time of permafrost was closely coincided with the GPP onset time, with a correlation coefficient exceeding 0.84. After controlling soil freeze-thaw effects using partial correlation analysis, it was found that better initial soil hydrothermal conditions would lead to better VGS; (3) The model constructed with annual hydrothermal conditions (AHC), soil freeze-thaw period (SFTP), vegetation growth season (VGS), initial soil hydrothermal conditions (ISHC), and annual solar radiation conditions (ASRC), demonstrated good explanatory power for vegetation growth. The R 2 values of PLS-SEM were above 0.76 in all five subregions. However, their effects on VGS varied significantly across subregions. Overall, AHC and SFTP were the dominant factors in all subregions. Furthermore, the impacts of ISHC and VGC were statistically insignificant, whereas the effects of ASRC exhibited high complexity. This study not only provides new insights into the current state of hydrological-ecological coupling in the UYR but also offers a new tool for ecological conservation and sustainable water management in other cold regions and similar watersheds worldwide.

We present a high-resolution geologic map of the Rubin crater region, located on Mons Amundsen, which has been identified as a promising site for future lunar exploration (AOI E in Wueller et al., 2024). We developed a design reference mission (DRM) to highlight the region's potential for addressing key lunar science goals, particularly those related to the early lunar bombardment history, lunar crustal rocks, volatiles, impact processes at multiple scales, and regolith properties, as outlined by the National Research Council (2007). The Rubin crater, which formed about 1.58 billion years ago during the Eratosthenian period, excavated material from depths of up to 320 m, potentially reaching the underlying South Pole-Aitken (SPA) massif, Mons Amundsen. This makes the crater's ejecta material, along with the Amundsen ejecta covering the massif, prime targets for sampling SPA-derived materials that can expand our understanding of early Solar System dynamics and the lunar cratering chronology. Additionally, the region hosts several permanently shadowed regions (PSRs), ideal for studying potential lunar volatiles and the processes affecting their distribution. The DRM proposes nine traverse options for exploration via walking EVAs, the Lunar Roving Vehicle (LRV), and LRV-assisted EVAs, with traverse lengths ranging from 3.6 km to 18.2 km. Each traverse is designed to sample diverse geologic units and address multiple scientific objectives. Given its scientific potential and favorable exploration conditions, the Rubin crater region is an ideal location for testing south polar landing operations, potentially paving the way for more complex missions, such as a Shackleton crater landing. (c) 2025 The Author(s). Published by Elsevier B.V. on behalf of COSPAR. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).