Search Results (668)

Urban public spaces in cold-climate cities commonly face the challenge of seasonal vitality attenuation. Taking the central urban area of Shenyang as a case study, this paper constructs a HEVA four-dimensional framework based on “spatial diagnosis, mechanism analysis, and design response.” By integrating Multiscale Geographically Weighted Regression (MGWR) with GIS spatial analysis, the study reveals the spatial heterogeneity and driving mechanisms of winter vitality attenuation in linear green spaces. The findings are threefold: (1) Winter wind fields induce significant local wind-chill effects that severely suppress winter stay vitality in green spaces; (2) MGWR results show that greenery coverage exhibits a predominantly positive effect (approximately 81% of sample points have positive coefficients), bus stop density exhibits a “bifurcated spatial pattern”, with positive coefficients at approximately 53% of sample points and negative at the remaining 47%, indicating a highly localized effect., commercial service density is positive across the entire study area (100% positive), building density is predominantly negative (approximately 87%), and road network density has a relatively weak effect; (3) Based on the above mechanisms, a three-pronged elastic design strategy system is proposed, encompassing “climate-adaptive regulation, functional composite implantation, and regional cultural response.” This study explores a data-driven, mechanism-guided geospatial design pathway for the renewal of underperforming spaces in cold-climate cities. The generalizability of the methodological framework warrants further validation through multi-city and multi-seasonal data. Full article

Water-retaining roller-compacted concrete (RCC) dams suffer severe deterioration under coupled moisture ingress and freeze–thaw (F-T) cycles. To elucidate the damage mechanisms, this study employed industrial X-ray computed tomography (CT) synchronized with uniaxial compression and acoustic emission (AE) monitoring. The cross-scale damage evolution of RCC was investigated under dry, water-saturated, 25, and 50 F-T cycle conditions. The results indicate the following: (1) Macroscopically, F-T damage causes linear peak stress attenuation, shifting the failure mode from brittle axial splitting to ductile oblique shear. (2) Mesoscopically, frost-heaving stress expands native mesopores (500–2500 μm), increasing their volume fraction from 8.45% to 14.86% and remodeling isolated voids into a 3D interconnected defect network. (3) Microscopically, GMM-based AE clustering reveals a fracture transition. Driven by moisture lubrication and defect propagation, global shear cracks surpass the 50% threshold at 25 cycles (53.5%), reaching 68.6% at 50 cycles. (4) For cross-scale mapping, calibrating the AE b-value via Aki’s method decouples pore-water signal attenuation. Its pre-peak characteristic (an initial decrease followed by a rebound) accurately maps microcracks unstably coalescing along interconnected pores to form macroscopic shear planes. This cross-scale mechanism provides a scientific paradigm for condition monitoring of massive concrete in cold regions. Full article

Large mineral flotation workshops in severe cold regions represent special industrial indoor environments characterized by the coexistence of limited ventilation and intense heat release. Such conditions generate pronounced spatial thermal stratification and localized heat accumulation within the workshop, leading to uneven worker thermal exposure and increased thermal discomfort and heat stress risk. However, conventional thermal comfort models were primarily developed for ordinary buildings with relatively stable thermal environments. Their applicability to large industrial workshops remains insufficiently validated. Nine representative monitoring points were arranged in the summer operating areas of the workshop, and thermal comfort surveys were conducted among 35 workers who had adapted to the local climate and working environment. The predicted mean vote (PMV) model was used as the baseline assessment framework, while an adaptive predicted mean vote (aPMV) model was further calibrated using field-based thermal sensation information. Monte Carlo simulation was employed to evaluate uncertainty propagation under field-data constraints, and Sobol sensitivity analysis was conducted to identify the dominant factors affecting thermal comfort predictions. The results demonstrated that the conventional PMV model exhibited a clear warm prediction bias under the investigated industrial conditions. After adaptive correction, the deviation from the field-based TSV was reduced by 82.93%, indicating improved agreement with workers’ actual thermal perception. Sensitivity analysis identified metabolic rate as the dominant contributor to aPMV output variance, with first-order and total-effect Sobol indices of 0.530 and 0.535. The proposed framework provides a scenario-specific approach for thermal comfort assessment in the investigated flotation workshop and offers preliminary methodological references for similar large-scale flotation workshops. Full article

Future climate projections suggest an increase in heat-related mortality and a decrease in cold-related deaths under warming scenarios. Understanding the health impacts of extreme heat, and their implications for healthcare demand is essential for assessing the future burden of climate-related illnesses. In this study, we examined the relationship between extreme heat events and Emergency Department Visits (EDV) for heat-related illnesses (HRIs) across the United States from 2018 to 2025. Using data from the Centers for Disease Control and Prevention (CDC) Heat and Health Tracker and other relevant sources, we analyzed EDV rates standardized to 100,000 population. We aggregated daily into the 10 U.S. Health and Human Services (HHS) Regions. We used 0.5° × 0.5° gridded maximum daily temperature data (aggregated to HHS regions with proportional area weighting) and daily maximum heat index extracted from the CDC data portal (estimated using the US National Weather Service methodology and aggregated to HHS regions using total population weighting) to characterize seasonal patterns and regional variability. The association between peak heat events and EDV time series was explored using log-linear mixed-effects models, which accounted for seasonal trends, climate variables, and their regional variability. Random effects were used to capture regional heterogeneity in predictor-response relationships, accommodating variation in associations across regions. Model performance was evaluated using prediction error metrics and goodness-of-fit assessments. Maximum temperature and heat index were both significant predictors, with the heat index offering a slightly better fit. Associations were largely contemporaneous, with peak correlations at lag zero, underscoring the need for real-time response. EDV increased several days before peak environmental conditions, consistent with early exposure effects. While temperature-EDV relationships varied regionally, heat index associations were more stable. This work underscores the urgent need for regionally adaptive public health strategies in the face of intensifying climate extremes and outlines future directions for research and policy to strengthen health systems’ preparedness in a warming world. Full article

Provincial cold-chain investment decisions must reconcile food-loss prevention, digital visibility, logistics capability and the environmental burden of freight-intensive growth. This study develops a sustainability-oriented readiness–intensity framework for 31 provincial-level regions in mainland China. The baseline model uses 14 auditable public-data criteria and combines Criteria Importance Through Intercriteria Correlation (CRITIC) with the standard Combined Compromise Solution (CoCoSo) algorithm. Because the observations combine 2024 statistics, a 2023 digital-finance index and the cumulative 2020–2025 cold-chain-base list, the design is described as an asynchronous cross-sectional snapshot rather than a single-year panel. Municipal sewage and green-space variables are interpreted as regional enabling capacity, not direct cold-chain environmental performance; road freight turnover relative to gross domestic product is treated as a cost-type freight-intensity transition-pressure proxy. A separate diagnostic replaces the earlier inverse-size term with logistics residuals conditional on agri-food output. Shandong, Guangdong, Jiangsu, Henan and Zhejiang form the leading demonstration-readiness group. Equal-weight CoCoSo closely matches the CRITIC result (Spearman ρ = 0.996), while TOPSIS and VIKOR retain the broad ordering but expose local method sensitivity. Dropping either digital criterion, removing the three indirect green proxies, winsorizing the normalization range, varying the CoCoSo compromise parameter and substituting 2022 digital data do not alter the leading pattern. Under an assumed 5% indicator-error perturbation, Shandong and Guangdong remain within ranks 1–2, whereas the ordering of several adjacent provinces is less secure. The framework supports sequenced investment packages rather than a deterministic league table and distinguishes demonstration-ready, scale-led, intensity-led and coverage-building contexts. Full article

Fine-aggregate source can alter both the load-bearing response and surface scaling of mortar under freezing and thawing, but these responses are often reduced to a single durability ranking. This study compared coal gangue sand mortar (CGM), river sand mortar (RSM), desert sand mortar (DSM), and standard sand mortar (StSM) after 0, 25, and 50 freeze–thaw cycles (FTCs). Compressive strength and mass loss were measured using three replicate specimens per quantitative condition, while post-compression fragments were examined by scanning electron microscopy (SEM). The primary integrative analysis was a parameter-free two-dimensional damage-trajectory map that retained absolute compressive strength and mass loss as separate measured axes; a weighted coupled index was retained only as an auxiliary sensitivity check. Before cycling, the compressive strengths of StSM, RSM, DSM, and CGM were $68.13\pm 0.48$, $53.90\pm 0.39$, $19.47\pm 0.33$, and $6.49\pm 0.07$ MPa, respectively. After 50 FTCs, StSM retained the highest absolute strength ($33.61\pm 0.39$ MPa) and the lowest mass loss ($0.21\pm 0.02\%$), whereas DSM retained $9.91\pm 0.19$ MPa and exhibited the highest mass loss ($17.46\pm 0.05\%$). The StSM trajectory moved primarily toward lower strength with negligible surface-material loss, while DSM moved toward both low residual strength and severe scaling. RSM showed substantial strength reduction followed by later-stage surface loss. CGM followed an atypical trajectory in which measured strength increased to $11.13\pm 0.13$ MPa while mass loss reached $9.67\pm 0.04\%$; because age-matched non-frozen controls were unavailable, this apparent gain cannot be separated from continued hydration and specimen-age effects. The SEM images suggested pores, interfacial discontinuities, cracking, and matrix loosening, although some defects may have been induced or widened by compression. The trajectory representation exposed distinct deterioration modes without arbitrary weighting, whereas the calculated ordering of CGM and RSM in the auxiliary index changed with weighting and normalization choices. The results support reporting absolute residual strength and surface loss jointly when screening alternative fine aggregates for cold-region mortar. Full article

This study investigates the long-term impacts of climate change on crop yields by analyzing global historical data from 1961 to 2024 across 25 selected countries, to to reveal how historical weather patterns affected crop yields in the most vulnerable regions of the world. Utilizing crop yield data from FAOSTAT and weather time series from the World Bank Climate Knowledge Portal, three distinct climate risk groups of countries were defined: Group 1 (strong warming, stable precipitation), Group 2 (no significant warming, strong precipitation decrease), and Group 3 (mild warming, strong precipitation decrease). A Linear Mixed-Effects Model (LMM) was employed to quantify the non-linear impacts and interactions of climate variables, including annual temperature maximums, minimums, precipitation, warm and cold spell durations, and the Standardized Precipitation Evapotranspiration Index, on primary staple and cash crops. Results reveal a stark regional asymmetry. In temperate regions (Group 1), agrotechnological advancements have successfully cushioned climate shocks over the past decades, although this buffering effect faces biophysical limits due to non-linear temperature thresholds, particularly for root crops like potatoes and sugarbeet. In tropical–subtropical areas (Group 2) and the Mediterranean (Group 3), climate extremes exert severe pressure on vital crops. Prolonged warm spells significantly reduce yields for perennials like bananas, coffee, and dates, while other Mediterranean crops like olives thrive under longer warm spells. While country-specific institutional capacities often generate substantial yield heterogeneity, major exceptions emerge for staple crops like wheat in Group 2 and barley in Group 3, where low Intraclass Correlation Coefficients (ICC) demonstrate that regional climatic drivers override national boundaries. The findings underscore that universal climate strategies are inefficient, and policymakers must prioritize crop-specific and localized adaptation frameworks for future food security. Full article

In the event of a nuclear or volcanic winter, up to two-thirds of sunlight could be blocked (abrupt sunlight reduction scenarios, ASRS), leading to a worldwide crop failure. There are some similarities between such effects and the short northern summer. This suggests the possibility of transferring successful agricultural practices validated in high latitudes to tropical regions, especially low-tech solutions, which can be more easily implemented in the case of a global catastrophe. We show that equatorial regions’ temperatures under a 150 Tg (millions of tonnes of soot to the stratosphere) scenario of nuclear winter (around 15 °C average) are similar to summer temperatures in northern European regions of the former Soviet Union, which had functional agriculture. We identified the following main agricultural technologies which can be adapted: (a) cold-tolerant crops, first of all potatoes, but also rutabaga and fodder beet; (b) frost-protection technologies (night-covering, watering, bottles with water); (c) silage production in pits for animal feeding; (d) and low-labor-demanding crops. One meta lesson is making several bets on different food-producing technologies in the situation of risky agricultural practices. These findings contribute to Sustainable Development Goal 2 (Zero Hunger) and highlight how historically validated, low-input agricultural knowledge can underpin sustainable food system resilience under extreme climate disruption. Full article

Most studies have explored the impact of different types of local climate zones (LCZs) on energy consumption, but few have examined climate differences within intra-local climate zones (intra-LCZs) and the impact of cold waves (CW) on energy consumption. This study conducted a 150-day long-term observation of air temperature (Ta) and relative humidity (RH) in six LCZs in Shenyang, a severe cold region, to examine climate differences within intra-LCZs and the influence of CW and the urban heat island (UHI) on energy consumption. The results show that the temperatures and heating energy consumption in 5 LCZ4s exhibited a clear gradient from the urban core to the suburbs. During CW, the differences increased, and the nighttime differences were more pronounced. CW significantly increased residential heating energy consumption, whereas the urban heat island (UHI) reduced it in urban areas. Additionally, there was a clear positive correlation between UHI and the urban-suburban energy consumption difference. Under the combined effects of CW and UHI, the average daily cumulative heating energy consumption in urban areas (CW) was much higher than in suburban areas during non-cold-wave (NCW) periods, increasing by 69.2–85.9%. This study provides empirical evidence for energy conservation and strategies for responding to extreme weather events. Full article

Optimizing outdoor thermal environments is essential for sustainable urban development and spatial resilience. Existing urban microclimate studies generally adopt the 1.5 m pedestrian height to represent outdoor thermal conditions. However, this widely accepted assumption has not been verified in multi-level campus spaces with terrace-induced complex three-dimensional environments, particularly in severe cold climate zones. This study investigates vertical thermal stratification and the relative influences of orientation, surface material, and height in Changchun, China. Field measurements at four levels were integrated with ENVI-met simulations calibrated against six independent validation sites. During summer peak hours, orientation dominates the thermal regime, outweighing both material and height. The peak thermal load shifts vertically from the south at lower elevations to the west at upper levels, generating a maximum air temperature difference of 1.66 °C compared to the consistently coolest east-facing terraces at 14:00. The vertical temperature profile does not follow a simple trend but varies with the surrounding geometry. Mid-level thermal trap appears near 3.5 m in the semi-enclosed building, where air temperature peaks before declining toward the roof. Moreover, an idealized model shows monotonic cooling with height, confirming that local obstructions cause the observed heat accumulation. During summer peak hours, surface material exerts a highly limited direct effect on ambient air temperature within these well-mixed three-dimensional spaces. Differences among concrete, asphalt, wood, and turf stay below 0.1 °C, roughly two orders of magnitude smaller than the orientation-driven contrast, because turbulent mixing and façade radiation overwhelm local surface heat fluxes. The findings highlight the inadequacy of evaluating thermal conditions at a single height, and challenge the conventional assumptions that material substitution is the primary heat mitigation measure in multi-level environments and that building orientation plays only a minor role in microclimate regulation. All quantitative outputs stem from ideal courtyard shapes and cloudless summer scenarios, reflecting mechanistic microclimate patterns instead of globally applicable predictive metrics. Local validation is mandatory before extending these conclusions to other seasons or building typologies. For sustainable summer thermal regulation on multi-level campuses, this work highlights orientation and adaptive shading as primary design measures, while material configuration acts only as auxiliary fine-tuning. Full article

Reliable flood simulation in large cold-region basins requires understanding how meteorological forcing differences propagate through runoff generation and river routing. We compared CMFD, GSWP3v1, and CRUNCEPv7 using a controlled, uncalibrated offline CLM5–CaMa-Flood framework for the Songhua River Basin during 1996–2014, with all non-forcing settings fixed. Evaluation included daily and monthly discharge, seasonal hydrographs, annual maximum daily discharge (AMAX), observed Q95/Q99 thresholds, selected 1998 and 2013 warm-season high-flow cases, runoff-process diagnostics, event-window sensitivity tests, 5000 paired year-wise bootstrap resamples, and auxiliary water-level anomalies. CMFD generally produced the highest r, KGE, and daily NSE, but also the largest positive long-term Bias. CRUNCEPv7 systematically underestimated discharge, whereas GSWP3v1 more often yielded the smallest absolute Bias. For both selected events, CMFD reduced peak and volume underestimation, although peaks remained smoothed and delayed. Event-window precipitation differences did not translate proportionally into CLM5 runoff, and the larger CMFD response involved increases in both surface runoff and subsurface drainage. The event-magnitude ordering remained stable across ±30-, ±45-, and ±60-day windows. Bootstrap results showed a robust CMFD advantage over GSWP3v1 for temporal agreement and efficiency, while several CMFD–CRUNCEPv7 comparisons remained sample-dependent. Forcing-product performance was therefore scale-, metric-, and target-dependent and conditional on the fixed model configuration. Full article

Water scarcity strongly constrains the revegetation of disturbed mine substrates in cold-arid regions. This study compared soil-moisture dynamics between a microtopographic reclamation area and an adjacent flat reclamation area in an abandoned stone quarry within the Kalamaili Ungulate Nature Reserve, northwestern China. The integrated restoration treatment, established in 2018, combined linear trenches 30–40 cm deep and spaced 60 cm apart, native seed sowing, transferred seed-bank topsoil, and water-retaining material. From January to December 2024, sensor-derived apparent volumetric water content was monitored at five depths—0–10, 10–20, 20–30, 30–40, and 40–50 cm—at 10 min intervals using sensors operated with the manufacturer’s standard calibration. Following quality control and temporal synchronization, 41,475 valid timestamps were retained for each monitored profile. The study provides a continuous full-year, multi-depth record from an unirrigated, cold-arid reconstructed quarry substrate, a setting that remains underrepresented in previous micro-catchment and dryland-restoration research. However, this study is based on a single hydrological year and does not directly measure plant physiological responses or long-term restoration outcomes. Therefore, elevated soil moisture should be interpreted as a preliminary indicator of restoration potential rather than a definitive measure of ecological recovery success. The monitored microtopographic profile maintained higher mean apparent water content than the flat profile during most of the year. The largest annual relative profile difference occurred at 10–20 cm depth, reaching 18.0%, followed by 11.7% at 0–10 cm, whereas differences decreased below 20 cm and reached 1.9% at 40–50 cm. During selected rainfall and probable snowmelt periods, the microtopographic profile exhibited larger wetting responses and slower post-event recession. These patterns indicate contrasting upper-profile wetting and drying dynamics between the two monitored reclamation configurations. However, runoff, infiltration, evaporation, snow accumulation, soil-water potential, and vegetation responses were not measured directly. Moreover, monitoring began several years after vegetation establishment, and trenching, seed addition, seed-bank transfer, and water-retaining material were not evaluated independently. The findings should therefore be interpreted as a site-specific post-establishment comparison rather than evidence of the isolated effect of microtopography. Replicated, multi-year studies are required to determine the mechanisms, effectiveness, and broader transferability of this integrated reclamation configuration. Full article

Permafrost peatlands in high-altitude regions store substantial amounts of organic carbon, yet the biogeochemical consequences of thermokarst collapse remain poorly understood. Using a space-for-time substitution approach, we selected four habitats representing a thermokarst development sequence in the Altai Mountains peatlands—slightly collapsed peat mounds (P1), severely collapsed peat mounds (P2), thawed herbaceous peat (PB1), and thermokarst ponds (PB2)—and conducted in situ greenhouse gas flux monitoring, soil physicochemical analysis, enzyme activity assays, and structural equation modeling. We found that thermokarst development fundamentally altered the greenhouse gas source–sink balance through three interconnected mechanisms. First, CO₂ fluxes shifted from net emission in P1 (684.1 mg m⁻² h⁻¹) to net uptake in PB2 (−25.6 mg m⁻² h⁻¹), driven primarily by the oxidative loss of mineral-associated organic carbon in the 40–60 cm layer (71.3% loss), whereas lateral dissolved organic carbon export accounted for only 12.3% of total carbon loss. Second, CH₄ fluxes in PB2 (3.8 ± 0.7 mg m⁻² h⁻¹) reached approximately 43% of the theoretical maximum, with this suppression associated with phosphorus limitation (total phosphorus < 0.05 g kg⁻¹) and a marked reduction in alkaline phosphatase activity. Third, N₂O uptake increased along the thaw sequence to −28.6 μg m⁻² h⁻¹ in PB2, with the 40–80 cm layer contributing 42% more than the surface layer. This increase in N₂O uptake occurred when the soil C/N ratio exceeded 300, a threshold that reflects the substantial stoichiometric imbalance between carbon and nitrogen following thermokarst development. These findings demonstrate that the transition from peat mounds to thermokarst ponds alters the net greenhouse gas source–sink balance through changes in MAOC stability, phosphorus availability, and carbon-to-nitrogen stoichiometry. Our results provide empirical constraints for evaluating carbon-climate feedbacks in cold-region peatlands. Full article

East Asian spring dust activity has generally weakened since the early 2000s (Theil-Sen trend −1.07 × 10⁻⁶ yr⁻¹, significant over 62% of the domain), but severe events continue to occur when synoptic forcing, source-region dryness, and terrain-guided transport are favorably coupled. This study places the 19–23 March 2023 East Asian dust storm within this 2000–2024 background and provides an integrated three-dimensional analysis of its transport, vertical structure, and topographic controls. The event developed as a dual-source relay-convergence process: Taklamakan Desert dust was emitted first on 19 March and transported southeastward along the Hexi Corridor, while Mongolian Plateau dust intensified on 21 March and mainly affected North China. Independently calibrated, PM10-cross-validated FLEXPART-WRF trajectory arrays (R = 0.74–0.81) show Taklamakan contributed 100% of the calibrated near-surface dust mass at Lanzhou and Mongolian 98% at Beijing during each receptor’s event peak window. Four independent dynamical diagnostics quantify topographic control, showing the Helan Mountains attenuate westward-approaching Taklamakan dust by 23% across the range. TROPOMI AAI, CALIPSO, ground PM10, and CAMS EAC4 jointly corroborate multi-level cold-vortex/trough-frontal coupling and terrain blocking as the controlling mechanisms, demonstrating that extreme dust episodes can still occur under a weakening long-term background when dynamic lifting, dual-source activation, and topographic channeling act together. Full article

To elucidate the response characteristics of radial growth and water use strategies in coniferous forests of cold-arid regions to drought stress, this study focused on Larix sibirica in different forestry areas of the Altai Mountains. Using dendrochronology and stable isotope techniques, we calculated the basal area increment (BAI) and intrinsic water-use efficiency (iWUE), and combined these with the standardized precipitation–evapotranspiration index (SPEI) to identify drought events, to investigate tree growth and water-use efficiency responses to climate variability. The results showed that drought years were characterized by reduced radial growth and increased iWUE in Larix sibirica across both forest regions, and tree-ring-derived intercellular CO₂ concentration (Ci) increased with rising atmospheric CO₂ concentrations, whereas the Ci/Ca ratio remained relatively stable throughout the study period. Scenario analysis revealed that, prior to 1980, the long-term trend in iWUE was more consistent with the constant Ci scenario, suggesting relatively strong stomatal regulation. After 1980, iWUE trends became more closely aligned with the constant Ci/Ca scenario, indicating that trees maintained a relatively stable Ci/Ca ratio to balance carbon assimilation and water loss. With increasing drought severity, drought resistance declined in both forest regions; however, substantial spatial differences were observed in drought responses. Under moderate drought conditions, trees in the Haba-River forest area exhibited higher resistance, whereas trees in the Hanaslin forest area showed greater recovery capacity and ecological resilience. Winter temperature, growing-season temperature, late-season temperature, and water availability were identified as key climatic factors influencing variations in the radial growth and iWUE of Larix sibirica. Overall, under the combined influences of rising atmospheric CO₂ concentrations and increasing water limitations, Larix sibirica exhibited adaptive adjustments in carbon–water regulation; however, enhanced iWUE did not fully compensate for the negative effects of drought on radial growth. These findings provide valuable insights into the responses and adaptive strategies of cold-arid forest ecosystems under ongoing climate change and offer scientific support for the conservation and sustainable management of Larix sibiric forests. Full article