Search Results (1,323)

Soil salinization constrains the sustainability of irrigated oasis agriculture in arid regions. Using repeated post-harvest monitoring of 125 fixed cropland sites in Bachu County, southern Xinjiang, from 2018 to 2021, this study investigated the short-term spatiotemporal variability of topsoil total salt content (TSC) and pH. Descriptive statistics, one-way ANOVA with Tukey’s HSD test, Universal Kriging interpolation, class-transition analysis, hotspot recurrence, centroid migration, and principal component analysis were used to characterize temporal variation, spatial structure, and environmental gradient associations. TSC showed a mitigation–rebound sequence, decreasing to 4.88 ± 5.21 g kg⁻¹ in 2020 and increasing to 6.90 ± 5.93 g kg⁻¹ in 2021, whereas pH increased first and then declined. Salinity remained consistently concentrated in downstream cropland, while pH showed weaker and more year-dependent zonal differentiation. Class-transition analysis revealed marked salinity reorganization in 2021, mainly driven by conversion from lower-salinity classes to moderately and severely saline classes. Severe-salinity hotspots were temporally intermittent but spatially recurrent in the downstream zone, whereas high-pH hotspots were short-lived and mainly confined to the upstream zone. PCA further showed that TSC and pH were aligned with different environmental gradient combinations. Overall, the four-year sequence should be interpreted as short-term interannual variability rather than a robust long-term sequence. These results indicate that TSC and pH should not be treated as interchangeable indicators in oasis cropland assessment, and they provide a transferable basis for zone-specific salinity monitoring and management, with priority given to persistent downstream sink areas. Full article

Wind energy is an important form of clean energy, and its rational utilization represents a crucial solution for mitigating the energy crisis and global warming. In this study, wind energy potential and its long-term changes in the South China Sea (SCS) are evaluated using ERA5 100 m wind data from 1944 to 2023, validated against ASCAT observations. High wind speeds and high wind power density (WPD) are concentrated southwest of Taiwan and southeast of Vietnam. Annual wind availability exceeds 6457 h across most regions, reaching up to 8283 h in optimal locations. WPD and capacity factor peak in winter (up to 2.4 × 10⁸ Wh·m⁻² and >50% capacity factor), with the most stable conditions occurring in the southwestern Taiwan Strait, southeast of the Pearl River Delta, and the Beibu Gulf. Empirical orthogonal function analysis reveals that the first mode of winter WPD accounts for 65.7% of the total variance, with a statistically significant increasing trend since 1990. The interannual variation in wind energy resources in the SCS during winter is controlled by the combined effects of sea surface temperature (SST) anomalies in the tropical Pacific and the Arctic Barents Sea. Specifically, in the years with strong wind anomalies in the SCS, mega-La Niña-type SST patterns in the tropical Pacific trigger anomalous cyclonic circulation in the SCS and the eastern Philippine Sea, while warm anomalies in the Arctic Barents Sea surface drive a wave-like structure of “anticyclone–cyclone–anticyclone” from Siberia to South China. The coupling of the two systems jointly promotes the strengthening of the South China Sea monsoon, leading to increased wind speeds and elevated WPD in the northern SCS. These findings provide a scientific basis for wind farm siting and long-term operational planning in the region. Full article

This study assesses the elasticity between integrated media performance and corporate reputation by examining the relationship between Media Output Score (MOS) and RepScore™ in the Portuguese telecommunications sector (Altice/MEO, NOS, and Vodafone) between 2021 and 2023. Adopting a longitudinal observational design, the analysis compares inter-annual variation in communication output with corresponding changes in stakeholder-based reputation. Media performance is operationalized through MOS as a composite indicator of visibility, favorability, readership, targeting, and social amplification, while corporate reputation is measured using third-party RepScore™ data. The findings indicate directional alignment between media output and corporate reputation; however, the magnitude of reputational adjustment appears substantially lower than the amplitude of media volatility. Across heterogeneous crisis contexts, including cybersecurity incidents and governance-related events, reputational scores exhibit incremental and comparatively stable evolution despite pronounced fluctuations in media performance. These results suggest that the relationship between media output and corporate reputation is characterized by constrained responsiveness at the annual level, consistent with a stock–flow interpretation in which communication signals operate as high-variance flows and reputation evolves as a path-dependent stock. By empirically illustrating this asymmetry, the study contributes to media influence research by identifying a structural boundary condition in the translation of media exposure into stakeholder evaluation. The findings further clarify the analytical distinction between output-level communication metrics and outcome-level reputational constructs in digital media environments. Full article

Using a coordinated multi-year monitoring dataset collected during the 2020–2024 partial-opening management period, we examined benthic diatom assemblages across the Sejong, Gongju, and Baekje weirs in the Geum River, Republic of Korea. Seasonal surveys at eight stations were used to evaluate spatiotemporal variation in water quality and benthic diatom community structure under this hydrological management regime. Annual basin-wide averages showed gradual interannual changes in water quality, including declines in total phosphorus, total nitrogen, chlorophyll-a, turbidity, and biochemical oxygen demand after 2021, accompanied by increased dissolved oxygen. Diatom community indices based on relative-abundance data showed corresponding temporal variation, with decreased dominance and increased Shannon diversity, evenness, and taxon richness. Ordination analyses indicated gradual differentiation between the earlier (2020–2021) and later (2022–2024) monitoring groups within the study period, whereas random forest models showed limited explanatory power and were treated as exploratory. Overall, the results support benthic diatoms as sensitive descriptors of ecological change in flow-regulated monsoonal rivers while underscoring the value of long-term monitoring where true pre-intervention biological baselines are unavailable. Full article

The Sichuan Basin is a high-incidence area for China’s drought–flood abrupt alternation (DFAA) events. To reveal the spatiotemporal evolution characteristics and driving factors of drought–flood abrupt alternation (DFAA) compound disasters in the Sichuan Basin, this study identified drought-to-flood (DF) and flood-to-drought (FD) events using the Standardized Precipitation Evapotranspiration Index based on meteorological data and circulation factors from 1963 to 2022. By constructing a standardized drought–flood abrupt alternation magnitude index to classify event grades, combined with methods such as trend analysis, Morlet wavelet and Random Forest, the study explored the trend variation laws, spatial distribution patterns, and core driving factors of DFAA events in the basin. The results showed that on the interannual scale, the upward trend of FD events was more obvious than that of DF events, with a significant increase in the proportion of moderate and severe events; both the frequency and intensity of summer FD events increased significantly, and the intensity of winter FD events also exhibited a marked upward trend. Spatially, DF events occurred frequently in Guang’an and Chongqing, while FD events were concentrated in the western edge of the basin, as well as Yibin and Luzhou. Moderate and severe events were more prominent in the edge areas of the basin. The occurrence of DFAA events was generally jointly driven by the meteorological factors and regulation of large-scale sea surface temperature-circulation factors: the triggering factors of DF events showed a diversified and decentralized characteristic, while FD events were mainly driven by the subtropical high, and tropical sea surface temperature anomalies were the common precursor signal for both types of events. This study provides a scientific basis and technical support for the formulation of disaster prevention and mitigation strategies and the optimal management of water resources for compound extreme meteorological disasters in the Sichuan Basin. Full article

The significant interannual variability in Madden–Julian Oscillation (MJO) intensity remains incompletely understood. Empirical orthogonal function (EOF) analysis reveals that the first three leading EOF modes of the annual mean MJO intensity are significantly correlated with the Quasi-Biennial Oscillation (QBO), Eastern Pacific El Niño-Southern Oscillation (ENSO), and Central Pacific ENSO. Focusing on the distinct EOFs related to three key tropical interannual variabilities, we conduct an investigation into the potential governing processes through which the changes in background mean states impact MJO intensity based on the MJO moisture mode theory. Observations suggest that the accumulation of moist static energy (MSE) during MJO moistening phases and its dissipation during drying phases play a crucial role in regulating MJO amplitude. At the interannual timescale, regions characterized by positive EOF values display positive (negative) MSE tendency anomalies during MJO moistening (drying) phases, leading to amplified MSE accumulation (dissipation) throughout the MJO lifecycle and subsequently facilitating an increase in MJO amplitude. Conversely, regions with negative EOF values exhibit opposing trends. Further analysis reveals that these MSE tendency anomalies are mainly associated with the zonal advection term, which is influenced by interannual changes in the background mean MSE and low-level winds. The spatial pattern of the background mean MSE is strongly linked to sea surface temperature (SST) anomalies, with low-level background winds aligning well with the horizontal gradients of SST anomalies. Full article

Evaluating Net Primary Productivity (NPP) variations driven by climatic variability and mining activities is fundamental for understanding ecological dynamics in high-intensity open-pit mining areas. Focusing on high-intensity open-pit mining areas of Qian’an, China, from 2016 to 2022, by integrating Sentinel-2, ERA-5 Land reanalysis dataset and Dynamic World V1, we employed an improved Carnegie–Ames–Stanford Approach (CASA) framework alongside the Thornthwaite Memorial algorithm to quantify actual NPP (ANPP) and potential NPP (PNPP). Additionally, the Relative Contribution Index (RCI) was utilized to explicitly isolate mining-driven NPP (MNPP) variations. The results revealed a significant downward trajectory in ANPP within the high-intensity open-pit mining area, with a cumulative reduction of 5.3 × 10⁸ gC a⁻¹. This productivity loss exhibited significant spatial heterogeneity, with the most severe degradation concentrated in core mining districts, including Malanzhuang, Caiyuan, Yangdianzi, and Muchangkou. ANPP, MNPP, and PNPP maintained relative stability overall but displayed significant interannual fluctuations during 2019–2022. RCI analysis indicated MNPP dominated ANPP in 62.67% of the study area, with mining impacts intensifying in 62.83% of the region. Driver mechanisms identified precipitation as the dominant climatic factor enhancing ANPP, whereas mining activities constituted the primary driver of ANPP reduction. Mining accounted for 61.33% of ANPP changes, significantly exceeding climatic variability’s 38.67% contribution. In conclusion, these findings provide a scientific foundation for developing ecological carbon sink systems and optimizing ecological restoration strategies. Full article

The critically endangered Kemp’s ridley sea turtle (Lepidochelys kempii) population experienced a catastrophic decline from a peak in 1947 to a low in 1985, followed by exponential growth prior to 2010. However, the Deepwater Horizon (DWH) oil spill caused a demographic setback. Monitoring nesting female straight carapace length (SCL) is crucial for assessing population structure and recovery. We analyzed interannual variation in SCL of nesting females at Rancho Nuevo Sanctuary, Tamaulipas, Mexico, during the 2018–2023 nesting seasons. A total of 191 females were measured, and a comprehensive statistical analysis was performed to validate the use of parametric tests. One-way ANOVA revealed significant differences in mean SCL among years (p < 0.001). The lowest seasonal SCL means were in 2020 (59.01 ± 1.79 cm) and 2022 (60.68 ± 1.47 cm), while the highest SCL means occurred in 2018 (62.77 ± 1.81 cm), 2019 (62.01 ± 1.56 cm), 2021 (62.19 ± 1.47 cm), and 2023 (61.75 ± 2.07 cm). There was no significant linear decline in mean SCL from 2018 to 2023 (p = 0.78). These results suggest short-term interannual variability rather than a consistent shift in body size structure, providing updated baseline information for post-DWH population monitoring and future recruitment assessments. Full article

Dongting Lake, a vital freshwater lake in China with substantial ecological, economic, and social significance, has fractional vegetation coverage (FVC) as a core indicator of regional ecological balance. To characterize the ecosystem’s health and support targeted protection, this study analyzed FVC’s spatio-temporal evolution and associated spatial factors in the Dongting Lake ecological restoration area using 2005–2020 MODIS imagery, integrating the dimidiate pixel model, slope trend analysis, and geographic detector model (noting the latter quantifies spatial explanatory power but not direct ecological causality). Results revealed distinct FVC heterogeneity: 2011 had the poorest vegetation (mean FVC = 0.60), while 2005, 2010, and 2012 showed higher FVC (mean = 0.65); summer exhibited the most vigorous growth due to favorable hydrothermal conditions. Slope was the dominant single factor with the highest spatial explanatory power for FVC (q = 0.50), its distribution strongly associated with soil moisture and erosion. The slope–soil moisture interaction had the strongest joint spatial explanatory power (q = 0.625), reflecting topographic–hydrological synergistic spatial association, implying slope may indirectly modulate vegetation water availability (inferred from spatial correlation, not causality). The slope–DEM interaction (q = 0.534) confirmed combined topographic explanatory effects. Overall, 70.3% of the region saw significant FVC improvement (notably in spring) from 2005 to 2020, with degradation in February, March, and December. Slope emerged as a key factor consistent with interannual and seasonal FVC variations. These findings provide a reliable scientific basis for targeted wetland restoration, emphasizing enhanced vegetation management in summer, autumn, and the growing season. Limitations include: MODIS’s 250 m resolution leading to mixed-pixel effects in fragmented wetlands, limited validation coverage of extreme habitats and single-year verification, and the Geodetector model’s reliance on spatial stratification and factor independence assumptions (deviating from wetland’s continuous factor variation) that preclude causal inference. Full article

In this study, we examined the interannual distribution patterns of the giant jellyfish Nemopilema nomurai and their relationship with marine environmental factors using field survey data collected from the East China Sea from 2020 to 2024. Acoustic surveys and jellyfish-specific trawl sampling were conducted to analyze their vertical distribution characteristics in relation to water temperature, salinity, seawater density, and chlorophyll-a concentrations. The results revealed that N. nomurai were mainly distributed in the mid-to-lower water layers at depths of 40–60 m, particularly in areas with strong stratification between the surface and bottom waters. Temperatures and salinity at these depths were relatively stable, and jellyfish were concentrated within high-density layers (1024.6–1025.0 kg·m⁻³). Correlation analysis revealed significant positive relationships between jellyfish occurrence frequency and salinity and seawater density, whereas no significant relationship was observed with water temperature. The chlorophyll-a concentrations varied between the years but did not directly correspond to the primary habitat depths of jellyfish, although synchronous variations in jellyfish abundance occurred in some years. These results indicate that the vertical distribution of N. nomurai is primarily controlled by physical oceanographic factors rather than by chlorophyll-a concentrations, reflecting an ecological adaptation for efficient energy use. Full article

Understanding how pollinators adjust their behavior to maximize reproductive success in resource-limited desert ecosystems is a fundamental ecological question. In this study, we investigated X. mongolicus using a combination of field behavioral observations, pollen identification, nutritional analysis, and morphometric measurements to systematically examine interannual variations in its flower visitation spectrum, foraging behavior, bee bread composition, and offspring body size. Our findings reveal a striking contrast: although this species exhibits polyphagy in flower visitation, it shows dietary specialization in larval nutrition—over 92% of the pollen in its bee bread originates from just two leguminous species, A. mongolicus and O. bicolor. Foraging duration increased with rising temperature and humidity, and bees adapted to strong winds by flying close to the ground. Compared with 2024, the bee bread in 2025 had lower fresh weight but higher crude protein content, and offspring body size was larger—likely due to more abundant spring rainfall in 2025, which improved the flowering performance of A. mongolicus. Collectively, these results indicate that this bee species copes with resource uncertainty in desert habitats through flexible foraging range and highly specialized food storage, with its reproductive success closely tied to the nutritional supply of key plants and precipitation patterns. This study highlights the role of precipitation timing in shaping the nutritional foundation of plant–pollinator interactions, providing a scientific basis for the conservation and management of desert pollinators. Full article

As one of the most serious challenges in the 21st century, climate change poses a major threat to global grain production, especially in agricultural and populous countries such as China. This study employs the Vegetation Photosynthesis Model (VPM) and Geographically and Temporally Weighted Regression (GTWR) model to systematically quantify and analyze the spatio-temporal heterogeneous responses of three major crop yields (rice, maize, and wheat) to climate change from 2000 to 2018 in China. The results are as follows. (1) During 2000–2018, all climate factors showed significant inter-annual fluctuations and regional variations. Specifically, both mean maximum and minimum temperatures rose by approximately 1 °C overall; total precipitation initially decreased before increasing, with 2011 being the turning point; total sunshine hours fluctuated sharply before stabilizing; mean wind speed increased slowly at first and then more rapidly; and mean relative humidity decreased first and then increased, turning around in 2009. (2) The VPM-based crop yield estimates were well-verified against the statistics from the China Statistical Yearbook, with the coefficient of determination (R²) ranging from 0.77 to 0.84 for the three crops (all p < 0.01), confirming the high reliability of the yield data used in this study. (3) The national mean yields of three crops based on the VPM showed a fluctuating upward trend from 2000 to 2018. Spatially, the yield changes in three crops showed significant regional differences. (4) From 2000 to 2018, crop yields based on the VPM model exhibited distinct responses to climate change: rice yields were mainly positively affected by mean maximum temperature, maize yields were mainly negatively affected by total precipitation, while wheat yields benefited most significantly from mean relative humidity. The Northeast Plain (the major production region for rice and maize) and the Huang-Huai-Hai Plain (the key region for wheat) proved most sensitive to climate change, and the impacts on all three crops intensified over time. The study suggests that in the future, attention should be focused on the adaptive management of major crop production regions under climate change, and multiple approaches such as optimizing the planting structure and layout, improving crop varieties, perfecting the risk management system, and establishing a policy support and guarantee system should be adopted to enhance the climate resilience of the agricultural system. Full article

Background: Health risks from radon exposure depend on long-term radon concentrations. This study quantified interannual variability in residential radon concentrations in Finland and evaluated its implications for exposure assessment and measurement recommendations. Methods: A random sample of 277 dwellings from the national radon registry, representative of Finnish regions, building types, and construction years, was monitored using year-long Makrofol-based track-etch detectors over four consecutive years (2021–2025). Year-to-year variability was characterized using the coefficient of variation (CV). Simulations incorporating the observed CVs, previously established seasonal correction factors, and measurement uncertainty were conducted to determine thresholds for follow-up measurements in relation to reference levels. Results: The coefficient of variation (CV) for normalized annual mean concentrations was 0.16, with 90% of dwellings exhibiting CV ≤ 0.30. Although substantial variation occurred at the individual dwelling level, no statistically significant differences in overall radon levels were observed between years. Simulations showed that applying a 100 Bq/m³ threshold for recommending follow-up measurements results in an approximately 3% false-negative rate relative to the 200 Bq/m³ reference level. Lowering the threshold to 70 Bq/m³ reduces this probability to approximately 1%. Conclusions: These findings are consistent with international studies and provide an empirical basis for recommendations on follow-up radon measurements and for quantifying uncertainties in radon exposure assessment in Finnish dwellings. Full article

Freshwater accumulation is one of the most striking observations in the Beaufort Gyre (BG) region in the Arctic Ocean. A 39-year simulation, using the validated high-resolution, geometrical-fitting, unstructured grid Finite-Volume Community Ocean Model for the Arctic Ocean, aimed to investigate the contributions of coastal currents and their interannual variability to this phenomenon. The model reasonably reproduced the interannual variability of freshwater content (FWC) in the BG region. Analysis revealed the constructive role of Ekman pumping in supplying FWC, while the lateral flux generally acts to remove FWC from the region. The disparity between Ekman pumping and lateral flux drives the interannual variability of total FWC, with accumulation occurring when the downward Ekman FWC flux surpasses the net outflow-induced lateral FWC flux. Since 2007, there has been a significant increase in downward Ekman pumping, accompanied by a rise in net outflow lateral flux, indicating heightened variability of FWC in the BG region. The model results suggested that the coastal flow over the Arctic continental shelf underwent dramatic changes, especially during summer, and these changes were partially due to increased freshwater and sea ice melting. Increased lateral FWC flux during summer has become a competitive source for unprecedented seasonal freshwater accumulation in the BG region. Flow intensification over the North American coast is influenced by increased freshwater runoff, including the Firth, Kobuk, and Mackenzie Rivers. Interannual FWC variation in the Beaufort Sea could be influenced by the changes in slope flow, with the water originating in part from the Barents and Kara Seas. Full article

Drought is a complex natural hazard with severe impacts on ecosystems, agriculture, water resources, and socio-economic stability. Understanding its spatiotemporal evolution is critical for effective drought monitoring and prevention. This study analyzed drought characteristics in Henan province from 1961 to 2023 using the Standardized Precipitation Evapotranspiration Index (SPEI), calculated from daily meteorological data at 111 meteorological stations. Drought was examined at annual and seasonal scales across multiple time scales, including the 1-month time scale (SPEI1), 3-month time scale (SPEI3), and 12-month time scale (SPEI12), and future trends were assessed using Theil–Sen Median and Hurst exponent analyses. Key findings revealed the following: (1) Drought frequency showed a non-significant increasing trend overall, but drought intensity increased significantly, with severe and extreme droughts becoming more frequent. Most areas are projected to continue aridification. (2) Winter recorded the highest frequency and occurrence of droughts, followed by autumn and summer. Except for summer, moderate and severe droughts increased across all seasons. Extreme droughts increased significantly across all seasons, especially in spring and autumn. (3) High annual drought frequency was concentrated in the northwest, north, and east. Spatial patterns varied by drought severity: slight droughts were more common in the north, moderate droughts in the central–east, severe droughts in the west and south, and extreme droughts in the southwest and north. (4) Empirical Orthogonal Function (EOF) analysis revealed three main spatial modes: a uniform regional pattern, a southeast–northwest contrast, and a central–eastern opposition. Shorter time scales provided more detailed spatial patterns, while longer scales better reflected interannual characteristics of drought and flood variations. This study offers valuable insights for improving drought assessment and supporting risk management and policy decisions. Full article