Search Results (206)

The inter-provincial border region in eastern China, encompassing the junction of Jiangsu, Anhui, Shandong, and Henan provinces, serves as a crucial zone that connects the important economic zones of Beijing–Tianjin–Hebei and the Yangtze River Delta. It is of great significance to study the temporal variation characteristics, spatial distribution patterns, and driving factors of PM_2.5 concentrations in this region. Based on the PM_2.5 concentration observation data, ground meteorological data, environmental data, and socio-economic data from 2022 to 2024, this study conducted in-depth and systematic research by using advanced methods, such as spatial autocorrelation analysis and geographical detectors. The research results show that the concentration of PM_2.5 rose from 2022 to 2023, but decreased from 2023 to 2024. From the perspective of seasonal variations, the concentration of PM_2.5 shows a distinct characteristic of being “high in winter and low in summer”. The monthly variation shows a “U”-shaped distribution pattern. In terms of spatial changes, the PM_2.5 concentration in the inter-provincial border region of eastern China (Jiangsu, Anhui, Shandong, Henan) forms a gradient difference of “higher in the west and lower in the east”. The high-concentration agglomeration areas are mainly concentrated in the Henan part of the study region, while the low-concentration agglomeration areas are distributed in the eastern coastal parts of the study region. The analysis of the driving factors of the PM_2.5 concentration based on geographical detectors reveals that the average temperature is the main factor affecting the PM_2.5 concentration. The interaction among the factors contributing to the spatial differentiation of the PM_2.5 concentration is very obvious. Temperature and population density (q = 0.92), temperature and precipitation (q = 0.95), slope and precipitation (q = 0.97), as well as DEM and population density (q = 0.96), are the main combinations of factors that have continuously affected the spatial differentiation of the PM_2.5 concentration for many years. The research results from this study provide a scientific basis and decision support for the prevention, control, and governance of PM_2.5 pollution. Full article

Surface ozone (O₃) is a multifaceted threat that not only deteriorates the environment but also poses risks to human health. Here, we estimated the seamless hourly surface O₃ in China using Extreme Gradient Boosting (XGBoost) with multisource data fusion to investigate spatiotemporal differences in O₃ during multistage COVID-19, and the response of O₃ variation to meteorology and emissions were explored using Shapley Additive Explanations (SHAP) and WRF-Chem. The results indicate that the optimized model demonstrated higher accuracy, with CV-R² of 0.96–0.97 and RMSE of 4.58–5.00 μg/m³. Benefitting from the full coverage of the dataset, the underestimated O₃ was corrected and hotspots of short-term O₃ pollution events were successfully captured. O₃ increased by 16.8% during the lockdown, with high values clustered in the north and west, attributed to the weakened urban NOx titration resulting from reduced emissions. During the control and regulation period, O₃ levels declined year by year. O₃ exhibited significant fluctuations in the Pearl River Delta but remained stable in western China, with both regions demonstrating high sensitivity to meteorological variability. Among these, solar radiation and temperature were the key meteorological factors. The seamless high-resolution O₃ datasets will enable more insightful analyses regarding the spatiotemporal characterization and cause analysis. Full article

In the process of Chinese-style modernisation, the socially and culturally coordinated development of cities in the Yangtze River Economic Belt is important for promoting regional coordinated development, enhancing the balance of public services, and strengthening cultural soft power. This study used quantitative methods, including the construction of an indicator system, spatial correlation analysis, and Zipf’s rank-size rule, on data from 2011 to 2021 to analyse the capacity for coordinated social and cultural development and assessed the spatial distribution characteristics of the Yangtze River Economic Belt. The study found that the overall level of social and cultural coordination among the cities in the Yangtze River Economic Belt steadily improved; however, significant regional disparities still exist, particularly in areas such as social security and cultural integration. Spatially, a “high in the east, low in the west” pattern is observed, with the Yangtze River Delta city cluster leading development, the midstream cluster playing a supportive role, and the Chengdu–Chongqing city cluster showing significant internal disparities. Core cities such as Shanghai, Hangzhou, Wuhan, and Chengdu demonstrated driving effects in areas such as culture, education, and healthcare; however, some peripheral cities remain underdeveloped. This study suggests the need to enhance the development of the Yangtze River’s culture, promote the development of cultural industry clusters, foster the integration of various business models, leverage scientific and educational resources, optimise the cultural consumption market, and achieve the coordinated development of the social and cultural sectors, thereby enabling the Yangtze River Economic Belt to play a greater role in Chinese-style modernisation. Full article

As a typical desert oasis ecosystem in the arid region of Northwest China, the Ejina Delta plays a crucial role in regional ecological security through its vegetation dynamics and landscape pattern changes. Based on Landsat remote sensing images (1990–2020), runoff data, and vegetation landscape surveys, this study investigated the evolutionary patterns and driving mechanisms of vegetation degradation and restoration processes using Normalized Difference Vegetation Index (NDVI), landscape metrics, and Land Use Transition Matrix (LUTM) methods. The following key findings were obtained: (1) Since the implementation of the Ecological Water Diversion Project (EWDP) in the Heihe River Basin (HRB) in 2000, a significant recovery in vegetation coverage has been observed, with an NDVI growth rate of 0.0187/10 yr, which is five times faster than that in the pre-diversion period. The areas of arbor vegetation, shrubland, and grassland increased to 356.8, 689.5, and 2192.6 km², respectively. However, there is a lag of about five years for the recovery of arbor and shrub compared to grass. (2) The implementation of EWDP has effectively reversed the trend of vegetation degradation, transforming the previously herb-dominated fragmented landscape into a more integrated pattern comprising multiple vegetation types. During the degradation period (1990–2005), the landscape exhibited a high degree of fragmentation, with an average number of patches (NP) reaching 45,875. In the subsequent recovery phase (2005–2010), fragmentation was significantly reduced, with the average NP dropping to 30,628. (3) Stronger vegetation growth and higher NDVI values were observed along the riparian zone, with the West River demonstrating greater restoration effectiveness compared to the East River. This study revealed that EWDP serves as the key factor driving vegetation recovery. To enhance oasis stability, future ecological management strategies should optimize spatiotemporal water allocation while considering differential vegetation responses. Full article

The Boronia Ridge palusmont, Walpole, in southern Western Australia, is situated in the most humid part of the State. It was a unique hilltop wetland complex and the only one of its type in the State. On its margins, the area also supports the ancient sedge Reedia spathacea, a Gondwanan relict endemic to humid southern Western Australia and the Walpole region and a plant that was ultimately recognised as being of national significance and protected under Australia’s strongest conservation law, the Environment Protection and Biodiversity Act (1999). However, prior to the geoheritage and biodiversity values of the area being known, in the late 1980s, a pristine scenic area west of Walpole, adjacent to the Walpole River and Walpole Inlet, classified as a Class A national park, was earmarked for urban development, in spite of there being “very little demonstrated requirement for land in Walpole”. This appeared to be as a result of poor land-use planning, since the urbanisation proposed was to be located on the Walpole River delta and wetlands. Urban infrastructures would also impact on adjoining wetlands and the Walpole Inlet System. With new information available in relation to the soils, wetlands, and environmental values of the area, in 1993, community groups and scientists combined, at a public Local Government meeting, to demonstrate that the proposed urban development, referred to as Lot 650, and later Boronia Ridge, with its above-land surface wastewater treatment, was inappropriate, both from an engineering perspective and due to the high conservation values of the area. With the support of the local government of the day and expert scientists who confirmed local concerns, the community engaged in a 7-year conflict with the development proponent, government agencies involved in decision making, and politicians of the day. Ultimately, the use of state-of-the-art science and traditional geomorphic, stratigraphic, hydrological, and geoheritage principles failed to prevent the urbanisation of the area in favour of preserving the whole area as a wetland complex. The following three reasons for this failure are identified: 1. political, rather than science-based decision making, 2. government agencies staffed without the necessary training in biological or earth sciences to make informed decisions, and 3. little attention to environmental concerns due to a bias towards development. Walpole, with its population of 400, moved from a low priority on the wastewater treatment priority list in Western Australia to a high priority on the deep sewerage priority list to accommodate a proposed residential development. Full article

The Vietnamese Mekong Delta (VMD) faces increasing challenges due to upstream hydrological fluctuations and climate change, necessitating optimized water management strategies. Sluice gates play a critical role in regulating water levels, yet their effectiveness under different operational modes remains insufficiently assessed. This study examines water level fluctuations under three sluice gate operation scenarios implemented along the West Sea dike in the Long Xuyen Quadrangle, Kien Giang Province, using the MIKE 11 hydrodynamic model. The model was calibrated and validated using the observed data, yielding high accuracy at key sluice gates, including Kien River and Ba Hon. Three sluice gate management scenarios were tested: (1) the current automatic and partially forced operation, (2) fully automatic gate control, and (3) fully forced hydraulic operation. The simulation results indicate that Scenario 3 maintained water levels above +0.6 m more frequently, ensuring better water availability for irrigation and domestic use, while Scenarios 1 and 2 resulted in lower water levels at certain locations. Additionally, forced operation led to higher gate opening and closing frequencies at key sluices, allowing for more adaptive control over water levels. These findings emphasize the benefits of proactive sluice gate management in improving water regulation and mitigating the water scarcity risks. This study is among the first to provide empirical, scenario-based evidence comparing fully forced, automatic, and mixed sluice gate strategies under varying hydrological conditions in the Long Xuyen Quadrangle. Full article

In Greece, water scarcity is a key factor limiting forest growth, with a strong correlation observed between water availability and tree ring growth in Mediterranean forests. The LIFE-PRIMED project in the Nestos Delta, northeastern Greece, studied tree growth patterns on both riverbanks, noting significant fluctuations towards the east and varying increases towards the west. The drought index revealed a decrease in drought over time, and no clear link between tree growth and drought conditions was found. Severe droughts and dam-induced flooding appear to affect tree growth by altering hydrological patterns. Years of significant decline with notable growth deviations include 1995, 1998, 2000, 2002, 2007, and 2017 in the eastern region, and 2002, 2004, 2007, and 2017 in the western region. Significant droughts in 1990, 1993, and 2001 had limited immediate impact but may have affected growth in subsequent years. Further research is needed to understand the impact of climatic conditions and prolonged floods on tree growth to improve management decisions. Full article

This study analyzed terrestrial water storage (TWS) changes across the Inner Niger Delta (IND) in Mali (West Africa) from April 2002 to September 2022 using Gravity Recovery and Climate Experiment (GRACE), GRACE-Follow-On (GRACE-FO), and Global Land Data Assimilation System (GLDAS) products. TWS changes exhibited strong seasonal patterns (−170 mm to 330 mm) with a high correlation between GRACE/GRACE-FO and GLDAS (r = 0.92, RMSE = 35 mm). The TWS trend was positive (7.3 to 9.5 mm/year). Maximum TWS changes occurred in September, while minimum values were observed between April and May. Wavelet analysis identified dominant seasonal cycles (8–16 months). Finally, we examined the climatic effects on TWS changes along the Niger River, from its source in the humid zones of Guinea to the semi-arid Sahelian zones of the IND in Mali. Precipitation (P) and potential evapotranspiration (PE) influence TWS changes only in the humid regions (r = 0.18–0.26, p-value < 10⁻²). Surface water bodies (SWB) exhibited a significant correlation with TWS in all regions, with r exceeding 0.50 in most cases. Groundwater changes, estimated from GRACE/GRACE-FO and GLDAS, showed strong agreement (r > 0.60, RMSE < 120 mm), with recharge rates increasing in semi-arid and Sahelian regions (r > 0.70, p-value < 10⁻³). This study highlights that precipitation, surface water bodies, and groundwater recharge appear as primary drivers of TWS in different regions: precipitation in the humid forest of Guinea, surface water bodies in the Southern and Northern Guinea Savanna along the Guinea–Mali border, and groundwater recharge in the semi-arid and IND Sahelian regions of central Mali. Full article

River nodes play a crucial role in regulating water and sediment transport within river networks. The SiXianJiao (SXJ) node serves as a key exchange point between the West River (WR) and North River (NR) in the Pearl River Delta (PRD), South China. Understanding the differences in flood diversion dynamics between X-shaped and H-shaped configurations under varying geomorphic conditions is essential for flood management. This study employs the Delft3D-Flow model to investigate the flood diversion mechanisms of these composite river nodes. Results revealed distinct hydrodynamic behaviors: the X-shaped node facilitates greater water exchange due to a shared channel segment, whereas the H-shaped node experiences restricted exchange due to flow resistance in the connecting branch. Both configurations exhibit self-regulating flood diversion processes that significantly reduce flood risks. A critical flow fraction of approximately 75.9% [WR/(WR + NR)] is identified, at which water levels (WLs) at both ends of the SXJ node almost equalize. When the WR flow fraction exceeds this threshold, floodwaters are diverted toward the NR. Below it, the diversion direction reverses. Additionally, flood diversion synchronizes asynchronous flood waves, stabilizing the discharge fraction at Makou (Sanshui), which fluctuates around 75.8% (24.2%) for the X-shaped node and 76.6% (23.4%) for the H-shaped node. These findings enhance our understanding of flood diversion dynamics and provide valuable insights for optimizing flood mitigation strategies and hydraulic infrastructure planning in the PRD and comparable river systems worldwide. Full article

As a key region in China’s “dual carbon” strategy, the Yangtze River Delta region faces the dual challenge of sustaining tourism-driven economic growth and achieving significant emission reductions. Based on panel data of the Yangtze River Delta region from 2000 to 2022, this paper adopts the “bottom-up” method to measure the carbon emissions of tourism transportation. It systematically analyzes its spatiotemporal evolution, decoupling effect, and driving mechanism. The results showed that (1) regional carbon emissions showed a trend of “first rising and then decreasing”. The spatial distribution changed from “high in the east and low in the west” to central agglomeration, and the hot spots of high emissions continued to concentrate in Shanghai and its surrounding cities, reaching a peak in 2019. (2) The decoupling state is mainly weak decoupling. The environmental Kuznets curve verified that carbon emissions and the tourism economy showed an inverted U-shaped relationship, and the decoupling levels of cities were significantly different. (3) Gross Domestic Product and the scale of tourist flow of cultural facilities (grey correlation degree 0.925) are the core positive drivers. In contrast, the travel ratio (contribution value −215.9) and the scale of passenger flow in A-class scenic spots (correlation degree 0.876) are the key inhibiting factors. This paper proposes a three-pronged policy framework of “energy structure optimization—cross-city carbon compensation—cultural and tourism integration” to provide theoretical and empirical support for the low-carbon transformation of urban agglomerations. Full article

The maintenance of critical natural capital stocks lays a basis for achieving sustainable development across the globe. However, the rapid socioeconomic development in the Yangtze River Delta (YRD) region in China has been somewhat in conflict with the sustainability of natural capital, particularly in the domain of land use. This, however, remains largely underexplored across the 41 cities partnering the YRD. The aim of this paper is to bring clarity to the sustainability of land as critical natural capital in YRD cities by using an improved three-dimensional land footprint model, as well as to explore the underlying socioeconomic drivers by using spatial econometric models. We find that land use in most YRD cities has been environmentally unsustainable for a long period of time. Cropland is recognized as major source of land flows, experiencing low depletion of land stocks. By contrast, grazing land is found to have poor appropriation of flows, suffering from severe depletion of stocks. Overall, both appropriation of land flows and depletion of land stocks at aggregate level remain relatively stable but geographically uneven, with rich appropriation of flows in the west and north YRD, and intensive depletion of stocks in the northwest and northeast YRD. In addition, the proportion of primary industry added value to GDP and per capita disposable income are identified as major drivers for the YRD’s environmental unsustainability of land use. Our findings call for renewed policies that pinpoint grazing land, fishing grounds and cropland to enable societal prosperity without accelerating the unsustainability of critical natural capital. Full article

Agriculture in the Indian Sundarbans deltaic region primarily depends on a rice-based monocropping system during the rainy season, with the subsequent season often remaining fallow. To mitigate this issue, a series of experiments using zero tillage and straw mulching (ZTSM) potato cultivation were conducted over eight consecutive years (2017–2024) across various islands in the Sundarbans Delta, West Bengal, aimed to intensify the cropping system and ensure the betterment of the land use pattern using climate-smart agricultural practices. In the initial two years, the experiments concentrated on assessing different potato cultivars and nutrient dosages under zero tillage and paddy straw mulching conditions. During the subsequent years, the focus shifted to field demonstrations under diverse climatic conditions. The research included the application of different macronutrients and growth regulators, in combination with different depths of straw mulching. In the final years of the study, the intervention was dedicated solely to the horizontal expansion of cultivated land. These initiatives aimed to enhance agricultural productivity and sustainable land use in the polders, promoting climate-resilient farming practices. From the sets of experiments, we standardized the sustainable nutrient management strategies and selection of appropriate potato cultivars vis-à-vis depth of straw mulching and, finally, the overall best agronomic practices for the region. The adoption of the ZTSM potato cultivation system demonstrated considerable success, as evidenced by the remarkable increase in the number of farmers employing this sustainable agricultural practice. The number of farmers practicing zero tillage potato cultivation surged from 23 in the initial year to over 1100, covering an area of more than 15 ha, highlighting the effectiveness of the technology. The analysis of the estimated adoption also showed that more than 90% adoption is likely to be achieved within a decade. This potential expansion underscores the benefits of the ZTSM potato cultivation system in improving soil health, conserving water, and reducing labour and costs. As more farmers recognize the advantages of zero tillage potato mulching, this approach is poised to play a pivotal role in sustainable agriculture, enhancing productivity while promoting environmental stewardship. Full article

In the presented work, design conditions for breakwaters were derived from offshore climate reanalysis data (ERA5), which were downscaled to the nearshore by two numerical approaches, i.e., SwanOne and Delft3D, for different average and extreme wave and weather conditions. Model validation was performed using in situ measurements. The advantages and disadvantages of both numerical approaches were investigated. Both models showed sufficient accuracy according to measurements in the field, where SwanOne offers a simple and fast calculation method, while Delft3D provides a more complete representation, not only of waves but also current dynamics. However, it requires a much broader amount of input parameters and more complex boundary conditions. Then, SwanOne was applicable to calculate nearshore wave characteristics based on the input parameters extracted from the statistical analysis of long-term ERA5 data. Based on this process, design wave heights and periods at the nearshore were determined for 10- to 100-year return periods. For breakwater design on the west coast of the Mekong Delta, maximum wave heights in a range of 1.1 m to 1.3 m at a distance of 100 m to 300 m could be determined for a return period of 20 years, corresponding to water depths of 2.33 m and 2.88 m, respectively. Full article

One year of monthly sampling in some lagoons of the Po Delta and a pond in the Comacchio Valleys helped fill a gap in the knowledge of the primary producers of these degraded environments, focusing on the competition between macrophytes and phytoplankton. Key water column and surface sediment parameters showed a strong association with the different primary producers, explaining the main factors influencing the dominance of one group over the other. Phytoplankton, recorded as Chlorophyll-a and Phaeophytin-a, and Chlorophyceae among the macrophytes, dominated in conditions of high water turbidity and elevated nutrient concentrations. In contrast, macrophytes, particularly Rhodophyceae, their abundance, total biomass, and number of taxa. prevailed in clear, oxygenated waters. Under optimal conditions, sensitive macroalgae and aquatic angiosperms were also present. Additionally, the current list of macroalgal taxa has been updated, highlighting the dominance of some nonindigenous species (NIS) that had not been recorded before the 2000s. Specifically, Gracilaria vermiculophylla and Ulva australis, native to the North West Pacific (Japan, Korea, China, and Vietnam) and to South Australia, as well as the Indo-West Pacific (India, South Africa, Japan, and Korea), respectively, are now the most frequent and abundant taxa in these lagoons. Full article

The development of the effective source rocks of the Eocene and Oligocene directly determines the oil and gas exploration potential in the northern Yinggehai Basin in China. Based on the analogy with the Hanoi Depression in Vietnam and the Yacheng District in the Qiongdongnan Basin and the comprehensive analysis of self-geological conditions, the development conditions of Eocene and Oligocene source rocks in the northern Yinggehai Basin are examined, focusing on tectonic evolution, sedimentary facies, and the paleoenvironment. Finally, the sedimentary models for the effective source rocks are established. The tectonic activity controlled the formation of the sedimentary deep depression and the migration of the sedimentary trough center, which migrated from east to west and then south from the Eocene to the Oligocene, leading to the sedimentary migration of good muddy source rocks. There are multiple sedimentary facies in favor of source rocks, including lacustrine facies, shallow marine facies, and delta plain swamps. The paleoenvironment indicates that the paleoclimate transitioned from warm and humid to cold and arid, the redox conditions evolved from semi-reducing to oxic, and paleoproductivity increased from the early to late Oligocene. Therefore, the early Oligocene was more conducive to the enrichment of organic matter. It is speculated that the warm and humid paleoclimate, reducing environment, and high paleoproductivity of the Eocene promoted the sedimentation and preservation of more organic matter. The above studies show that the northern Yinggehai Basin, especially the sedimentary period of the Eocene and Oligocene, has favorable geological conditions for the development of effective source rocks. The sedimentary models for Eocene lacustrine mudstones and Oligocene marine mudstones and marine–continental transitional coal-measure source rocks were established. These studies make up for the serious deficiency of previous research and mean that there is great exploration potential for oil and gas in the northern Yinggehai Basin in China. Full article