Beijing-Tianjin-Hebei Research Articles

Impacts of compound extreme weather events on summer ozone in the Beijing-Tianjin-Hebei region

The Beijing-Tianjin-Hebei (BTH) region faces severe summer ozone (O3) pollution. In this study, we conducted a comprehensive analysis of O3 concentration variations during compound extreme (CE) weather events that occur simultaneously with atmospheric stagnation and heat wave during the summer period from 2015 to 2021. Our results showed that during CE events, the rate of O3 exceedance was nearly three times higher compared to non-CE days. O3 concentrations remained relatively stable during CE events lasting five days or less in regions other than Beijing, but when CE events extended beyond five days, both O3 concentration and the exceedance rate increased rapidly. Under CE conditions, daily O3 pollution persisted for a longer duration with 70.0% of daily O3 peaks surpassing 200 μg m−3, especially between 7 a.m. and 12 p.m., the time when CE events had a significant impact on O3 concentration characterized by a rapid rise in O3 concentration. The movement of the western Pacific subtropical high towards the east and its northward shift may contribute to the occurrence of favorable conditions for CE events in the BTH region, but meteorologically these results can be attributed to anticyclonic and high-pressure system anomalies during CE events in the BTH region, which are characterized by low total cloud cover, high temperature, low relative humidity, and high radiation. Positive anomalies in vertical velocity further contribute to favorable conditions for photochemical O3 formation, accumulation, and persistent O3 exceedances.

Evaluation of Site Suitability for Photovoltaic Power Plants in the Beijing–Tianjin–Hebei Region of China Using a Combined Weighting Method

As the construction of photovoltaic power plants continues to expand, investors have placed great importance on the suitability assessment of site selection. In this study, we have developed a multi-level evaluation system and proposed an AHP–XGBoost–GIS comprehensive evaluation model for assessing site suitability in the Beijing–Tianjin–Hebei region. The findings revealed that approximately 48,800 km2 (21.59% of the total area) constituted a suitable area in this region, surpassing previous research results. Generally suitable areas accounted for the largest proportion at 35.89%. Suitable areas in Beijing and Tianjin were relatively limited, with most of them concentrated in Baoding City, Zhangjiakou City, and Chengde City on the northwest side of the “Yanshan-Taihang Mountains”, where there are ample wastelands with gentle slopes conducive to constructing photovoltaic power plants southeast of the “Yanshan-Taihang Mountains”, and solar radiation conditions were better. However, ecological and economic factors restricted suitable areas resulting in smaller coverage including cities such as Handan, Xingtai, Qinhuangdao, and Tangshan, among others. This study successfully overcame limitations associated with traditional subjective evaluation methods by providing decision support for regional energy allocation planning and spatial planning efforts, as well as environmental protection endeavors.

Spatiotemporal Variability and Impact Factors of Domestic Water Prices in China

Given China’s status as one of the most water-scarce countries globally, its rapid development of urbanization and sustained economic growth have led to increasing pressure on the urban water supply. Water pricing is also receiving increasing attention as an important tool for water resource management. This study analyzes the spatial and temporal characteristics of domestic water prices in China and their drivers. To this end, domestic water price data from 285 cities in China were collected. Spatial statistical analysis and geodetector were used to examine the spatial distribution and temporal patterns of domestic water prices from 2007 to 2020, as well as to identify the primary factors influencing these prices. The following results are noted: (1) The national average domestic water price has increased from 2 RMB/m3 to 3.12 RMB/m3, where the northeast and eastern regions have higher prices than the national average, while the central and western regions have lower prices. (2) The spatial distribution of urban domestic water prices presents clear differences characteristic of north–south and spatial agglomeration effects; the high-value area of domestic water prices is mainly concentrated in Beijing–Tianjin–Hebei. (3) On a national and regional scale, the price of domestic water is closely related to economic development, water resources, and resident’s income level. Furthermore, this study revealed that the interaction between pairwise factors played a more significant role in influencing domestic water prices compared with the individual impact of each factor. This finding contributes to a deeper understanding of the spatiotemporal heterogeneity in domestic water pricing and offers valuable insights and guidance for water pricing reform in China.

High-resolution mapping of transport CO2 emission in Beijing–Tianjin–Hebei region: Spatial-temporal characteristics and decoupling effects

Numerous studies estimating transport CO2 emissions in developing countries were on the large scales and few provided high-resolution mapping of transport CO2 emissions from different transport modes according to their respective distribution and diffusion patterns. This study proposed a hybrid method for high-resolution mapping of transport CO2 emissions in metropolitan regions, and applied it to the Beijing–Tianjin–Hebei (BTH) region of China during 2000-2019. The results indicate that: (1) The transport CO2 emissions in the BTH region increased rapidly, of which road transport carbon emissions accounting for approximately 80%, air transport carbon emissions accounting for nearly 20%, railway and water transport accounted for a relatively small proportion. (2) For the transport CO2 emission structure from 2000 to 2019, road transport was still the main source, but its proportion has decreased since recent years, which air transport became the second largest source of emissions and had greater impact on Beijing and Tianjin. (3) The transport carbon emission hot spots were mainly located in Beijing and kept shrinking, while the cold spots were mainly located in the southern part of Hebei Province and kept expanding. (4) The decoupling relationship between county-level transport carbon emissions and economic growth changed from weak decoupling to expansive negative decoupling, showing a non-ideal development in the BTH region. Overall, this study revealed the spatiotemporal characteristics of transport CO2 emissions in the BTH region, based on which specific carbon reduction strategies could be promoted to facilitate sustainable low-carbon transport development in metropolitan regions in developing countries.

How to recognize and characterize land use-based carbon emissions within city networks in the Beijing-Tianjin-Hebei region of China

Human-induced land modification is a significant contributor to carbon emissions. To facilitate the collective reduction of emissions within city clusters and promote eco-friendly urban development, this paper developed a research framework for analyzing carbon emissions. An empirical study was conducted within the Beijing-Tianjin-Hebei (BTH) region of China, focusing on the spatio-temporal patterns of carbon emissions and network features. The results showed that: (1) Carbon emissions among cities in the BTH region displayed significant variation from 2005 to 2020, with an increasing gap in carbon deficit. (2) Inter-city carbon emission correlation showed a declining trend, accompanied by pronounced spatial spillover effects in the region. (3) The network exhibited a bicentric pattern, centered around BJ and TJ, and the network correlations were more likely to occur between nearby developed cities, with poor regional synergistic emission reduction capacity. The implications of this study are valuable for promoting the establishment of an economic system that fosters green, low-carbon, and circular development. Furthermore, the findings contribute to the effective pursuit of carbon reduction and mitigation of climate change in China.

Model Simulations and Predictions of Hydroxymethanesulfonate (HMS) in the Beijing-Tianjin-Hebei Region, China: Roles of Aqueous Aerosols and Atmospheric Acidity.

Hydroxymethanesulfonate (HMS) has been found to be an abundant organosulfur aerosol compound in the Beijing-Tianjin-Hebei (BTH) region with a measured maximum daily mean concentration of up to 10 μg per cubic meter in winter. However, the production medium of HMS in aerosols is controversial, and it is unknown whether chemical transport models are able to capture the variations of HMS during individual haze events. In this work, we modify the parametrization of HMS chemistry in the nested-grid GEOS-Chem chemical transport model, whose simulations provide a good account of the field measurements during winter haze episodes. We find the contribution of the aqueous aerosol pathway to total HMS is about 36% in winter in Beijing, due primarily to the enhancement effect of the ionic strength on the rate constants of the reaction between dissolved formaldehyde and sulfite. Our simulations suggest that the HMS-to-inorganic sulfate ratio will increase from the baseline of 7% to 13% in the near future, given the ambitious clean air and climate mitigation policies for the BTH region. The more rapid reductions in emissions of SO2 and NOx compared to NH3 alter the atmospheric acidity, which is a critical factor leading to the rising importance of HMS in particulate sulfur species.

High-resolution estimation of industrial water use in Beijing-Tianjin-Hebei based on multi-source data

Understanding changes in industrial water use at finer spatial scales is critical for regional water allocation and sustainability. This study employs a top-down method based on multi-source data to estimate the industrial water use at 1 km × 1 km resolution in the Beijing-Tianjin-Hebei (BTH) region during 2000–2019. Statistical data from municipalities and prefectures are used to assess the accuracy of simulated industrial water use. During the validation period, all accuracy validation indices (R, NSE, |RE|, RMSE) have achieved good results, indicating that the method is credible. In addition, industrial water use at the county level in BTH has a strong spatial correlation with 99% confidence. Spatiotemporal change pattern mainly depends on the industrial scale and technical level of prefecture-level cities, and the economic environment will also contribute to changes in the annual industrial water use in BTH. The method provides a reference for high-resolution estimation of industrial water use and can also be applied to regional water management and allocation.

A high-resolution (0.1° × 0.1°) emission inventory for the catering industry based on VOCs and PM2.5 emission characteristics of Chinese multi-cuisines

Catering enterprises gather in densely populated areas, whose pollutant emission has an important impact on human health and environmental quality. This study investigated detailed information of 5456 catering enterprises in a typical city, and analyzed PM2.5 and VOCs components of 15 catering cuisines and different scales. Based on the measured emission factors, the basic information of nationwide catering enterprises and the population density, this study established the national catering pollutant emission inventory with the spatial resolution of 0.1° × 0.1°. As the results showed, alkanes, alkenes and oxygenated volatile organic compounds (OVOCs) were the main components in VOCs of most catering cuisines, accounting for 36.6%–96.7%, while organic carbon (OC) was the dominant component in PM2.5, accounting for 55.4%–68.6%. The same cuisine of different scales also presented certain differences in emission characteristics. The total emissions of the ozone formation potential (OFP) and secondary organic aerosols formation potential (SOAFP) were 1737.8 kt and 76.4 kt, respectively, with alkanes and OVOCs being the main contributors, contributing 27.5% and 22.3%, respectively. Acetaldehyde, ethylene, propylene and the other top ten VOC species contribute 81.0% of the total OFP emissions, while toluene contributed much more to total SOAFP emissions than other VOC species, contributing 35.9%. The air pollutant emissions showed the highest correlation with the population, and the regions with prominent emissions were mainly concentrated in the Beijing-Tianjin-Hebei (BTH) region and coastal cities. This study is a systematic understanding of air pollutant emission characteristics of the catering industry in China, which has important supporting value for pollutant emission reduction planning in the catering industry.

Evaluation of the Spatiotemporal Change of Ecological Quality under the Context of Urban Expansion—A Case Study of Typical Urban Agglomerations in China

As a significant manifestation of human activities influencing natural environment, rapid urbanization has enhanced economic prosperity while simultaneously posing threats to ecological quality. Beijing–Tianjin–Hebei (BTH), the core region of the Yangtze River Delta (CYRD), and the Pearl River Delta (PRD) stand as three major economic centers characterized by the highest level of urbanization in China, encompassing areas of heightened ecological sensitivity. Nevertheless, the ecological quality at the scale of urban agglomerations remains ambiguous, with many studies failing to develop a comprehensive and effective method for comparing diverse urban agglomerations. Consequently, this study integrates multi-source remote sensing data, including information on land cover and other socio-economic parameters, to construct the Ecological Quality Index (EQI) based on the “Function–Interaction–Pressure–Stability” (FIPS) framework. Through a stratified determination of indicator weights grounded in both objective importance and empirical knowledge, we mapped the spatiotemporal changes of EQI and analyzed the impact of urbanization on ecological quality in three urban agglomerations from 2001 to 2020. We determined the following: (1) The calculated EQI can further capture the nuanced details with better performance at both underlining the discrepancy of highs and lows of EQI and describing the spatial detail of urban agglomerations’ characteristics. (2) Substantial disparities in EQI and its changes are evident across different urban agglomerations. Notably, only the average EQI improves in PRD, while ecological degradation is prominent in specific regions, such as the southeastern plains of BTH area, along the Yangtze River, and around Shanghai in CYRD and central PRD. The CYRD exhibits the largest affected area. (3) Urbanization predominantly influences ecological quality through land cover transitions. In expansion areas, ecological deterioration is significantly more pronounced, constituting approximately 90% of the total area. (4) Despite significant urbanization, city-level analysis in CYRD reveals a better coordination between urban expansion and ecological protection, with a lower intensity of ecological degradation compared to urban expansion rates. Conversely, some cities in the BTH, despite modest urban expansion, exhibit substantial declines in ecological quality, highlighting the need for targeted policy interventions. In conclusion, this study elucidates the intricate relationship between urbanization and ecological quality, offering valuable insights for the development of targeted protection strategies and sustainable urban planning.

Retrieval of Aerosol Optical Depth and FMF over East Asia from Directional Intensity and Polarization Measurements of PARASOL

The advantages of performing aerosol retrieval with multi-angle, multi-spectral photopolarimetric measurements over intensity-only measurements come from this technique’s sensitivity to aerosols’ microphysical properties, such as their particle size, shape, and complex refraction index. In this study, an extended LUT (Look Up Table) algorithm inherited from a previous work based on the assumption of surface reflectance spectral shape invariance is proposed and applied to PARASOL (Polarization and Anisotropy of Reflectances for Atmospheric Science coupled with Observations from a Lidar) measurements to retrieve aerosols’ optical properties including aerosol optical depth (AOD) and aerosol fine-mode fraction (FMF). Case studies conducted over East China for different aerosol scenes are investigated. A comparison between the retrieved AOD regional distribution and the corresponding MODIS (Moderate-resolution Imaging Spectroradiometer) C6 AOD products shows similar spatial distributions in the Jing-Jin-Ji (Beijing–Tianjin–Hebei, China’s mega city cluster) region. The PARASOL AOD retrievals were compared against the AOD measurements of seven AERONET (Aerosol Robotic Network) stations in China to evaluate the performance of the retrieval algorithm. In the fine-particle-dominated regions, lower RMSEs were found at Beijing and Hefei urban stations (0.16 and 0.18, respectively) compared to those at other fine-particle-dominated AERONET stations, which can be attributed to the assumption of surface reflectance spectral shape invariance that has significant advantages in separating the contribution of surface and aerosol scattering in urban areas. For the FMF validation, an RMSE of 0.23, a correlation of 0.57, and a bias of −0.01 were found. These results show that the algorithm performs reasonably in distinguishing the contribution of fine and coarse particles.

Decisive role of atmospheric circulation in the troposphere on ozone pollution in the Beijing-Tianjin-Hebei region

Using ozone observations and the ERA5 reanalysis, general circulation conditions between high and low ozone periods in the Beijing-Tianjin-Hebei (BTH) region in June are compared. The atmospheric circulation pattern is contrastingly different in midlatitudes between high and low ozone concentration periods. During high ozone periods in the BTH region, the East Asia–Pacific jet center shifts further eastward in the upper troposphere. Additionally, positive geopotential height anomalies develop at 500 hPa over the BTH region, accompanied by anomalously warm near surface conditions. In contrast, during low ozone periods in BTH, a similar circulation pattern is observed but with the sign reversed. During high (low) ozone periods, the temperature in the lower troposphere usually rises (reduces), solar ultraviolet radiation increases (decreases), and cloud cover, precipitation, and humidity decreases (increases). Moreover, during high (low) ozone periods in BTH, warm (cold) anomalies develop in the low troposphere, extending from the surface upward. This meteorological condition is (not) conducive to photochemical reactions in the near surface layer. The tropopause over the BTH region is anomalously higher (lower) during high (low) ozone periods, and the upper tropospheric ozone is ∼20% less (∼17.5% higher) than the average. Ozone from the upper levels might not consistently contribute to an increase (decrease) in the near surface ozone concentration in BTH, while negative (positive) ozone concentration anomalies prevail in upper levels. Existing evidence suggests that the frontal zone in the troposphere offsets the dynamic contribution of stratospheric transport to changes in ozone content in BTH.

Associations between Land-Use Patterns and Cardiovascular Disease Mortality in the Beijing—Tianjin–Hebei Megacity Region

Megacity regions where human activities are intensive are key areas for CVD prevention and control in China. Optimizing land-use patterns has been widely recognized as an important public health intervention. Ecological space, agricultural space, and construction space are three basic management objects in China’s new land-use management system. Given that most existing studies focused on a single type of land use, this study treats them as a whole and not only explores the impact of each type, but also systematically investigates the effects of the interactions between any two types of land use and the whole land-use pattern. Specifically, this study first constructs a hierarchical index system, then uses spatial error models (SEM) to explore the global associations between each index and age-standardized CVD mortality rates (ASMRs) and uses the multiple geographical weighted regression model (MGWR) to explore the spatial heterogeneity of factor effects. The possible association between land-use patterns and CVD mortality is then explored, and recommendations for policy formulation are provided. The analysis results show that the overall pattern of moderately decentralized and organically combined land use can control CVD mortality to a certain extent, but the specific influence mechanisms show significant differences according to different land-use types, relationships, and location conditions. First, in terms of single-type land-use distribution, the concentration of ecological space has positive health benefits, while a too high concentration of agricultural space has negative effects. Second, the combination of different types of land use has a significant association with CVD, in which the mixed layout of ecological and agricultural space helps to suppress CVD, while ecological and construction space need to be appropriately regularized and should not be too interspersed. Third, the same index may have different effects in different regions, suggesting that policy makers need to tailor their policies to local conditions.

Higher UHI Intensity, Higher Urban Temperature? A Synthetical Analysis of Urban Heat Environment in Urban Megaregion

Urban heat islands (UHIs) aggravate urban heat stress and, therefore, exacerbate heat-related morbidity and mortality as global warming continues. Numerous studies used surface urban heat island intensity (SUHII) to quantify the change in the UHI effect and its drivers for heat mitigation. However, whether the variations in SUHII among cities can demonstrate the physical difference and fluctuation of the urban thermal environment is poorly understood. Here, we present a comparison study on the temporal trends of SUHII and LST in urban and nonurban areas in 13 cities of the Beijing–Tianjin–Hebei (BTH) megaregion in China and further identify different types of changes in SUHII based on the temporal trends of land surface temperature (LST) in urban and nonurban areas from 2000 to 2020. We also measured the effect of the changes in four socioecological factors (i.e., population density, vegetation greenness (EVI), GDP, and built-up area) on the trends of SUHII to understand the dynamic interaction between the UHI effect and socioecological development. We found the following. (1) Nine out of thirteen cities showed a significant increasing trend in SUHII, indicating that the SUHI effects have been intensified in most of the cities in the BTH megaregion. (2) The spatial pattern of summer mean SUHII and LST in urban areas varied greatly. Among the 13 cities, Beijing had the highest mean SUHII, but Handan had the highest urban temperature, which suggests that a city with stronger SUHII does not necessarily have a higher urban temperature or hazardous urban thermal environment. (3) Four types of changes in SUHII were identified in the 13 cities, which resulted from different temporal trends of LST in urban areas and nonurban areas. In particular, one type of increasing trend of SUHII in seven cities resulted from a greater warming trend (increasing LST) in urban than nonurban areas (SUHII↑1), and another type of increasing trend of SUHII in Beijing and Chengde was attributed to the warming trends (increasing LST) in urban areas and the cooling trends (decreasing LST) in nonurban areas (SUHII↑2). Meanwhile, the third type of increasing trend of SUHII in Zhangjiakou was due to a greater cooling (decreasing LST) trend in nonurban areas than in urban areas (SUHII↑3). In contrast, three cities with a decreasing trend of SUHII were caused by the increase in LST in urban and nonurban areas, but the warming trend in nonurban areas was greater than in urban areas (SUHII↓1). (4) Among the relationship between the trend of SUHII (TrendSUHII) and the changes in socioecological factors (Trendpopulation density, TrendGDP per captica, TrendEVI, and Trendbuild-up area), a significantly positive correlation between TrendSUHII and TrendEVI indicated that the change in SUHII was significantly related to an increased rate of EVI. This is mainly because increased vegetation in nonurban areas would result in lower temperatures in nonurban areas.

Measurement and Influencing Factors of Willingness to Accept Payment for Ecosystem Service Provision: A Case Study of a Leading Forest Farm in China

The Saihanba Forest Farm, a leading planted forest farm, is one of the essential ecosystem service providers for the Beijing–Tianjin–Hebei region in China. Its efforts in afforestation and landscape restoration have been recognized with the award of the Champions of the Earth from the United Nations. However, the Saihanba Forest Farm is facing the challenges of less income resulting from less commercial cutting since it has to prioritize providing ecosystem services such as water conservation, wind prevention, sand fixation, and so on, instead of timber. It is crucial to understand providers’ attitudes toward ecosystem service provision and willingness to accept payment, as it might affect the quantity and quality of ecosystem service provision in the future. In this study, the contingent valuation method was applied to measure the willingness to accept payment for the economic losses incurred due to providing ecosystem services by cutting less wood. A questionnaire survey was conducted among the staff of the Saihanba Forest Farm. A double-hurdle regression model was used to analyze the influencing factors of the willingness to accept payment, with the validation via a Tobit model. The results showed that the Saihanba Forest Farm was willing to accept a payment of CNY 9800.84 (USD 1407.24) per hectare per year for providing ecosystem services to enhance social welfare. The factors, including basic sociodemographic characteristics, attitudes toward conservation activities, and awareness on the concept of payment for ecosystem services, significantly influenced their willingness to accept payment.

Spatiotemporal Variation in the Meteorological Drought Comprehensive Index in the Beijing–Tianjin–Hebei Region during 1961–2023

It is crucial to investigate the characteristics of meteorological drought in the Beijing–Tianjin–Hebei (BTH) region to improve the accuracy of agriculture and water resource monitoring and management. In this study, using instrumental observation data from 85 meteorological stations in the BTH region during 1961–2023 derived from the National Meteorological Information Center, we first calculated the meteorological drought comprehensive index (MCI) and analyzed the spatiotemporal characteristics of the MCI. In the BTH region, the MCI intensity from May to June was the most severe in the intraseasonal variation. The trend of the decreasing drought intensity in May–June has occurred for the past 60 years. The southern region in the BTH region was more likely to experience droughts. Next, the spatial patterns of the top two EOF modes of the May–June MCI were depicted. The primary spatial pattern of the BTH, which was characterized by consistent changes in the MCI throughout the entire BTH region, could be represented by the first mode’s R2 of 69.01%. Then, we compared the spatial pattern of the MCI intensity under different return periods. Using the May–June MCI of 1961–2023, the drought intensity gradually increased from northwest to southeast for the 10-, 20-, and 50-year return periods. However, the drought intensity decreased and then increased from northwest to southeast based on the 1991–2023 MCI. Notably, a 20-year return period of severe drought affected Beijing and northern Hebei in 2023. Finally, we discussed the linkages of drought in the BTH region and atmospheric circulation/sea surface temperature (SST) anomalies, which were calculated using the Pearson correlation coefficient and wavelet coherence. We suggest that the MCI variations in the BTH region may be related to the SST anomalies of the Indian Ocean in 1961–1990 and the Pacific Ocean in 1991–2023, respectively. The abovementioned studies have enlightened us to focus on predicting the Pacific SST for drought, which will facilitate agricultural production and water resource management in the BTH region.

Climate Change Impacts on Agricultural and Industrial Water Demands in the Beijing–Tianjin–Hebei Region Using Statistical Downscaling Model (SDSM)

As a politically and culturally important city cluster, the Beijing–Tianjin–Hebei (BTH) region is the most prominent area in China where the imbalance between the supply and demand of water resources restricts the sustainable and healthy development of the regional social economy. In the context of global warming, research into water demand prediction that takes climate change into consideration would be more in line with the strategic goal of the low-carbon sustainable development of future cities. At the same time, the prediction of agricultural water demands against a background of climate change is urgently needed, while industrial water consumption is weakly correlated with climate change, an investigation of the statistical relationship between the two is needed. Thus, in this paper, future climate data from the BTH region under the scenarios RCP2.6, RCP4.5 and RCP8.5 were generated using a statistical downscaling model, and then coupled with agricultural and industrial water demand prediction models to simulate and analyze the impact of climate change on the agricultural and industrial water demands, respectively. The results show that during the forecast period (2020–2035), the reference crop evapotranspiration (ET0) growth rates in the Beijing, Tianjin and Hebei areas under the RCP2.6 scenario are 1.438 mm·a−1, 1.393 mm·a−1 and 2.059 mm·a−1, respectively. Under the RCP4.5 scenario, they are 2.252 mm·a−1, 2.310 mm·a−1 and 2.827 mm·a−1, respectively. Under the RCP8.5 scenario, they are 3.123 mm·a−1, 2.310 mm·a−1 and 2.141 mm·a−1, respectively. Furthermore, under each climate scenario, the increase in evapotranspiration in the Hebei area is the largest, followed by that in the Tianjin area, and that in the Beijing area is the smallest. For water consumption per CNY 10,000 of industrial added value during the forecast period, under the three different climate scenarios, a downward trend is seen in the Beijing area, with rates of 0.158, 0.153 and 0.110, respectively, but in the Tianjin area, there is an upward trend, with an upward tendency in rates of 0.170, 0.087 and 0.071, and an upward trend in the Hebei area, with an upward tendency in rates of 0.254, 0.071 and 0.036, respectively. This study will help the BTH region to rationally allocate agricultural and industrial water against the background of future climate change, and strengthen the coordination and cooperation between the different regions to promote the healthy and sustainable development of the cities.

Study on the Spatial Distribution Characteristics and Influencing Factors in the Reuse of National Industrial Heritage Sites in China

Industrial heritage is a valuable spatial resource for urban stock updates, and its preservation and reuse play an important role in the transmission of urban history and culture. Typological analysis, descriptive statistical analysis, relevant spatial analysis using ArcGIS 10.8, and geographic probes were employed to explore the spatial distribution characteristics and influencing factors regarding the current status of the reuse of 196 heritage sites selected from five batches of China’s National Industrial Heritage (NIH) lists. The results reveal the following: (1) The spatial distribution of China’s NIH sites is uneven and cohesive, forming a dense circle with the Yangtze River Delta region and the Beijing–Tianjin–Hebei region at its core. (2) Three-fourths of the NIH sites have entered the reuse stage, and high-density and relatively high-density clusters have formed in the eastern and central regions. (3) The conservation and reuse directions of China’s NIH sites are mainly divided into publicization and marketization. (4) The spatial distribution differentiation of the reuse of NIH sites is not due to a single cause but, rather, a combination of various contributing factors. Natural geographic and socio-economic factors exert varying degrees of influence on the spatial distribution of reused heritage sites, with tourism resources and government support playing primary roles in shaping this distribution. These findings establish a fundamental database of China’s NIH sites and provide guidance for the current conservation and reuse of industrial heritage.

The Spatial Protection and Governance of Territories Based on the Ecological Product Supply: A Case Study in Beijing–Tianjin–Hebei, China

Territory space is an ecological resource carrier and place for human development. Human activities and ecological systems are the basis of ecological product supply. Promoting territories’ spatial protection and governance by improving the supply of ecological products is very important. In this study, we established an ecological product supply capacity evaluation index system involving three types of ecological products, i.e., ecological environmental products, ecological material products, and ecological cultural products. For the case of the Beijing–Tianjin–Hebei region, we comprehensively used principal component analysis, the equivalent factor method, and the entropy method to evaluate the supply capacity of ecological products from 2011 to 2021. Then, we analyzed the spatio-temporal pattern, combining the natural breakpoint and quantile classification methods, and analyzed the obstacle factors using the obstacle degree model of ecological supply. The results show that the supply capacity of different ecological products in each city are closely related to their ecological resource endowment. The supply capacity of ecological products exhibited an upward trend, with the highest ecological environmental product supply being relatively smaller than the ecological material product supply, while the largest growth rate was for ecological cultural product supply. The supply capacity of different ecological products varied across cities over time and displayed noticeable spatial differentiation. The main obstacle factors included eco-land, eco-tourism, eco-leisure, park green space, and fishery products, although there were variations among cities. Finally, based on the level, spatial-temporal pattern, and obstacle factors of ecological product supply, we proposed strategies for territory spatial protection and governance from the perspectives of the integrated protection of elements, structural regulation, and systematic governance. The results reflected the ecological functional heterogeneity of the territory space, which can provide spatial planning guidance for sustainable development.

Short- and medium-chain chlorinated paraffins in sediment from the Haihe River Basin: Sources, distributions, and ecological risk assessment

Chlorinated paraffins (CPs) can accumulate in sediment and pose risks to ecological systems and human health. The Haihe River Basin is one of the seven main river basins in China and is mainly in the Beijing–Tianjin–Hebei region, which is densely populated and very urbanized. There is therefore a high probability of CP pollution in the Haihe River Basin. However, CP pollution and the environmental risks posed by CPs in the Haihe River are not well understood. In this study, the concentrations of short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) in sediment from six rivers in the Haihe River Basin system were determined using two-dimensional gas chromatography electron-capture negative ionization mass spectrometry. The total SCCP and MCCP concentrations in the sediment samples ranged from 131.83 to 1767.71 and from 89.72 to 1442.82 ng/g dry weight, respectively. The total organic carbon content did not significantly correlate with the CP concentrations. The dominant SCCP congener groups were C10Cl6–7 and the dominant MCCP congener groups were C14Cl7–8. Significant relationships (R = 0.700, p < 0.05) were found between the SCCP and MCCP concentrations, indicating that SCCPs and MCCPs may have similar sources. Hierarchical cluster analysis and principal component analysis indicated that sediment in the study area was contaminated with CPs through the use of the CP-42 and CP-52 commercial products in industrial processes and human activities. The ecological risks posed by CPs were assessed and SCCPs were found to pose high risks in the Yongding New River but moderate risks in the other rivers. MCCPs were found to pose minimal risks to the aquatic environment at most of the sampling points.

Aerosol effects on the three-dimensional structure of organized precipitation systems over Beijing-Tianjin-Hebei region in summer

Aerosol effects on organized precipitation systems (PSs) over Beijing-Tianjin-Hebei (BTH) region are investigated using 6 years of Global Precipitation Measurement (GPM) observations. An auto-clustering algorithm was used to identify local-scale PSs under different aerosol loading conditions and to quantify their three-dimensional structure properties. The general characteristics of PSs show a non-monotonic trend with increasing aerosol optical depth (AOD). The near surface rain rate, the maximum radar reflectivity, the horizontal precipitation area and the vertical extension of PSs decrease with increasing AOD when aerosol loading is low. However, for higher aerosol loadings, the precipitation area first increases and then decreases with increasing AOD. By constraining the variations of meteorology conditions and by calculating the partial correlations, aerosol effects rather than meteorology effects are most likely the major causes for the observed changes of PSs. One possible explanation is that the changes of proportions of different aerosol types with increasing AOD have different mechanisms for affecting the macro-physical and micro-physical properties of PSs. The findings provide a valuable insight into how aerosols affect the three-dimensional structure of local-scale PSs over a region with complex aerosol composition.