Urbanization effect on precipitation over the Pearl River Delta based on CMORPH data

Based on the satellite data from the Climate Prediction Center morphing(CMORPH) at very high spatial and temporal resolution, the effects of urbanization on precipitation were assessed over the Pearl River Delta(PRD) metropolitan regions of China. CMORPH data well estimates the precipitation features over the PRD. Compared to the surrounding rural areas, the PRD urban areas experience fewer and shorter precipitation events with a lower precipitation frequency(ratio of rainy hours, about 3 days per year less); however, short-duration heavy rain events play a more significant role over the PRD urban areas. Afternoon precipitation is much more pronounced over the PRD urban areas than the surrounding rural areas, which is probably because of the increase in short-duration heavy rain over urban areas.

Spatial Effect of Mineral Resources Exploitation on Urbanization:A Case Study of Tarim River Basin,Xinjiang,China

Mineral resources exploitation significantly affects the spatial structure and evolutive trend of urbanization in arid areas.In this study,the spatial autocorrelation method and the spatial computation model were used to investigate the spatial impacts of mineral resources excavation and processing on comprehensive level of urbanization in the Tarim River Basin,Xinjiang,China for the years of 2000,2006 and 2008.The results are as follows:1)There was a spatial correlation of the development of mineral resources industry and the comprehensive level of urbanization in 2006 and 2008,with the spatial concentration trend rising significantly in 2006 and decreasing in 2008.2)The patterns of local spatial concentration of mineral resources industry and of the comprehensive level of urbanization were relatively stable,and the two patterns showed signs of spatial correlationship.The higher was the degree of the concentration of mineral resources industry,the stronger was its impact on the spatial clustering of urbanization.3)In 2000, mineral resources excavation and processing had a significant positive impact on the comprehensive level of urbanization in the region but not in its adjacent regions.However,in 2008,mineral resources excavation and processing significantly raised the comprehensive level of urbanization not only in the region but also in its neighboring regions.This research demonstrates that the development of mineral resources industry can strongly affect the trends and spatial patterns of urbanization.

Mountain Effect and Differences in Storm Floods between Northern and Southern Sources of the Songhua River Basin

In this study, the differences in annual rainstorm changes in the Second Songhua River Basin and the Nenjiang River basin and their causes were compared from the perspective of mountain effects. The following results were drawn: (1) Altitude effect is the primary factor leading to increased rainstorms in the southern source; (2) Slope effect primarily leads to differences of the weather systems in the two sources, and thus cause the difference of the rainstorms; (3) Slope effect is responsible for the greater fluctuation in the observed floods in the southern source. These landform differences eventually lead to the differences in the characteristics of floods in the southern and northern sources. Commensurability method was used to identify the period of rainstorms in the southern and northern sources. The results showed that although rainstorms do not appear at the same time in the two sources they are characteristic of a 10 years' period in both areas. These results can serve as hydrological references for flood control and long-term flood disaster predictions.

Scale effects of eroded sediment transport in Wujiang River Basin, Guizhou Province, China

In recent years, research on spatial scale and scale transformation of eroded sediment transport has become a forefront field in current soil erosion research, but there are very few studies on the scale effect problem in Karst regions of China. Here we quantitatively extracted five main factors influencing soil erosion, namely rainfall erosivity, soil erodibility, vegetative cover and management, soil and water conservation, and slope length and steepness. Regression relations were built between these factors and also the sediment transport modulus and drainage area, so as to initially analyze and discuss scale effects on sediment transport in the Wujiang River Basin(WRB). The size and extent of soil erosion influencing factors in the WRB were gauged from: Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model(ASTER GDEM), precipitation data, land use, soil type and Normalized Difference Vegetation Index(NDVI) data from Global Inventory Modeling and Mapping Studies(GIMMS) or Advanced Very High Resolution Radiometer(AVHRR), and observed data from hydrometric stations. We find that scaling effects exist between the sediment transport modulus and the drainage area. Scaling effects are expressed after logarithmic transformation by a quadratic function regression relationship where the sediment transport modulus increases before decreasing, alongside changes in the drainage area. Among the five factors influencing soil erosion, slope length and steepness increases first and then decreases, alongside changes in the drainage area, and are the main factors determining the relationship between sediment transport modulus and drainage area. To eliminate the influence of scale effects on our results, we mapped the sediment yield modulus of the entire WRB, adopting a 1 000 km^2 standard area with a smaller fitting error for all sub-basins, and using the common Kriging interpolation method.

Effects of reservoirs on seasonal discharge of Irtysh River measured by Lepage test

The Irtysh River is an intemational river partially joining the territories of China, Kazakhstan, and Russia. Cascade reservoirs have been constructed in the upper reaches of the river and their effects on the seasonal discharge of the middle and lower reaches were analyzed considering the mean and dispersion of the seasonal discharge. The Lepage test, which is a nonparametric, two-sample test for detecting location and dispersion, was used to measure the significance of difference between the pre-dam and post-dam seasonal discharge. The results show that the reservoirs＇ effects on the seasonal discharge varied with the season. In the middle reaches of the river, the summer and autumn discharge decreased significantly and their inter-annual variabilities also decreased significantly. The summer and autumn precipitation over the Irtysh River Basin changed little before and after the operation of the reservoir, which indicates that the discharge changes mainly due to water storage of the reservoirs. The reservoirs store water in summer and autumn and store more water in a wet year, which leads to the reduction of the mean and dispersion of the summer and autumn discharge. The winter discharge increased significantly because the reservoirs released water for power generation. The spring discharge changed slightly. In the lower reaches, only the winter discharge increased significantly, and the other seasonal discharge changed slightly. The reservoirs＇ effects on the seasonal discharge are more significant in the middle reaches than in the lower reaches.

An Evaluation of Artificial Fish Nest for Assessment Enhancement Effects of Fishery Resources of in Xiangjiang River

Artificial fish nests are set in Lukou section and Hengyang section of Xiangjiang River from March 20 to May 10, 2019. The structure of artificial fish nest is bamboo frame, with the size of 2.5 m × 5.0 m × 4 and a unit frame area of 60 m2. A total of 58,201 eggs were collected by 24 monitoring times, of which 30,441 were from Lukou and 27,760 from Hengyang. 3831 fish eggs identify 8 fish species using morphological or molecular biological methods. The results showed that the number of eggs peaked from the 8th day to the 24th day after the nest entered the water, and then decreased rapidly. There was significant negative correlation between egg number in per m2 fish nest and days of fish nest (P < 0.01). The economic benefits of artificial fish nests were RMB 11.81 million. The artificial fish nest can not only increase the population of fish, but also has significant economic benefits.

Analysis of ecological effects of comprehensive treatment in the Tarim River Basin using remote sensing data

Based on multi-type,multi-temporal remote sensing data,we have monitored recent changes in cultivated land use and vegetation,in sandy areas and salinized desertification in the Green Corridor zone of the main channel of the Tarim River Basin.The results of our investigation show that the ecological environment in the Green Corridor of the main channel of the Tarim River Basin has conspicuously improved from 2002 to 2004.These improvements show up largely in such aspects as an increase in the rate of vegetation cover,a reduction in desertification land areas and a weakening in the intensity of sandy and the salinized land.On the other hand,the cultivated area in the Tarim River Basin significantly increased from 2002 to 2004.The rate of growth in cultivated areas during this period was significantly higher than that from 1999 to 2002.The increase in the use of irrigation resulting from the substantial increase in cultivated areas has a long-term potential restraining effect on the restoration of ecological functions of the Tarim River.

FDI and the technological spillover effects: a comparative analysis on the Yangtze River Delta and the Pearl River Delta

This article calculates the technological spillover effects of foreign direct investment (FDI) in the Yangtze River Delta and the Pearl River Delta through Panel Data, and analyzes the influence on the technological spillover effects of the following factors in these two different areas: human capital, the opening up, R&D and the source of FDI. It makes the conclusion that FDI in different areas has different technological spillover effects and the local governments should make different policies accordingly so as to gain more obvious technology spillover effects.

水土保持生态建设下的黄土高原典型流域水沙响应

为探讨黄土高原多沙粗沙区流域水沙关系演变特征及其对水土流失治理的响应,以黄河中游无定河流域为研究对象,综合采用水沙关系曲线、数理统计等多种方法,系统分析1956—2019年间无定河流域水沙关系多时间尺度演变特征及其与水土流失治理的协同响应。研究结果表明:1)研究时段内,无定河流域年径流及年输沙量呈锐减趋势(P<0.05),且均在1970年左右发生减少突变;2)流域水沙关系在年际和场次洪水尺度上均发生深刻变化。2010年以后,暴雨频发导致流域内侵蚀物源头供应明显增加,流域河道泥沙输送能力小幅提高;3)水土保持措施实施对流域水沙锐减影响较大。2000年前后在相似降雨条件下,单位降雨量径流量和单位降雨量输沙量较20世纪70年代减少47%和62%。水土保持措施面积增加与流域径流输沙减少呈现较好的一致性,流域水土流失治理在提高黄河多沙粗沙区流域下垫面抗侵蚀能力等方面发挥重要作用。研究结果可为科学认知区域水土流失治理成效及入黄泥沙锐减成因提供参考。

Environmental effects of export trade in the Yangtze River Delta, 2003-2006

Economic globalization has promoted the formation of global production network, and correspondingly the high quality environmental factors are reconfigured behind the physical commodities exchange. Export trade not only drives China's economic growth, promotes industrial upgrading and technological progress, but also may have a negative impact on the environment. After reviewing and summarizing the existing relevant literatures, the paper collects the required statistic data from 2003 to 2006 and uses the panel data model to measure the environmental effects of export trade in the Yangtze River Delta. The results show that the export trade of Yangtze River Delta has a negative impact on the environment. When the variables of economic scale, economic structure are fixed, with the export trade growth of 1%, the industrial sulfur dioxide emission and industrial waste water emission will increase by 0.12% and 0.23% respectively. So we must pay serious attention to the negative effects, and promote regional sus tainable development rapidly through adjusting the export structure and strengthening environmental regulations.

Downstream effects of reservoirs in areas suffering from water deficiency-the case of Hutuo River, China

The Hutuo River is located in the semi-arid areas in China. Due to fat of water resources in these areas, changes in flow regime, mainly reduction in runoff downstream from the reservoirs, have been tremendous. As a result of decrease in flow power and sediment load, the post-dam river showed a less change in channel morphology and the change varied reach by reach. Comparatively, the channel shrinkage may contribute to the flood disasters in the lower reaches of the river in recent years. An obvious increase of channel's hydraulic roughness, the main cause for reduction of flood transmission capacity of the channel, is attributed to vegetation encroachment in the channel. The effects of reservoir construction on ground water level and other environmental aspects are also discussed in the paper.

黄河口泥沙的治理实践与评价

基于1855年以来黄河口的来沙量及其不同时期河口泥沙的输移分布特征,从入海流路、防洪安全、下游河道淤积和航道建设等4个方面对黄河口泥沙的灾害效应进行了论证分析。在总结黄河口泥沙治理历史的基础上,从防洪工程体系建设、强化河口河段泄洪排沙能力、减少河口来沙等3个方面对20世纪70年代中期以来黄河口所采取的泥沙处理对策进行了概括总结。结合国内外相关典型河口泥沙的治理经验和发展态势,从水沙关系调控、入海流路格局优化、利用海洋动力输沙和泥沙资源化利用等方面提出了今后黄河口泥沙的治理方向和主要策略。

河湖长制背景下复苏河湖生态环境路径探析

河湖长制是一项基于我国政治制度和国家治理结构而设计的重大制度创新,实施7年多来,取得了显著成效。复苏河湖生态环境是推动新阶段水利高质量发展的六条实施路径之一,不仅涉及工程技术问题,更重要的是面临着理念、制度和管理层面突破创新的挑战。在分析河湖长制制度效能的基础上,从体制机制、保护治理和制度政策3个维度探讨了复苏河湖生态环境的路径选择问题。研究建议:以河湖长制为复苏河湖生态环境的有力手段和重要的体制机制保障,将河湖长制的制度优势转化为河湖治理效能,统筹各方力量共同推进河湖保护治理;以建设幸福河湖为目标,通过系统治理、综合治理、源头治理,推动复苏河湖生态环境各项任务落实;将健全复苏河湖生态环境的制度和标准体系作为复苏河湖生态环境的政策制度路径。

Integrating Downstream Ecological, Social and Economic Effects of Hydropower to Hydraulic Modeling: A Review

Hydropower gains increasing importance as a steerable and controllable power source in a renewable energy mix and deregulated markets. Although hydropower produces fossil-free energy, it has a significant impact on the local environment. This review investigates the effects of flow alterations by hydropower on the downstream river system and the possibilities to integrate these effects into hydraulic modeling. The results show that various effects of flow regulation on the ecosystem, but also social and economic effects on related communities were observed in the last decades. The application of hydraulic models for investigations of ecological effects is common. Especially hydraulic effects and effects on fish were extensively modeled with the help of hydraulic 1D- and 2D-simulations. Current applications to investigate social and economic effects integrated into hydraulic modeling are meanwhile limited. Approaches to realizing this integration are presented. Further research on the economic valuation of ecosystems and integration of social and economic effects to hydraulic models is necessary to develop holistic tools to support decision-making on sustainable hydropower.

Possible effect of climate changes on the coastal zone of the Yangtze River Delta

A coastal historical evolution of the Yangtze River Delta was discussed in this paper on the basis of the historical data of the coastal zone and an estimation was made for the future change of the coast The emphasis was put on the future climate change that will have influence on the sea wall, coastal navigation and freshwater resources in the Delta It was also pointed out that the global warming and precipitation increase in the Yangtze River Valley may exert more impact on the zone In addition, some measures describing how to adapt to the climate change and reduce its impact were put forward

产业链韧性对经济高质量发展的影响

基于2011—2022年长三角地区41个城市的面板数据,运用计量模型,分析研究了产业链韧性对经济高质量发展的影响效果及作用机制,并构建空间杜宾模型探索了产业链韧性对经济高质量发展的空间效应影响。结果表明:产业链韧性对经济高质量发展有显著正向作用;产业链韧性可以通过产业结构升级和产业创新两条路径来促进经济高质量发展;产业链韧性对于都市圈内城市和区位更具优势的城市的经济高质量发展的促进效果更明显;产业链韧性提升对周边城市经济高质量发展存在正向溢出效应。认为应从产业链延链补链强链、改善创新环境、做大产业集群等方面提升产业链韧性,推动产业转型升级和产业创新,促进经济高质量发展。

数字经济对城市高质量发展的影响及其空间溢出效应——以长三角地区为例

伴随新一代信息技术的发展,数字技术广泛应用于城市各领域,为实现我国城市高质量发展带来新的机遇。以2011—2021年长江三角洲地区的41个地级市为研究对象,采用基准回归模型和门槛回归模型分析数字经济对城市高质量发展的影响,并运用空间杜宾模型分析数字经济对城市高质量发展影响的空间溢出效应。研究发现:数字经济促进城市高质量发展,数字经济对城市高质量发展的促进效应受产业结构与城镇化率的门槛效应的影响,且数字经济能够带动邻近地区的城市高质量发展。由此,长三角地区需加快推进数字经济基础设施建设,提高数字经济的发展水平,推动城市高质量发展。

基于河网水动力模型的水系连通性对水环境质量的影响分析研究

平原河网地区地势平坦流速较缓,水体抗污染能力弱,改善水系连通性对水环境质量提升至关重要。以水系连通性较差的盛泽镇跃进联圩为研究对象,通过开展引调水试验,构建圩区河网水动力模型,探索圩区水利工作调度运行规则、河网水系连通方法以及相应的水环境变化规律。研究以水龄作为水系连通性的一种时间尺度参量,建立了跃进联圩水动力-水质-水龄的河网水环境模型,模拟了5种引调水方案下,圩内水系连通性及水质改善情况,并构建了压力、状态与响应的引调水连通效果评估体系,实现了对水系连通性变化与水环境改善水平的定量分析。结果表明:从水体交换时长来看,研究区域主要河道水体交换时间在5天以内,水体连通性越好的河道,水龄越短;从水质指标变化来看,调水实验中圩内的水环境氨氮变化最为明显,对引调水响应度高,模拟结果显示水龄与氨氮浓度变化趋势基本一致,水体连通性越好,水龄越短,有利于氨氮的削减;从引调水方案来看,单一调度方式对圩内水系连通性改善能力有限,特别是在河网内水体流动性弱的区域,同时使得圩区内水体流动性差异增大,更容易造成河网内水系连通性以及水质的空间分布差异,形成局部的滞水区或死水区。因此,采用多源引水与多区域排水相配合的调度方式,可以加强水系连通性,改善水环境质量。

贸易便利化对黄河流域农产品出口二元边际影响的空间效应

随着经济全球化和国际贸易的发展,贸易便利化逐渐成为全球经贸新规则的核心要素。本文基于经济双循环和黄河流域生态保护与高质量发展的内在要求,通过构建指标体系综合评估沿黄九省区的贸易便利化水平,利用二元边际效应,对贸易便利化的构成要素在不同贸易增长维度上的作用进行了细化分解,并对影响的空间效应进行分析。研究发现,以基础设施质量、商务信息技术效率、海关与贸易环境、政府管理水平、金融服务质量表征的贸易便利化水平,均对黄河流域贸易的集约边际表现出正向的促进作用,且影响显著。