水动力方法改善品清湖水质的可行性及优化方案

为提升潟湖水环境质量和水动力条件,改善因潮水动力弱、自然条件限制和频繁的人类活动对沿海潟湖脆弱生态环境的影响,文章以亚洲第二大潟湖品清湖为例,基于MIKE21非结构网格建立了品清湖及周边海域二维水动力模型,并在此基础上耦合构建水质模型。通过分析对比品清湖现状与17种改造工况间的水动力及水质的影响变化发现,拆除近岸或者离岸1/2防波堤（工况2和工况3）或同步拆除1/4沙舌和部分崩坎角（工况9）可在较低工程量下有效地改善品清湖水动力及水质,使品清湖的整体平均流速提升10.42%~32.25%,纳潮量增加1.68%~2.48%,水体更新时间缩短21.44%~23.13%,TN和TP浓度分别降低9.0%~10.7%、11.2%~13%;工况2、工况3和工况9各有优势,但不适合共同实施。研究结果不但可为低成本品清湖修复工程提供实施依据,也可为潟湖的水动力、水质改善提供模拟案例。     

“21世纪海上丝绸之路”航运服务业网络格局研究

在"一带一路"倡议下,发展航运服务业对于巩固与提升中国在全球航运网络中的地位具有重要意义。构建103家跨国公司在"21世纪海上丝绸之路(海丝之路)"沿线1 054个城市的分布数据库,分析7种航运服务业在"海丝之路"沿线的网络特征。研究表明:①"海丝之路"沿线航运服务业网络的层级分布特征明显,处于第一层级的均为亚洲城市,说明亚洲航运服务业在航运服务业网络中地位重要。②在"海丝之路"这一层面,伦敦、香港、新加坡等城市和地区构成大的联系三角,在中国层面,上海、香港、北京构成小的联系三角。③高端航运服务业主要分布在欧洲城市,亚洲城市在中端航运服务业方面占据重要地位,在低端航运服务业方面,非洲城市在仓储服务业表现突出,亚洲和欧洲城市则在船舶修造业实力雄厚。④高端航运服务业往往受城市的历史、文化、语言、法律、制度影响较大,对地方的根植性较强,倾向于首都等内陆城市,而中低端航运服务业主要依托于货物运输,受自然条件和区位条件等因素的影响较大,往往随货物运输转移而转移,倾向于分布在港口城市。     

The demographics of energy and mobility poverty: Assessing equity and justice in Ireland,Mexico, and the United Arab Emirates

Energy and mobility poverty limits people’s choices and opportunities and negatively impinges upon structural economic and social welfare patterns. It also hampers the ability of planners to implement more equitable and just decarbonization pathways. Research has revealed that climate policies have imposed a financial burden on low-income and other vulnerable groups by increasing food and energy prices, leading as well to global inequality. Similarly, researchers have warned that in developing countries, emission mitigation policies could increase poverty rates and even frustrate progress towards universal access to clean energy. This research explores whether low-income social groups experience a 'double energy vulnerability', a situation that simultaneously positions people at heightened risk of transport and energy poverty. We investigate this 'double vulnerability' through original data collection via three nationally representative surveys of Mexico (N = 1,205), the United Arab Emirates (N = 1,141), Ireland and Northern Ireland (N = 1,860). We draw from this original data to elaborate on the sociodemographic attributes, expenditure and behaviour emerging from energy and transport use, focusing on themes such as equity, behaviour and vulnerability. We propose energy and transport poverty indexes that allow us to summarize the key contributing factors to energy and transport poverty in the countries studied and uncover a strong correlation between these two salient forms of poverty. Our results suggest that energy and transport poverty are common issues regardless of the very different national, and even sub-national, contexts. We conclude that energy and transport poverty requires target policy interventions suitable for all segments of society, thus enabling contextually-tailored, just energy transitions.     

无人机遥感与XGBoost的红树林物种分类

无人机遥感数据会衍生大量的光谱、纹理与结构特征,如何提取优势特征是提高红树林物种分类效率和精度的关键问题.针对深圳福田红树林自然保护区缓冲区获取的无人机高光谱影像和LiDAR点云数据,本研究旨在利用极端梯度提升算法(XGBoost)的“特征重要性”属性筛选出适合红树林物种分类的8类优势特征:基于无人机高光谱影像的单一特...