The status of beaches and shoreline development options on the French Riviera: a perspective and a prognosis

Beach conservation and management on the high-value French Riviera in southeastern France have had mixed fortunes in shoreline economic development strategies over the past half century. Prior to 1965, socio-economic growth related to immigration and tourism resulted in considerable pressure on the coastal zone, leading in particular to beach erosion and degradation of beach environmental quality. Between 1965 and 1980, over 20% of the 132 km-long French Riviera was permanently altered through the implantation of yachting harbours and reclamation fill structures, while beach-based recreation had a rather low ranking as a development choice, except in the two major resorts of Cannes and Nice which exhibit a densely urbanized seafront. On this preponderantly boldrocky coast, the mediocre recreational value inherited by many of the beaches from the regional geologic setting, and from development pressures and earlier errors in coastal management, left them vulnerable to appropriation and so-called ‘valorization’ by yachting harbour and estate developers. Over the last decade, artificial shoreline development has virtually ceased, in response to several more or less interrelated factors. These include relative stagnation of socio-economic growth, increasing development and maintenance costs of yachting harbours, saturation of the yachting harbour market as a result of the burgeoning of new, often cheaper, resorts and of reconversion of commercial and shipbuilding ports to leisure ports in the Mediterranean, more stringent legislation, since 1986, on the implantation of residential and major engineering structures on the coastline, pressure for conservation of the cultural and environmental heritage, and greater demand for beach recreational space. This situation has forced a diversification of shore-based activities, as it has been realised that better managed beaches may balance economic aspirations while contributing to enhanced environmental quality and sensible shoreline conservation. This change in strategy has entailed considerable efforts and money on the improvement of coastal water quality, the provision of amenities for beach-goers, and especially the nourishment of eroding beaches and the creation of several artificial beaches. The extent to which beaches will continue to play a role in the sustainable development of French Riviera resorts will depend largely on the capacity of local authorities to maintain environmental quality in the face of inherited and persistent handicaps such as beach erosion.     

LES – DFSD modelling of vented hydrogen explosions in a small-scale combustion chamber

Accidental explosions are a plausible danger to the chemical process industries. In the event of a gas explosion, any obstacles placed within the path of the flame generate turbulence, which accelerates the transient flame and raises explosion overpressure, posing a safety hazard. This paper presents numerical studies using an in-house computational fluid dynamics (CFD) model for lean premixed hydrogen/air flame propagations with an equivalence ratio of 0.7. A laboratory-scale combustion chamber is used with repeated solid obstacles. The transient compressible large eddy simulation (LES) modelling technique combined with a dynamic flame surface density (DFSD) combustion model is used to carry out the numerical simulations in three-dimensional space. The study presented uses eight different baffle configurations with two solid obstructions, which have area blockage ratios of 0.24 and 0.5. The flame speed, maximum rate of pressure-rise as well as peak overpressure magnitude and timing are presented and discussed. Numerical results are validated against available published experimental data. It is concluded that, increasing the solid obstacle area blockage ratio and the number of consecutive baffles results in a raised maximum rate of pressure rise, higher peak explosion overpressure and faster flame propagation. Future model development would require more experimental data, probably in a more congested configuration.     

城市生态示范区建设成效层次模糊综合评价研究

将层次模糊综合评价模型应用于生态示范区指标体系,采用专家调查法构造判断矩阵,确定了指标权重,并对生态示范区建设指标体系进行分级,评价了长沙市开福区生态示范区建设的成效。结果表明,长沙市开福区自开展生态示范区建设以来,在社会、经济和生态环境领域都取得了明显进步,2002年至2003年时间段的成效尤为显著。     

关中地区PM2.5污染过程的主要参数特征和EMD统计分析

为了掌握关中地区的污染过程特征,并为关中地区预警预报提供理论支撑,利用2014—2017年关中地区五市（西安市、咸阳市、宝鸡市、渭南市、铜川市）ρ（PM_2.5）数据,对该地区PM_2.5污染过程的峰值质量浓度、持续时间等特征进行统计分析,并用EMD（经验模态分解法）分解海平面气压观测数据,对PM_2.5污染过程的统计结果进行解释.结果表明:①关中地区ρ（PM_2.5）分布在时间和空间上均具有显著的区域相关和时间同步特征.各城市的ρ（PM_2.5）日均值较接近,相差范围为2~15 μg/m3.②污染过程持续时间的统计表明,冬季污染过程持续时间（11~15 d）相对较长,夏季污染过程持续时间（7~9 d）相对较短;PM_2.5污染过程的峰值质量浓度分析表明,各城市中度及以上等级的污染频次差异较大,最大值出现在咸阳市,为16次,最小值出现在铜川市,为9次.③利用EMD算法对气压数据进行分解后发现,第4模态（IMF4）的震荡频率变化是关中地区各城市不同季节污染过程持续时间存在明显差异的主要原因.研究显示,单站气压的EMD模态分解可以较好地解释关中地区的污染物浓度特征.      

基于生态足迹的三峡库区重庆段后续发展生态补偿标准量化研究

生态足迹思想被引入我国后,受到了许多学者的关注,结合生态系统服务价值相关理论,可以量化生态补偿标准.本文以重庆三峡库区为研究对象,通过基于"省公顷"的模型改进方法修正模型,计算生态足迹与生态承载力,得到其空间分异特征,引入生态系统服务价值,构建基于生态足迹的三峡库区后续发展生态补偿标准模型,并计算各个区县的生态补偿标准,与其他大型库区的生态补偿结果进行对比.研究结果表明:在2010—2016年,重庆三峡库区的平均生态足迹为34586160.120 hm~2,平均生态承载力为6664208.176 hm~2,通过对重庆段的所有区县进行生态安全判断,发现全部都是处于不安全状态,需要进行生态补偿.整体上,生态补偿需补偿约54.92亿元.而人均补偿额度小于100元的有大渡口区、奉节县、石柱县、巫山县、巫溪县、云阳县和忠县7个区县,在100～200元有长寿区、丰都县、开州区和武隆区4个区县,在200～300元的有巴南区和北碚区2个区县,在300～400元的有万州区、江北区、江津区、涪陵区和南岸区5个区县,大于400元的有沙坪坝区、渝中区、渝北区和九龙坡区4个区县.随着经济发展,必定会带来生态足迹与生态承载力的改变,生态补偿额度也会相应的增加.     

基于“三生空间”的土地利用功能转型及生态服务价值研究——以福州新区为例

分析土地利用功能转型及带来的生态服务价值转变,是快速城镇化地区土地资源开发利用和“三生空间”管控的重要依据。论文基于福州新区2000、2009和2015年3期Landsat ETM+/OLI遥感数据和“三生”土地利用主导功能分类体系,应用GIS定量研究了福州新区15 a土地利用功能转型特征及生态系统服务价值时空演变,结果表明： 1）15 a间福州新区的生活生产空间增长迅速,面积增加了11 224.63 hm²,增长率达82.31%;生态生产空间面积出现先下降后增长趋势,总体增长了19.94%;生活生产空间的增长源于对生态空间和生产生态空间的侵占,生态生产空间的增长源于对湿地、海域等生态空间的侵占。2）15 a间福州新区生态系统服务价值下降了21.69%,其中生态空间下降总量最大,减少了6.822 8亿元,生活生产空间下降幅度最大,下降了92.10%。3）区域生态系统服务价值存在提高和下降两种相反趋势,导致研究区生态系统服务价值降低的主要原因是生活生产空间对生态空间和生产生态空间的侵占,贡献率分别达38.60%和18.77%,其次为生态生产空间对生态空间的侵占。4）推进福州新区“三生空间”协同布局,应加强区内生态林地、闽江河口、海岸线等重点生态空间的保护,稳步推进新区核心区域生活空间基础设施优化,集约利用生产空间,增加产出效益。     

南水北调对湖北丹江口水库区土地资源的影响

湖北省丹江口水库区是南水北调中线工程的水源区。随着调水工程的实施,库区土地资源将受到深远的影响。以丹江口水库及其四周海拔低于２００ｍ的区域为研究范围,选用９０年代初获取的ＬａｎｄｓａｔＴＭ假彩色合成图像为主信息源,运用目视判读和地理信息系统（ＧＩＳ）方法,对该区的土地资源利用现状进行了比例尺为２５万分之一的遥感制图和计算机面积量算;在此基础上,对工程实施后本区土地资源的淹没损失、土地利用结构的变化进行了宏观分析,进而对区域土地资源的合理利用进行了初步探讨。     

华北山区大气气溶胶浓度及其尺度谱分布的研究

1980年3月,我们在北京北部山区,用光学粒子计数器观测了“干净”地区近地层大气气溶胶浓度与尺度谱分布。发现“有霾”大气气溶胶的浓度及其尺度谱分布的变化特征具有特殊性。计算表明,三参数谱模式的拟合效果较好。     

城市生态环境需水量研究

在探讨城市生态环境需水量基本概念和特点的基础上 ,对其进行分类 ,并发展了较为系统的研究方法 ,提出目前适宜的方法是从城市现状出发 ,将城市综合性分类与城市生态环境质量指标等级相结合 .以黄淮海地区城市为例 ,估算了该地区城市生态环境需水量等级 ,计算结果表明 :黄淮海地区城市最小和最优生态环境需水量分别为 39 34亿m3 和 187 82亿m3 ,最小生态环境需水量在城市供水中的比例为 5 2 7%.