Immersive virtual reality and environmental noise assessment: An innovative audio–visual approach

Several international studies have shown that traffic noise has a negative impact on people's health and that people's annoyance does not depend only on noise energetic levels, but rather on multi-perceptual factors. The combination of virtual reality technology and audio rendering techniques allow us to experiment a new approach for environmental noise assessment that can help to investigate in advance the potential negative effects of noise associated with a specific project and that in turn can help designers to make educated decisions. In the present study, the audio–visual impact of a new motorway project on people has been assessed by means of immersive virtual reality technology. In particular, participants were exposed to 3D reconstructions of an actual landscape without the projected motorway (ante operam condition), and of the same landscape with the projected motorway (post operam condition). Furthermore, individuals' reactions to noise were assessed by means of objective cognitive measures (short term verbal memory and executive functions) and subjective evaluations (noise and visual annoyance). Overall, the results showed that the introduction of a projected motorway in the environment can have immediate detrimental effects of people's well-being depending on the distance from the noise source. In particular, noise due to the new infrastructure seems to exert a negative influence on short term verbal memory and to increase both visual and noise annoyance. The theoretical and practical implications of these findings are discussed.     

Living with a large reduction in permited loading by using a hydrograph-controlled release scheme

The Total Maximum Daily Load (TMDL) for ammonia and biochemical oxygen demand for the Pee Dee, Waccamaw, and Atlantic Intracoastal Waterway system near Myrtle Beach, South Carolina, mandated a 60-percent reduction in point-source loading. For waters with a naturally low background dissolved-oxygen concentrations, South Carolina anti-degradation rules in the water-quality regulations allows a permitted discharger a reduction of dissolved oxygen of 0.1 milligrams per liter (mg/L). This is known as the 0.1 rule. Permitted dischargers within this region of the State operate under the 0.1 rule and cannot cause a cumulative impact greater than 0.1 mg/L on dissolved-oxygen concentrations. For municipal water-reclamation facilities to serve the rapidly growing resort and retirement community near Myrtle Beach, a variable loading scheme was developed to allow dischargers to utilize increased assimilative capacity during higher streamflow conditions while still meeting the requirements of a recently established TMDL.As part of the TMDL development, an extensive real-time data-collection network was established in the lower Waccamaw and Pee Dee River watershed where continuous measurements of streamflow, water level, dissolved oxygen, temperature, and specific conductance are collected. In addition, the dynamic BRANCH/BLTM models were calibrated and validated to simulate the water quality and tidal dynamics of the system. The assimilative capacities for various streamflows were also analyzed.The variable-loading scheme established total loadings for three streamflow levels. Model simulations show the results from the additional loading to be less than a 0.1mg/L reduction in dissolved oxygen. As part of the loading scheme, the real-time network was redesigned to monitor streamflow entering the study area and water-quality conditions in the location of dissolved-oxygen sags. The study reveals how one group of permit holders used a variable-loading scheme to implement restrictive permit limits without experiencing prohibitive capital expenditures or initiating a lengthy appeals process.     

基于多卫星遥感的东北地区霾污染时空特征研究

利用多卫星(MODIS、CALIPSO、VIIRS)观测的气溶胶产品、地面空气质量监测数据和气象资料,获取了东北地区2006—2015年期间气溶胶光学厚度(AOD)的季节和年际变化特征,并对2014年10月14日东北地区一次典型重霾污染过程的特征及其潜在传输路径进行了深入讨论.研究结果显示,自2008年起东北地区灰霾污染范围扩大且污染程度加剧,呈带状空间分布(营口-长春-哈尔滨);区域内AOD值呈春、秋和冬季高,夏季低的时间变化特征.采用CALIPSO星载激光雷达数据与MODIS、VIIRS卫星获取的AOD开展综合分析,可有效弥补MODIS、VIIRS卫星因冬季积雪亮地表干扰所产生的AOD缺省区域,增强对长期积雪覆盖地区霾污染的时空特征分析能力.与反映霾污染空间分布范围更广的VIIRS卫星相比,MODIS卫星AOD值与东北地区地面观测获取的AQI、PM10和PM2.5相关系数更高,分别为0.89、0.73和0.83.进一步研究结果显示,秋末冬初东北地区的霾污染事件与农作物秸秆焚烧有关,同时,华北地区灰霾污染可跨越渤海湾传输至东北地区,进一步形成更大尺度的带状区域污染.     

Institutional effectiveness of REDD+ MRV: Countries progress in implementing technical guidelines and good governance requirements

The UNFCCC requires REDD+ countries wishing to receive results-based payments to measure, report and verify (MRV) REDD+ impacts; and outlines technical guidelines and good governance requirements for MRV. This article examines institutional effectiveness of REDD+ MRV by assessing countries’ progress in implementing these technical guidelines and good governance requirements, from three dimensions. Ownership of technical methods examines whether countries own technical methods for forest area and area change measuring, and for estimating forest carbon stocks; and whether national MRV systems cover all forests, land uses and carbon pools. Administrative capacity examines development of administrative competence to implement MRV. Good governance examines whether countries espouses norms of good governance in their MRV systems. We apply these dimensions to assess and compare progress in 13 REDD+ countries, based on a review of national and international documents. Findings show that REDD+ countries have high to very high ownership of technical methods. However, majority ranks only low to moderate on administrative capacity and good governance. This means that although countries have started developing technical methods for MRV, they are yet to develop the competence necessary to administer MRV and to inculcate good governance in MRV. The article explain the scores and suggest ways of improving implementation of REDD+ MRV.     

神经网络模型用于数值水质模型逼近的适用性及非敏感参数的欺骗效应

水质模型被广泛应用于水环境管理和决策,但却面临着计算时间和模型应用效率等多方面的问题;利用函数映射和逼近等方法来建立水质模型的输入-输出响应关系,可有效减少计算成本并显著改善模型效率.水质模型的输入-输出响应函数关系有多种形式,本文以其中的2种为例,并分别基于2个水质模型(零维总磷模型、WASP/EUTRO5)的案例,分析和验证了神经网络模型在响应关系逼近中的适用性.案例的结果表明:神经网络函数可以有效地用于水质模型输入-输出响应关系的逼近;当网络规模超出阈值大小时,神经网络函数逼近的准确度和泛化度对网络规模不敏感.在案例研究的基础上,推导和讨论了在神经网络模型函数映射过程中所可能出现的非敏感参数的欺骗效应,以及可能由此导致的过度预测或过低预测问题;并建议在神经网络函数逼近中,应只包含水质模型的敏感参数,以防止降低神经网络模型的准确度.     

Application of a three-dimensional eutrophication model for the Beijing Guanting Reservoir, China

The Beijing Guanting Reservoir (BGR) is located northwest of Beijing and has been an important water supply reservoir ever since the construction of a dam near the town of Guanting in 1954. As a result of excessive nutrients and organic carbon loadings from the drainage basin over the last several decades, the BGR suffers from eutrophication as well as other contamination problems and has not been used as a drinking water supply reservoir since 1997. As a management step to restore the reservoir's water quality, a numerical model was developed based on the environmental fluid dynamics code (EFDC) framework. The model simulated three phytoplankton species based on the observed cyanobacteria, green algae, and diatom concentrations in 2004 for the Yongding arm of the reservoir, which is separated from the rest of the reservoir by a sand bar. The model was calibrated with vertical temperature profiles as well as the observed chlorophyll a and nutrients concentrations in the water column. The calibrated model was further applied to investigate management scenarios, which include reduction in external loadings of nutrients with constructed wetlands, biomanipulation, and transferring water from CeTian Reservoir. All three scenarios can reduce the peak chlorophyll a levels in the reservoir. The background nutrients were high, and reducing the external nutrients was effective only after a reduction in background nutrients after phytoplankton growth. The biomanipulation and water transfer scenarios could also delay the occurrence of the peak chlorophyll a. Because the model was developed based on one year of data, the model can only reveal the short-term effects of applying the management scenarios. Future studies will consider the long-term processes, such as diagenesis, when data are available to predict the long-term effects of the scenarios.