基于WebGIS禽流感疫情耗费评估决策系统研究

为在疫情应急反应中提供动态、准确的疫情信息及合理决策,提出了构建禽流感疫情耗费评估决策系统。本文介绍了系统的体系设计、多用途数据库设计及实现该系统的关键技术,主要实现了禽流感疫源空间位置确定、疫区和威胁区的快速划分及禽流感疫情动态耗费评估分析,最后以北京市大兴区为例,实现系统的初步应用。     

基于夜间灯光数据的晋陕蒙能源消费碳排放时空格局

晋陕蒙三省区既是能源生产基地又是碳排放主要地区。对晋陕蒙市县的碳排放估算难度较大,如何准确快捷地获取其碳排放时空动态信息,对于合理制定区域碳减排规划具有重要的应用价值。本文选取中国晋陕蒙三省作为研究对象,基于夜间灯光数据,模拟晋陕蒙地区碳排放空间分布,进而系统地刻画其碳排放空间分布特征和规律。研究结果表明：① 1997-2016年,晋陕蒙三省区夜间灯光像元总值与能源消耗碳排放量之间的相关系数较高,均通过了1%的显著性检验;② 1997-2016 年,晋陕蒙地区的CO₂排放总量呈逐年增长趋势,鄂尔多斯市属于“高碳”地区;铜川市、安康市、商洛市、汉中市、阿拉善盟和阳泉市属于“低碳”地区;③ 陕西省碳排放清晰地呈现出“陕北>关中>陕南”的格局。晋陕蒙地区碳排放空间分布规律分析为该区域制定切实可行的碳减排政策提供了重要的理论依据。     

居民跨界行为的边界研究：以珠澳边界意义重构为例

研究探讨了边界的物理形态及其空间意义,并讨论由跨界行为催生的地方感与地方意象及其对边界空间意义的重构。以珠澳边界（拱北口岸）为案例地,本文主要采用追踪和访谈的研究方法,研究发现：跨越珠澳边界的行为（尤其是由珠海往澳门方向的跨界行为）以个人消费为主,主要包括购物、娱乐和餐饮等,而与之联结的消费地点也大同小异,但也存在不同时代和社会阶层因素对于跨界活动目的的影响,且流动性往往与特定的地方联结,使原有的固定行政边界及其所规定的空间管制逐渐被打破。出于满足生活的需求、社会互动的情感联系,抑或是出于追求地方价值的体验和情感表达,跨界主体成为塑造边界两边地理想象的重要因素,地理想象与现实生活空间的差异形成了想象的边界并间接地作用于珠澳边界空间意义的重构。     

The effects of urban water cycle on energy consumption in Beijing,China

Journal of Geographical Sciences - Energy is consumed at every stage of the cycle of water production, distribution, end use, and recycled water treatment. Understanding the nexus of energy and...     

Analysis of CO2 Emissions and the Mechanism of the Industrial Enterprises above Designated Size (IEDS) in Resource-based Cities by Application of Geographical Detector Technology

Resource-based cities are the most important players in responding to climate change and achieving low carbon development in China. An analysis of relevant data (such as the energy consumption) showed an inter-city differentiation of CO₂ emissions from energy consumption, and suggested an influence of the Industrial Enterprises above Designated Size (IEDS) in resource-based industrial cities at the prefecture level and above in different regions. Then by geographical detector technology, the sizes of each influencing mechanism on CO₂ emissions from energy consumption of the IEDS were probed. This analysis showed that significant spatial differences exist for CO₂ emissions from energy consumption and revealed several factors which influence the IEDS in resource-based cities. (1) In terms of unit employment, Eastern and Western resource-based cities are above the overall level of all resource-based cities; and only Coal resource-based cities far exceeded the overall level among all of the cities in the analysis. (2) In terms of unit gross industrial output value, the Eastern, Central and Western resources-based cities are all above the overall level for all the cities. Here also, only Coal resource-based cities far exceeded the overall level of all resources-based cities. Economic scale and energy structure are the main factors influencing CO₂ emissions from energy consumption of the IEDS in resource-based cities. The factors influencing CO₂ emissions in different regions and types of resource-based cities show significant spatial variations, and the degree of influence that any given factor exerts varies among different regions and types of resource-based cities. Therefore, individualized recommendations should be directed to different regions and types of resource-based cities, so that the strategies and measures of industrial low carbon and transformation should vary greatly according to the specific conditions that exist in each city.     

Alternative approach for dynamic-positioning thrust allocation using linear pseudo-inverse model

Application of ship Dynamic-Positioning systems strongly depends on physical ability of actuators (Thrusters) in providing commanded loads. This will consequently introduce some constraints and limitations to Thrust Allocation problem in design and control of such systems. However, there is a special case in which a simple explicit solution could be found by fixing orientation of azimuth thruster relative to vessel regarded as linear model. In this paper, three new alternative approaches based on linear model are introduced. Case study is a time domain simulation of Station-Keeping (instant Point-Tracking) operation for a supply vessel called Northern Clipper in North Sea with Beaufort number 6. As is evident by results, these approaches improve maneuvering performance and power consumption efficiency compared to the conventional linear model. Results show improved robustness of yaw control in Point-Tracking operation and decreased overall consumption of power compared to linear model. Furthermore, it is apparent from the results that these approaches are particularly efficient in tunnel thrusters compared to linear counterpart.     

Impacts of headcut height on flow energy,sediment yield and surface landform during bank gully erosion processes in the Yuanmou Dry‐hot Valley region,southwest China

To quantify the changes in flow energy, sediment yield and surface landform impacted by headcut height during bank gully erosion, five experimental platforms were constructed with different headcut heights ranging from 25 to 125 cm within an in situ active bank gully head. A series of scouring experiments were conducted under concentrated flow and the changes in flow energy, sediment yield and surface landform were observed. The results showed that great energy consumption occurred at gully head compared to the upstream area and gully bed. The flow energy consumption at gully heads and their contribution rates increased significantly with headcut height. Gully headcuts also contributed more sediment yield than the upstream area. The mean sediment concentrations at the outlet of plots were 2.3 to 7.3 times greater than those at the end of upstream area. Soil loss volume at gully heads and their contribution rates also increased with headcut height significantly. Furthermore, as headcut height increased, the retreat distance of gully heads increased, which was 1.7 to 8.9 times and 1.1 to 3.2 times greater than the incision depth of upstream area and gully beds. Positive correlations were found between energy consumption and soil loss, indicating that energy consumption could be used to estimate soil loss of headcut erosion. Headcut height had a significant impact on flow energy consumption, and thus influenced the changes in sediment yield and landform during the process of gully headcut erosion. Headcut height was one of the important factors for gully erosion control in this region. Further studies are needed to identify the role of headcut height under a wide condition. Copyright © 2018 John Wiley & Sons, Ltd.     

用于拆平台的双船协同动力定位试验研究

大型海洋结构物的退役和拆除是油气行业面临的一个巨大挑战。双船起重拆除法提供了一种低成本、高效、灵活的解决方案,该方案采用两艘具有动力定位功能的半潜运输船从平台两侧将平台上层组块托起,随后协同托举运输至第三艘半潜运输船上后转运送至陆地。在这个过程中涉及到两艘及三艘船的协同动力定位作业,这对动力定位系统的同步性具有很高要求。多船近距离协同动力定位会受到螺旋桨与螺旋桨、船体与船体及螺旋桨与船体之间的干扰,动力定位的性能会受到影响。为此开展了相应的水池模型试验研究,对复杂环境下多船协同动力定位性能进行了分析,包括定位精度、功率消耗等,并对动力定位风险点进行了深入研究,验证了双船起重拆除法的可行性,并对实际工程的施工提供一定指导意见。     

Mercury contamination in Southern New England coastal fisheries and dietary habits of recreational anglers and their families: Implications to human health and issuance of consumption advisories

Total mercury (Hg) was measured in coastal fishes from Southern New England (RI, USA), and Hg exposure was estimated for anglers and family members that consumed these resources. Fish Hg was positively related to total length (n = 2028 across 7 fish species), and interspecies differences were evident among legally harvestable fish. Many recreational anglers and their families experienced excessively high Hg exposure rates, which was attributed to the enriched Hg content of frequently consumed fishes. Specifically, 51.5% of participants in this study had Hg exposures exceeding the US EPA reference dose, including 50.0% of women of childbearing years. These results are noteworthy given that Hg neurotoxicity occurs in adults and children from direct and prenatal low-dose exposure. Moreover, this study underscores the need for geographic-specific research that accounts for small-scale spatial variations in fish Hg and dietary habits of at-risk human populations.     

Effect of spatial resolution of satellite images on estimating the greenness and evapotranspiration of urban green spaces

Urban green spaces (UGS), like most managed land covers, are getting progressively affected by water scarcity and drought. Preserving, restoring and expanding UGS require sustainable management of green and blue water resources to fulfil evapotranspiration (ET) demand for green plant cover. The heterogeneity of UGS with high variation in their microclimates and irrigation practices builds up the complexity of ET estimation. In oversized UGS, areas too large to be measured with in situ ET methods, remote sensing (RS) approaches of ET measurement have the potential to estimate the actual ET. Often in situ approaches are not feasible or too expensive. We studied the effects of spatial resolution using different satellite images, with high-, medium- and coarse-spatial resolutions, on the greenness and ET of UGS using Vegetation Indices (VIs) and VI-based ET, over a 780-ha urban park in Adelaide, Australia. We validated ET with the ground-based ET method of Soil Water Balance. Three sets of imagery from WorldView2, Landsat and MODIS, and three VIs including the Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI) and Enhanced Vegetation Index 2 (EVI2), were used to assess long-term changes of VIs and ET calculated from the different imagery acquired for this study (2011–2018). We found high correspondence between ET-MODIS and ET-Landsat (R² > 0.99 for all VIs). Landsat-VIs captured the seasonal changes of greenness better than MODIS-VIs. We used artificial neural network (ANN) to relate the RS-ET and ground data, and ET-MODIS (EVI2) showed the highest correlation (R² = 0.95 and MSE =0.01 for validation). We found a strong relationship between RS-ET and in situ measurements, even though it was not explicable by simple regressions; black box models helped us to explore their correlation. The methodology used in this research makes a strong case for the value of remote sensing in estimating and managing ET of green spaces in water-limited cities.