Application of Unmanned Aerial Vehicles Low-altitude Photogrammetry in Investigation and Evaluation of Loess Landslide

The new technology of UAVs low-altitude photogrammetry is a new three-dimensional space technology after radar remote sensing and 3D laser scanning. This technology has many advantages in the aspect of acquiring 3D point cloud data, such as large area operation, high-accuracy and capturing 3D geographical information quickly. With the algorithm improvement and commercialization development of low-altitude photogrammetry, this new technology is widely used in various fields in foreign countries. This new technology shows a tendency of rapid development in China, especially in the field of surveying and mapping, but in the geological and geotechnical engineering field is at a tentative stage. Based on briefly introducing the new technology of the basic principle and 3D data acquisition method, combined with an example about loess landslide investigation at Heifangtai tableland in Gansu Province, this paper described the application effect of the new technology in the regional landslide investigation and individual landslide investigation. The results showed as follows: ①We could greatly understand the regional spatial distribution of loess landslide in the regional landslide investigation. ②We learned the development characteristics and disaster process of the landslide by means of analyzing pre-sliding and post-sliding low-altitude photogrammetry datum in individual landslide investigation. Thus, UAVs low-altitude photogrammetry technology has broad prospects and research value in the field of geotechnical engineering and geological engineering application.     

关中、陕南及周边地区尾波衰减特性（Qc）研究

根据单次散射模型的尾波功率谱分析方法,利用陕西数字地震台网宽频带数字地震波形记录资料,计算了关中陕南及周边地区13个频段的Qc值。结果显示:在2ts~35 s的时间窗内,Q0值在37.54~72.59之间,全区平均值为58.44,在上升运动显著的秦岭山脉值较大,关中盆地和陕南值较小;在2ts~70 s的时间窗内,Q0值在194.74~283.50 之间,全区平均值为186.79,莫霍界面高波速区值较大,低速区和低速梯度带值较小。     

Continental impact on marine boundary layer coarse particles over the Atlantic Ocean between Europe and Antarctica

Aerosol samples were collected in the Atlantic marine boundary layer between the English Channel and Antarctica during November–December 1999. The composition of coarse (aerodynamic diameter 1–3 μm) individual aerosol particles was studied using the SEM/EDX method. The major particle types observed were fresh sea salt, sea-salt particles reacted partly or totally with sulphuric acid or nitric acid, Mg-sulphate, Ca-sulphate, mixed aluminosilicates and sea salt, aluminosilicates, Ca-rich particles and Fe-rich particles. The relative fractions of sea-salt particles with moderate or strong Cl depletion were high near the coasts of Europe (65–74%) and Northern Africa (44–87%), low far from the coast of Western Africa (10–20%) and very low in remote sea areas between Africa and Antarctica (1%). The Cl depletion was strongest when air masses arrived from the direction of anthropogenic pollution sources. The fractions of Mg-sulphate particles were high (18–25%) in 2 samples near Europe. The Mg-sulphate particles were probably formed as a result of fractional recrystallization of sea-salt particles in which Cl was substituted by sulphate. It remained unclear whether these particles were formed in the atmosphere or during and after sampling. The relative fractions of particles from continental sources were quite low (10–15%) near Europe, very high (25–78%) near the coast of Northwestern Africa and very low in the remote sea areas (0–2%). Most of the continental particles were aluminosilicates and some of them were internally mixed with sea salt. Near the coast of Northwestern Africa, the main source of aluminosilicates was Saharan dust, and near the Gulf of Guinea, emissions from biomass burning were also mixed with aluminosilicates and sea salt.     

Space-time accessibility measures: A geocomputational algorithm with a focus on the feasible opportunity set and possible activity duration

 Space-time accessibility measures have received much attention in recent years due to their sensitivity to differences in individual ability to participate in activities in space and time. Despite the conceptual attractiveness and robustness of space-time measures, only few attempts have been made to operationalize them to date. Research that seeks to improve space-time accessibility measures is still sorely needed. This study seeks to enhance space-time accessibility measures through developing a new operational method and GIS-based algorithm that better represents the space-time characteristics of urban opportunities (e.g. their geographical distribution and opening hours) and human activity-travel behavior (e.g. delay times, minimum activity participation time, and maximum travel time threshold). The proposed method not only takes into account the number and size of opportunities, but also the possible activity duration at each activity location given its opening hours and the effect of transport network topology (e.g. one-way streets, turn restrictions and over-pass). Incorporating these elements into space-time measures helps overcome several shortcomings of previous approaches to evaluating space-time accessibility. Received: 15 September 2002 / Accepted: 10 February 2003 A version of this paper was presented at the 98th Annual Meeting of the Association of American Geographers, Los Angeles, March 19-23, 2002. We thank Joe Weber for providing the digital transport network with travel speeds and a version of the geocomputational algorithm he used in his study (Weber 2001), upon which our developmental effort has been based. We are also grateful to the helpful comments and suggestions of the reviewers.     

Comparison of physical and chemical properties of maceral groups separated by density dradient centrifugation

Eight coals have been selected for study of the physical and chemical properties of the maceral group . The density-gradient centrifugation technique was employed to affect maceral group separation. The maximum reflectance method of Ting and Lo was used for estimating the reflectance of very small coal particles. The reflectograms were used to characterize the separated maceral fractions. The density, elemental composition, reflectance, NMR parameters of aromaticity, protonated aromatic carbon content and ƒ_stuggereda^stuggeredH of the maceral groups were compared. Variations in the aromatic structure of the maceral groups are discussed as well as the observation that ƒ_stuggereda and ƒ_stuggereda^stuggeredH change with particle density.     

土地资源单要素计算机解译模式化研究

本文在研究遥感数据特性、典型地物光谱特性和象元几何组构类型的基础上，分析了一物多谱、多物一谱的原因，提出土地资源属性按大类、类、亚类、组、属分类型分等级单要素解译模式；试验区土地资源单要素计算机解译在ＤＴＭ数据的支持下，取得了较好的分类结果。     

The economics of the Swedish individual transferable quota system: Experiences and policy implications

Sweden and other European Union countries are currently carrying out extensive work aimed at improving the marine and freshwater environment. The adaptive management approaches typically used for this require the development of new policy instruments and measures when needed, but also evaluations of instruments and measures already in use or under way. This paper reports on a study of the Swedish individual transferable quota system introduced in 2009 for the pelagic fishery. The new system was motivated mainly by economic arguments and, thus, the need to get incentives right. Despite this, the design of the Swedish system weakened the intended incentive effects in several ways, compared with the foreign systems that served as models. Moreover, the information needed for future evaluations was not collected, even though the need for future evaluations had been expressed explicitly and the data needs for this could be identified at the time that the system was introduced.     

Unravelling the dynamics of a multi-gear fleet – Inputs for fisheries assessment and management under the Common Fisheries Policy

Effective species management requires good knowledge on vessel dynamics, either at a stock basis or through the establishment of multiannual management plans as advisable under the new European Common Fisheries Policy (CFP). Achieving such knowledge on Portuguese multi-gear fisheries is challenging given the large number of species caught and the different management measures applied to potential target species. The latter ranges from no input or output controls to output controls based on individual vessel quotas (IVQ). To provide accurate regional knowledge to the CFP, the dynamics of vessels involved in the trammel net fishery targeting anglerfish (Lophius spp.) was characterised based on onboard sampling data and logbook reports. The selected vessels were very dynamic, and were found to target other species such as hake (Merluccius merluccius), John Dory (Zeus faber) and octopus (Octopus vulgaris). Anglerfish landing trends can be explained by changes in abundance, quota availability and shifts/changes in fishing effort. Overall, the dynamics of these vessels varied with area of exploitation, IVQ value and anglerfish total allowable catch (TAC). These results show the influence of different management systems in the dynamics of vessels and the advantage of an IVQ management system, where fishers can spatially and temporally allocate effort. Results also highlight a fishing effort shift towards unregulated species in face of IVQ or TAC restrictions.     

Catch shares have not led to catch-quota balancing in two North American multispecies trawl fisheries

Catch shares, where annual catch limits are divided among individuals, communities or cooperatives, are a commonly used fisheries management strategy to increase profits and reduce overcapitalization. Usually these quota shares can be sold or leased, which is theorized to allow for greater utilization of fleet-wide quota. However, this catch-quota balancing may not be achieved in multispecies trawl fisheries where it is difficult to selectively target valuable species while avoiding overfished species. Two similar catch-share-managed, multispecies trawl fisheries were compared to evaluate whether catch shares lead to catch-quota balancing. The U.S. West Coast Groundfish fishery has several species with low total allowable catches (TACs) while the Canadian British Columbia Trawl fishery has comparatively higher TACs. Results indicate that the West Coast fishery had a statistically significant decrease in catch-quota ratios from 0.41 in the three years before catch shares to 0.29 in the three years after catch shares. In contrast, the BC fishery experience no statistically significant change in fishery-wide average catch-quota ratios, which were 0.70 in the three years before and 0.62 in the three years after catch shares. In the West Coast fishery, the risk of exceeding quotas for some species may be so high that fishers are unable to achieve high degrees of catch-quota balancing and instead focus on species that can be easily selected with changes in fishing behavior. Multispecies fisheries management has direct tradeoffs between maximizing yield and achieving conservation goals, and these results may highlight the tradeoff between rebuilding overfished species by reducing TACs, and the achievement of catch-quota balancing.     

Spatial conflicts in New Zealand fisheries: The rights of fishers and protection of the marine environment

New Zealand fisheries legislation provides commercial fishing rights to holders of individual transferable quota (ITQ). The settlement of fisheries claims against the Crown by Mäori, New Zealand's indigenous people, brought about the transfer of ITQ holdings to Mäori, and an obligation on the Crown to recognise and provide for indigenous (customary) fishing rights over fishing grounds and other areas that have been of special significance to Mäori. Some types of customary fishing areas exclude commercial fishing and could affect recreational fishing. Fisheries legislation requires that regulatory measures be put in place to avoid, remedy or mitigate the adverse effects of fishing. The Government also aims to protect marine biodiversity by having 10% of New Zealand waters in some form of protection by 2010. The legislative processes for protecting the marine environment and establishing customary fishing areas include assessment of effects on fishing rights. This paper explores the conflicts that arise from legislative obligations to uphold the rights of fishers, to sustain fishstocks and to protect the marine environment. The paper concludes that inconsistent legislative obligations and their disparate processes have led to spatial conflicts and a race for the allocation of space. Legislative obligations need to be integrated to maintain a balance between use of fisheries resources and protection of the marine environment.