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981.
Yong Zhang Tao Yang Junbo Zhang Baoyi Lv Xiangsheng Cheng Yin Fang 《中国海洋大学学报(英文版)》2020,19(3):633-642
The Sanchi oil tanker collision in the East China Sea on January 6th, 2018 has caused worldwide attention due to its uniqueness. A considerable amount of h 相似文献
982.
983.
The interannual variations of rainfall over southwest China (SWC) during spring and
its relationship with sea surface temperature anomalies (SSTAs) in the Pacific are analyzed,
based on monthly mean precipitation data from 26 stations in SWC between 1961 and 2010,
NCEP/NCAR re-analysis data, and Hadley global SST data. Sensitivity tests are conducted to
assess the response of precipitation in SWC to SSTAs over two key oceanic domains, using the
global atmospheric circulation model ECHAM5. The interannual variation of rainfall over SWC in
spring is very significant. There are strong negative (positive) correlation coefficients
between the anomalous precipitation over SWC and SSTAs over the equatorial central Pacific
(the mid-latitude Pacific) during spring. Numerical simulations show that local rainfall in
the northwest of the equatorial central Pacific is suppressed, and a subtropical anticyclone
circulation anomaly is produced, while a cyclonic circulation anomaly in the mid-latitude
western Pacific occurs, when the equatorial Pacific SSTAs are in a cold phase in spring.
Anomalous northerly winds appear in the northeastern part of SWC in the lower troposphere.
Precipitation increases over the Maritime Continent of the western equatorial Pacific, while a
cyclonic circulation anomaly appears in the northwest of the western equatorial Pacific. A
trough over the Bay of Bengal enhances the southerly flow in the south of SWC. The trough also
enhances the transport of moisture to SWC. The warm moisture intersects with anomalous cold
air over the northeast of SWC, and so precipitation increases during spring. On the
interannual time scale, the impacts of the mid-latitude Pacific SSTAs on rainfall in SWC
during spring are not significant, because the mid-latitude Pacific SSTAs are affected by the
equatorial central Pacific SSTAs; that is, the mid-latitude Pacific SSTAs are a feedback to
the circulation anomaly caused by the equatorial central Pacific SSTAs. 相似文献
984.
In the contemporary American urban renaissance, formerly fringe efforts to produce place, conducted by longtime residents and “urban pioneers” alike, now shape mainstream urbanism. Gardening and bicycling are constitutive of contemporary excitement about the city, representing the reinvigoration of the urban neighborhood following the depredations of suburbanization. This paper draws on research in California cities to offer a sympathetic critique of these leading edges of progressive urbanism, arguing that advocates’ overwhelming focus on the local creates a scalar mismatch between the horizon of political action and the problems they hope to address. Even as supporters of gardening and cycling understand themselves as implicitly allied with struggles for the right to the city, their work to produce local space is often blind to, and even complicit in, racialized dynamics of accumulation and exclusion that organize metropolises. The result is a progressive urbanism largely disconnected from broader left struggles for spatial justice. 相似文献
985.
In this paper, we present a reflexive examination of how and why we, an academic and a practitioner, arrive at different evaluations of collaborative progress in natural resource management. We situate this examination in our long-standing involvement in designing, adaptively managing, and participating in the Uncompahgre Plateau collaborative forest restoration project in western Colorado, USA. Drawing on the concept of “positionality” in qualitative social science research, we disclose our respective motivations, assumptions, roles, and power relative to the collaborative process. The differences in evaluating collaborative progress stem from our respective professional positionality. For the academic, the guiding interest was to test theory and promote success for his applied research institute; for the practitioner, the motivation was to build trust to allow her field staff the flexibility to implement management actions and demonstrate effectiveness as an agency line officer. These epistemological differences draw attention to the importance of transdisciplinary approaches to producing knowledge from shared practice, starting with efforts to explicitly disclose and honor differing interests, assumptions, and frames of reference stemming from each party’s personal and professional biographies and institutional norms. This reflexivity is essential to advancing knowledge about collaboration in natural resource management. 相似文献
986.
Christopher J. Wynveen Ingrid E. Schneider Stuart Cottrell Arne Arnberger Alexander C. Schlueter Eick Von Ruschkowski 《社会与自然资源》2017,30(11):1389-1403
Researchers often measure human–place bonds via place attachment scales across a variety of settings. However, scale use does not always include an evaluation of the scales’ psychometric properties, especially in multisite studies. Failure to consider a place attachment scale’s measurement properties makes both validity and reliability assumptions and may lead to improper data interpretation. Hence, this investigation assessed a place attachment scale across three sites via data collected on site in natural resource protected areas in Colorado, Minnesota, and Germany. A series of confirmatory factor analyses assessed the hypothesized two-dimensional (i.e., place identity and place dependence) model, Cronbach’s alphas calculated a measure of internal consistency, and a multigroup procedure cross-validated the scale. Some items did not load on the hypothesized dimension and the pattern of factor loadings was not equivalent across settings, suggesting assessment of place attachment scales may be necessary when used in new contexts. 相似文献
987.
Philip A. Allen Nikolaos A. Michael Mitchall D’Arcy Duna C. Roda‐Boluda Alexander C. Whittaker Robert A. Duller John J. Armitage 《Basin Research》2017,29(2):180-202
Sediment is fractionated by size during its cascade from source to sink in sediment routing systems. It is anticipated, therefore, that the grain size distribution of sediment will undergo down‐system changes as a result of fluvial sorting processes and selective deposition. We assess this hypothesis by comparing grain size statistical properties of samples from within the erosional source region with those that have undergone different amounts of transport. A truncated Pareto distribution describes well the coarser half of the clast size distribution of regolith, coarse channel bed sediment and proximal debris flows (particularly their levees), as well as the coarser half of the clast size distribution of gravels that have undergone considerable amounts of transport in rivers. The Pareto shape parameter a evolves in response to mobilization, sediment transport and, importantly, the selective extraction of particles from the surface flow to build underlying stratigraphy. A goodness of fit statistic, the Kolmogorov–Smirnov vertical difference, illustrates the closeness of the observed clast size distributions to the Pareto, Weibull and log‐normal models as a function of distance from the depositional apex. The goodness of fit of the particle size distribution of regolith varies with bedrock geology. Bedload sediment at catchment outlets is fitted well by the log‐normal and truncated Pareto models, whereas the exponential Weibull model provides a less good fit. In the Eocene Escanilla palaeo‐sediment routing system of the south‐central Pyrenees, the log‐normal and truncated Pareto models provide excellent fits for distances of up to 80 km from the depositional apex, whereas the Weibull fit progressively worsens with increasing transport distance. A similar trend is found in the Miocene–Pliocene gravels of the Nebraskan Great Plains over a distance of >300 km. Despite the large fractionation in mean grain size and gravel percentage from source region to depositional sink, particle size distributions therefore appear to maintain log‐normality over a wide range of transport distance. Use of statistical models enables down‐system fractionation of sediment released from source regions to be better understood and predicted and is a potentially valuable tool in source‐to‐sink approaches to basin analysis. 相似文献
988.
精准扶贫视角下中国东北农村贫困地域性特征及成因 总被引:7,自引:4,他引:3
基于结构性问卷,采用入户访谈及问卷调查的方法,解析中国东北地区农村贫困空间格局与地域性特征,并对区域内部典型农村贫困区贫困问题的形成机制进行探讨与解构。研究认为: 东北地区农村贫困人口与贫困县集中分布在大兴安岭南麓和黑、吉、辽三省与内蒙古东部交界地区以及中俄、中朝边境地区,形成东、西两大片区,西部片区呈带状自北向南延伸,东部片区内存在两个团块状贫困人口集聚区,整体表现出“大集聚,小分散”的空间分布特征。② 区域内部存在5个农村贫困高发区,分别为中俄北部边境贫困高发区、中俄东部边境贫困高发区、松嫩平原贫困高发区、西部贫困高发区、中朝边境贫困高发区;农村贫困发生率“北高南低,西低东高”的特征明显。③ 农村贫困群体以中老年人为主,文化水平整体较低,吃穿与医疗保障问题突出;罹患疾病以及耕地不足、耕地利用率低是导致东北地区农村贫困的主因,发展现代农业和外出务工是消除贫困的重要途径。 ④ 区域内部存在西部农牧交错区、东部边境山地朝鲜族聚居区、东部平原与丘陵过渡区三大典型农村贫困区,西部农牧交错区农村贫困问题的产生主要受农业生产结构单一、农产品市场价格下行、农户自身思想认识落后、基础设施建设滞后、区域自然生态条件不利等多种因素的协同影响;东部边境山地朝鲜族聚居区农村贫困问题主要由劳动年龄人口的持续性外流所引发的系列效应导致;东部平原与丘陵过渡区农村贫困问题的出现主要受地理位置偏远、地形复杂导致自然灾害多发、耕地资源不足的影响。 相似文献
989.
990.