基于30m归一化植被指数的近30年三江源高寒草地植被时空变化及气候影响研究（英文）

植被长期变化及其对气候变化的响应一直是生态学研究的热点。本研究应用前期基于Landsat数据融合得到的青藏高原三江源区1990–2018年近30年30 m空间分辨率归一化植被指数(NDVI),以Theil-Sen中值法和线性回归,分析了近30年高寒草地时空变化及气候变化影响。结果表明：(1)研究区NDVI呈从东南到西北逐渐降低的空间格局,全区平均NDVI为0.39,其中澜沧江源NDVI最高(0.43),其次是黄河源(0.38)和长江源(0.23)。(2)研究期间,全区NDVI以0.0031yr^–1的速率呈上升趋势(R²=0.62,P<0.01),后期(2005–2018年)增长速度为0.00649 yr^–1(R²=0.71,P<0.01),是前期(1990–2005年间)速率0.00284 yr^–1(R²=0.31,P<0.01)的近2.3倍,说明后期(2005–2018年)植被变绿加速,且不同流域间增速在2.3至63倍间。(3)NDVI...     

兰州市南北两山植被覆盖度动态变化遥感监测

本文基于植被指数(NDVI)和植被覆盖度像元分解模型,建立了兰州市南北两山植被覆盖度遥感定量模型,在此基础上研究了兰州市南北两山1991年和2006年两个时期的植被覆盖度动态变化,结果表明:1991-2006年兰州市南北两山绿化工程区植被覆盖度总体呈上升趋势,低植被覆盖度面积减小,中高和高植被覆盖度面积增加,其中七里河工程区植被覆盖度变化最为明显,绿化效果较好,安宁工程区绿化效果相对较差,结果可为兰州市南北两山绿化工程提供科学依据。     

ISO2002: an analytical stochastic model of multi-difference GPS carrier-phase data

The differencing technique is useful in global positioning system (GPS) positioning when two or more GPS receivers collect simultaneous observables from common satellites at each epoch, and all carrier-phase observables have the same normal distribution. An analytical probability distribution of the single-, double-, triple- and multi-difference GPS observables is obtained. This analytical model, called ISO2002, has a good matrix structure, in which I indicates the number of receivers, S indicates the number of observed satellites, and O indicates the number of epochs. The variance–covariance matrix can be expressed as the Kronecker product of several small matrices, so its inverse is equal to the Kronecker product of the inverses of these sub-matrices. Moreover, these small matrices are circulant or symmetric diagonal Toeplitz matrices, so their inverses have analytical solutions. The analytical model ISO2002 proposed to compute the inverse variance–covariance matrix is shown to be very effective.     

县域经济和社会同人口、资源、环境协调发展研究

县域经济和社会同人口、资源、环境协调发展,是我国区域人口、资源、环境与发展研究的最基层地域单元。它对当前各地区经济和社会的持续、稳定、协调发展,以及发挥各地区的综合优势和产业结构的调整具有重要的理论和实践意义。本文探讨了县域协调发展的目标、研究的指导思想和研究方法。     

Response of remotely sensed Normalized Difference Water Deviation Index to the 2006 Drought of eastern Sichuan Basin

One of the most serious droughts in last century occurred in eastern Sichuan Basin in the summer of 2006 (hereinafter called the Drought). The response of Moderate Resolution Imaging Spectroradiometer (MODIS, boarding on NASA satellites of Terra and Aqua) to the Drought was analyzed in order to reach one practicable monitoring solution for regional soil moisture. Temporal process and spatial extension of the Drought were firstly estimated with ground meteorological and hydrological observations. Then, for the whole region of Sichuan and Chongqing, the remotely sensed Normalized Difference Water In- dex (NDWI) for the summers of 2001―2006 were calculated based on 8-day composite MODIS products, which were further used to construct a new water index (Normalized Difference Water Deviation Index, NDWDI) to examine the sensitivity of remote sensing in the Drought. The study showed that the NDWDI is more sensitive to regional drought than other absolute-soil-moisture-based indices. With the new index, the study extracted the spatial-temporal characteristics of the 2006 Drought, and explored its developing and withdrawing processes, which agreed with related statistics. Compared with ground method of drought observation, the NDWDI-based remote sensing solution of this paper is more pref- erable and practicable in that the local soil properties of water consumption and supply are implicitly taken into account, and the spatial representativity limit of ground observation is circumvented to a degree as satellite remotely senses the earth surface in a way of two-dimensional pixel matrix. So, the NDWDI-based method can be used to monitor regional soil water stress situation more practically and efficiently.     

The effectiveness of the ISM Code: A qualitative enquiry

Studies conducted to determine the efficacy of the ISM Code in the past include investigations of the trends of accident numbers and insurance claims and users' perceptions. None of these, however, could produce a definitive conclusion. This is because both the use of safety outcome as well as the use of perception have inherent problems and are not reliable. This paper takes a different approach. It draws on wider research on management of workplace health and safety to ascertain whether or not employment and social conditions that support effective implementation of self-regulation are present in the maritime context. The findings reveal a considerable disparity between managers' and seafarers' understanding of the use of the Code resulting in a wide gap between its intended purpose and practice. The analysis shows that the critical factor is the lack of seafarers' participation in management of workplace health and safety. The underlying causal factors for such lack of participation were located in seafarers' poor employment condition and low-trust relationship with their managers.     

Many roads to Paris: Explaining urban climate action in 885 European cities

Research on urban climate action has identified a broad range of potential factors explaining why and how local governments decide to tackle climate change. However, empirical evidence linking such factors in order to explain actual urban climate action has so far been mixed. To address this roadblock, our paper relies on a novel approach, postulating that different configurations of factors may lead to the same outcome (“equifinality”), through a qualitative comparative analysis (QCA). It is based on an available data set of local climate mitigation plans in 885 European cities. We find that urban climate action is systematically associated with four qualitatively different configurations of factors, each with its own consistent narrative (“networker cities”, “green cities”, “lighthouse cities”, “fundraising cities”). Crucially, some factors play a positive role in some configurations, a negative in others, and no role in further configurations (e.g., whether a city is located in a country with supportive national climate policies). This confirms that there is no single explanation for urban climate action. Achieving greater robustness in empirical research about urban climate action may thus require a shift, both conceptual and methodological, to the interactions between factors, allowing for different explanations in different contexts.     

利用到时差分布图方法进行近场地表震源定位

近场震源的高精度定位在工程建设与军事应用等方面意义重大且应用广泛,如炮弹落点定位或车辆追踪等.定位过程面临速度结构未知、高分辨率要求等问题,传统的震源定位方法有一定的局限性.本文将超声波检测中的时差分布图（Delta T Mapping,简称DTM）方法首次成功引入近场震源定位问题中.DTM定位法首先建立一个测区的到时差模型,然后基于此模型对新的震源进行定位.有两种建立模型的方法,（1）网格搜索法：对原有模型进行线性插值,得到更高分辨率的到时差分布模型;（2）统计定位法：利用高斯过程回归建立到时差数据与位置坐标之间的映射关系.本文在北京某郊区进行了炸点定位实验,在140 m×90 m的测试区域内,定位误差为0.5~5.1 m.结果表明,DTM方法是一种可靠、高精度、具有近实时性的近场震源定位方法.进一步利用接收点、源点互换,在获得高精度DTM同时,可大幅降低标定与数据分析成本.结合震源扫描法具有解决多目标定位问题的潜力.

     

Change trends in urban freight delivery: A qualitative inquiry

In this paper we present the findings of a qualitative investigation of change trends in urban freight deliveries. The empirical material was gathered with urban freight (courier) company managers and drivers in Aotearoa New Zealand. It presents personal accounts of the everyday lived experiences of those intimately involved in the delivery of goods within the urban environment. Twenty-five interviews were conducted across four urban centres between June and September 2015. We use the four elements of the Energy Cultures Framework to explore what urban freight managers and drivers ‘have’, ‘do’ and ‘think’, and the pressures of an external context. Four interrelated themes are presented. 1. Online shopping and home deliveries, 2. Tracking and transparency, 3. New technologies, and 4. Meeting (changing) expectations, with evidence provided by way of verbatim quotations. The ‘mobility cultures’ concept is used to explore the relationships between the four themes, and to identify the key change trends that may affect the ability of the freight industry to contribute to a low-carbon transport transition. We conclude by signalling some policy implications and future research directions.