A computational scheme to model the geoid by the modified Stokes formula without gravity reductions

In a modern application of Stokesq2q5ehr/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> formula for geoid determination, regional terrestrial gravity is combined with long-wavelength gravity information supplied by an Earth gravity model. Usually, several corrections must be added to gravity to be consistent with Stokesq2q5ehr/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> formula. In contrast, here all such corrections are applied directly to the approximate geoid height determined from the surface gravity anomalies. In this way, a more efficient workload is obtained. As an example, in applications of the direct and first and second indirect topographic effects significant long-wavelength contributions must be considered, all of which are time consuming to compute. By adding all three effects to produce a combined geoid effect, these long-wavelength features largely cancel. The computational scheme, including two least squares modifications of Stokesq2q5ehr/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> formula, is outlined, and the specific advantages of this technique, compared to traditional gravity reduction prior to Stokesq2q5ehr/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> integration, are summarised in the conclusions and final remarks. Acknowledgementsq2q5ehr/xxlarge8194.gif" alt="ensp" align="MIDDLE" BORDER="0">This paper was written whilst the author was a visiting scientist at Curtin University of Technology, Perth, Australia. The hospitality and fruitful discussions with Professor W. Featherstone and his colleagues are gratefully acknowledged.     

Effects of the planned ephesus recreational canal on freshwater–seawater interface in the Selçuk sub-basin, İzmir-Turkey

An artificial water canal opening is planned between the Agean Sea and the historical Ephesus site for the sake of tourism in the Selçuk sub-basin. In order to predict the effects of the planned canal on freshwater–seawater interface and related contamination in the aquifer, 3-D numerical density dependent flow and solute transport simulations were carried out. The simulations included the pre-pumping and pumping periods without a canal and the prediction period in the presence of the canal. Chloride concentration comparisons of the results obtained from the pre-pumping period and the pumping period indicate that the freshwater-seawater interface in the aquifer has progressed inland due to artificial discharge in the sub-basin. Drawdown during the pumping period is about 15 cm. The planned canal opening could further lower the groundwater levels in the area and would change the groundwater flow directions in the first 4 years. Then the levels and flow directions will nearly recover. However, the canal opening could cause further seawater intrusion into the aquifer to the extent that groundwater would be unfit to use for irrigation after the seventh year of the canal opening in the irrigation cooperative II wells area and would be unfit to use for drinking purposes after the tenth year in the municipality wells area located at the south of the cooperative II wells. On the other hand, the cooperative I wells would not be effected by the opening of the canal.     

近代四川气候特征初步分析及展望

本文分析了近代四川气温、旱涝变化的基本特征,并对未来变化趋势进行展望。     

利用车载移动测量数据的建筑物立面建模方法

随着三维空间数据获取能力的提高和人们对三维空间信息需求的提升,城市地区的三维重建成为研究及应用的热点。一方面,建筑物立面包含丰富和直观的细节信息,是建筑物三维建模不可或缺的组成部分;另一方面,车载移动测量是街景级分辨率上高效采集建筑物立面数据的有效途径。但是,目前车载移动测 量系统的数据处理能力难以与其采集能力相匹配,因此,在建筑物三维建模方面仍有巨大潜力和持续的研究价值。本文综合国内外近期研究成果,分析了车载移动测量数据的特点,探讨了利用三维点云和影像序列数 据进行建筑物立面重建及增强的方法,最后总结了现有方法的主要不足及存在的挑战。     

利用全球电离层地图分析芦山地震电离层异常变化

利用全球电离层地图（ g lobalionos p herema p,gim） 提 供 的 垂 直 电 子 含 量（ verticaltotalelectroncon-tent,vtec） 观测值,采用滑动四分位距法分析了芦山地震前后的电离层异常。为了探讨异常现象与地震之间的相关性,进一步确定了震中附近上空 vtec 东 向 及 北 向 梯 度 变 化,并 比 较 分 析 了2008～2012 年 相 同 时间段的 vtec 变化。结果表明,2013年4月18～20日的负异常现象很可能与地震相关。通过分析震中附近电离层赤道异常的变化,发现赤道异常峰值在震前5d内明显减 小,且 峰 值 的 位 置 向 磁 赤 道 方 向 移 动。结 合电离层负异常现象及赤道异常的变化,本 文 认 为 芦 山 地 震 孕 震 区 内 异 常 电 场 可 能 是 引 起 电 离 层 异 常 的 主 要原因之一。     

The demographics of energy and mobility poverty: Assessing equity and justice in Ireland,Mexico, and the United Arab Emirates

Energy and mobility poverty limits people’s choices and opportunities and negatively impinges upon structural economic and social welfare patterns. It also hampers the ability of planners to implement more equitable and just decarbonization pathways. Research has revealed that climate policies have imposed a financial burden on low-income and other vulnerable groups by increasing food and energy prices, leading as well to global inequality. Similarly, researchers have warned that in developing countries, emission mitigation policies could increase poverty rates and even frustrate progress towards universal access to clean energy. This research explores whether low-income social groups experience a 'double energy vulnerability', a situation that simultaneously positions people at heightened risk of transport and energy poverty. We investigate this 'double vulnerability' through original data collection via three nationally representative surveys of Mexico (N = 1,205), the United Arab Emirates (N = 1,141), Ireland and Northern Ireland (N = 1,860). We draw from this original data to elaborate on the sociodemographic attributes, expenditure and behaviour emerging from energy and transport use, focusing on themes such as equity, behaviour and vulnerability. We propose energy and transport poverty indexes that allow us to summarize the key contributing factors to energy and transport poverty in the countries studied and uncover a strong correlation between these two salient forms of poverty. Our results suggest that energy and transport poverty are common issues regardless of the very different national, and even sub-national, contexts. We conclude that energy and transport poverty requires target policy interventions suitable for all segments of society, thus enabling contextually-tailored, just energy transitions.