长江三角洲地区水和热通量的时空变化特征及影响因子

文中利用改进的K B模式和牛顿扩散方法及 196 1年以来的长江三角洲 (2 8～ 33°N ,118～ 12 3°E)地区的 4 8个测站的常规气象资料 ,估计了该地区近 4 0a来的蒸散量和感热通量。结合该地区的气温、太阳辐射等气候资料和 196 0年以来该区域土地资源利用变化等有关信息对该地区的潜热通量和感热通量的时 空间变化特征及其可能成因进行了综合分析。结果认为该地区自 2 0世纪 70年代开始平均蒸散量有逐渐减小的趋势 ,与 1980年相比 ,1998年区域年平均蒸散量减小了 2 4mm。区域平均感热通量与蒸散量相比在此期间变化并不明显。通过对该地区的云量、太阳辐射及土地利用变化资料分析认为 ,造成该地区平均蒸散量减少趋势的的原因之一是用于蒸发的能量即太阳辐射的减少 ,而造成太阳辐射减少的可能原因为云量及大气透明度的变化所至 ;原因之二是该地区地表覆盖条件的改变。近 2 0a来 ,该地区的水田、旱地及水域面积占总面积的比率分别减少 1.35 3% ,4 .4 4 2 %和2 .5 97% ,而城镇建设、工矿及其它建设用地面积则增加 3.345 %。耕地及水面的减小和城镇及建设用地面积的增加从整体上使区域平均蒸发量减少。     

乾安地区盐碱地显热通量的测量

文中给出了用大孔径闪烁仪在 2 0 0 0年生长季观测到的盐碱地区显热通量的主要结果 ,并初步计算了当地的水热平衡状况。结果表明 :乾安盐碱地区显热通量占净辐射量的百分比在干旱、非生长季达到 6 5 % ,在多雨、植被生长季仅为 11% ;显热通量因降水而明显降低 ,幅度与降水强度有关 ,反映了当地的气候和土壤特征。文中还把LAS的测量结果与传统的梯度法作了比较 ,结果基本一致。     

中国西北部盆地岩石热导率和生热率特征

本文根据大量实测数据,首次系统地报道了中国西北地区塔里木盆地、准噶尔盆地和柴达木盆地内的岩石热导率、岩石放射性生热率数据及其分布特征.对600多个岩石热导率和100多个实测岩石生热率的统计分析表明,沉积盆地中岩石的热物理性质与其岩性、埋藏深度和地层时代密切相关.随深度和地层时代的加大,岩石热导率增大;塔里木盆地的岩石热导率的总体平均值最大,而柴达木盆地的最小.岩石生热率在上地壳的分布是随深度的增加而减小的,但在沉积盆地的深度范围内几乎不变,其分布是均匀的,仅不同岩性的生热率差别较大.估算的岩石放射性生热产生的热量可以占到盆地地表热流的25%～45%.因此,岩石热物理性质的参数不仅与盆地的地温分布和大地热流特征密切相关,还可以为该地区盆地热历史恢复及深部地球物理的研究提供有效的参数和边界条件.     

新疆东昆仑木孜塔格蛇绿混杂岩中发现富Nb玄武岩

富Nb 玄武岩以相对高的TiO2 含量、低的LILE/HFSE和LREE/HFSE比值以及(La/Nb)MN＜2为特征,是岛弧环境的典型产物。首次报道发现于新疆东昆仑木孜塔格蛇绿混杂岩中的富Nb玄武岩,并分析了它们的典型地球化学特征和构造环境,表明了它们形成在岛弧环境。     

The fall and rise of metropolitan government in Copenhagen

In this paper it is argued that the re-establishment of a metropolitan government in the Greater Copenhagen Area in 2000 (Greater Copenhagen Authority) is not to be seen as a return to the kind of regional, coordinative authority (Greater Copenhagen Council) that was abolished in the Thatcherite climate of the 1980s. Throughout the 1980s and 1990s new forms of urban governance, entrepreneurialism and a higher national priority to the capital region were introduced, which changed the conditions under which the new metropolitan government is operating. This `contextualization' of the analysis of the two generations of metropolitan government points to the fact that typologies of metropolitan government, such as the one put forward by Sharpe (1995), often lacks analytical cogency. This revised version was published online in August 2006 with corrections to the Cover Date.     

Milan: The city of constant renewal

Traditional models of urban development are no longer adequate to describe current metropolitan transformations. These are now at the centre of a debate concerning management and administration. In Italy, delays in resolving problems of urban and metropolitan government, despite the legal framework provided by Law 142/90, have weighed heavily on the larger urban areas of the country: Rome, Naples, Milan, which have not been able to tackle the issue of metropolitan government. Recent legislation, while not providing a pre-defined institutional solution, allows separate administrative districts to collectively establish metropolitan institutions of `variable geometry'. The Milan urban area is not one city, but a system of mutually-dependent cities, linked to each other and the rest of the world by a transport network still requiring much investment. The vitality of its economic structure (especially its small firms) is held back by seriously inadequate infrastructure and low external economic efficiency. The provincial capital may boast `historic centrality' but the most interesting potential for development is to be found on the periphery and in the administrative districts immediately surrounding it, in the recovery of derelict industrial areas and dormitory towns established in the 1950s and 1960s, especially to the north. Recovery of derelict areas, green areas, and better transport links within the urban area and with the outside world are the key elements in the reorganization of `Greater Milan'. In this situation of rapid transformation the most appropriate political strategies involve negotiated planning. This revised version was published online in August 2006 with corrections to the Cover Date.     

人工值守台数字化地震仪标定原理

推导了人工台数字化地震仪的分段标定公式，提出数字化记录系统的微分近似标定和拾震器阻尼衰减法标定的方法，并提供了不同短周期地震仪与数字化地震仪并行的藕合方式和标定计算公式。     

Recycling in the Puerto Rican mantle wedge, Greater Antilles Island Arc

Abstract The initial volcanic phase of Cretaceous island arc strata in central Puerto Rico, at the eastern end of the extinct Greater Antilles Arc, comprises a 6‐km thick pile of lava and volcanic breccia (Río Majada Group). Preserved within the sequence is a conspicuous shift in absolute abundances of the more incompatible elements, including Th, Nb, and the light rare earth elements (LREE: La, Ce, Pr and Nd). The compositional shift is marked by a decrease in La/Sm from averages of 2.11 in the lowest third of the pile (Formation A) to 1.48 at the top (Formation C), and by a distinctive flattening of LREE segments of chondrite‐normalized REE patterns. i⁸⁷Sr/⁸⁶Sr and ?_Nd average about 0.7035 and 8.2, respectively, in early Formation A basalts. These ranges normally overlap samples from later Formations B and C. Isotope compositions of the latter group are more variable, however, and several samples are considerably more radiogenic than Formation A basalts, such that i⁸⁷Sr/⁸⁶Sr averages almost 0.7042 while ?_Nd‐values decrease to 7.5 in Formation B and C basalts. Theoretical models of non‐modal melting processes in both amphibole peridotite and spinel lherzolite sources provide insight into the origin of depleted Th, Nb, and LREE abundances in Puerto Rican basalts. Low Nb concentrations less than normal mid‐oceanic ridge basalts in Formation A basalts indicate the wedge was slightly depleted by low‐volume decompression fusion due to induced convection in the back‐arc region prior to entry of the source into the arc melting zone. However, depleted patterns in Formation C basalts cannot be generated by relatively greater degrees of decompression fusion in the back‐arc, because addition of the La‐enriched slab‐derived component to more depleted source material invariably produces elevated rather than decreased La/Sm. Refluxing of Formation A harzburgitic residua is similarly precluded. In contrast, the observed patterns are readily reproduced by multistage melting models involving hybridized sources containing normal Formation A lherzolite source material blended with recycled, unrefluxed harzburgite residua. Successful models require hybrid sources containing large volumes of recycled harzburgite (up to 50%) during generation of Formation C basalts. Slightly elevated radiometric Sr and Nd isotopes in a few flows from Formation C are attributed to partial refluxing of the hybrid sources within the wedge.     

探测大城市活断层的地球物理方法

简要地介绍了开展大城市地震活断层探测的意义及世界各国开展活断层探测的基本情况。城市及邻近地区地震活断层引起的直下型地震 ,将会给大城市造成巨大的地震灾害。准确地探测出大城市的活断层分布 ,采取有效措施 ,可大大降低地震时的损失。文中重点介绍了开展地震活断层探测的地球物理方法的类型和主要特点 ,在区域探查与初步鉴定阶段、详细探测与精确定位阶段、孕震构造探测阶段可能涉及到的各种地球物理探测方法、适用范围及所能解决的主要问题     

乌鲁木齐区域数字遥测台网各子台背景噪声分析

选取乌鲁木齐区域数字遥测台网中 1 1个子台的背景噪声数字记录 ,计算并分析其背景噪声地动速度均方根值 RMS、有效测量动态范围以及噪声功率谱 ,最后确定出各台址背景噪声相对集中的频段