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81.
Changes in aridity in response to the global warming hiatus   总被引:2,自引:0,他引:2       下载免费PDF全文
The global warming slowdown or warming hiatus, began around the year 2000 and has persisted for nearly 15 years. Most studies have focused on the interpretation of the hiatus in temperature. In this study, changes in a global aridity index (AI) were analyzed by using a newly developed dynamical adjustment method that can successfully identify and separate dynamically induced and radiatively forced aridity changes in the raw data. The AI and Palmer Drought Severity Index produced a wetting zone over the mid-to-high latitudes of the Northern Hemisphere in recent decades. The dynamical adjustment analysis suggested that this wetting zone occurred in response to the global warming hiatus. The dynamically induced AI (DAI) played a major role in the AI changes during the hiatus period, and its relationships with the North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), and Atlantic Multi-decadal Oscillation (AMO) also indicated that different phases of the NAO, PDO, and AMO contributed to different performances of the DAI over the Northern Hemisphere. Although the aridity wetting over the mid-to-high latitudes may relieve long-term drying in certain regions, the hiatus is temporary, and so is the relief. Accelerated global warming will return when the NAO, PDO, and AMO revert to their opposite phases in the future, and the wetting zone is likely to disappear.  相似文献   
82.
徐州都市圈工业结构转型及其影响效应分析   总被引:1,自引:0,他引:1  
在GIS空间分析技术支持下,采用工业结构转型相关指数方法,深入分析了2000~2012年徐州都市圈工业结构转型的时空演化特征及其对区域发展的影响效应。发现:近10 a来徐州都市圈工业转型速度、高级化呈较快提升趋势,且与工业经济增长明显相关,但合理化程度下降;竞争优势行业和主导产业均呈向资本技术密集型行业演化趋势,但主导产业的支撑作用有待增强;空间上呈现先集聚后扩散趋势,不同行业空间集聚程度各异,形成了沿东陇海工业集聚发展轴;工业专业化分工呈现以徐州为核心向外技术水平下降的圈层式垂直分工格局;工业高级化和区域工业占有率对经济增长促进作用显著,而对能源消耗和工业SO2排放抑制作用明显,但不同尺度区域影响存在差异。  相似文献   
83.
This study examines the impact of atmospheric and oceanic conditions during May–August of 2004 and 2010 on the frequency and genesis location of tropical cyclones over the western North Pacific. Using the WRF model, four numerical experiments were carried out based on different atmospheric conditions and SST forcing. The numerical experiments indicated that changes in atmospheric and oceanic conditions greatly affect tropical cyclone activity, and the roles of atmospheric conditions are slightly greater than oceanic conditions. Specifically, the total number of tropical cyclones was found to be mostly affected by atmospheric conditions, while the distribution of tropical cyclone genesis locations was mainly related to oceanic conditions, especially the distribution of SST. In 2010, a warmer SST occurred west of 140°E, with a colder SST east of 140°E. On the one hand, the easterly flow was enhanced through the effect of the increase in the zonal SST gradient.The strengthened easterly flow led to an anomalous boundary layer divergence over the region to the east of 140°E, which suppressed the formation of tropical cyclones over this region. On the other hand, the colder SST over the region to the east of 140°E led to a colder low-level air temperature, which resulted in decreased CAPE and static instability energy. The decrease in thermodynamic energy restricted the generation of tropical cyclones over the same region.  相似文献   
84.
脆弱性分析是可持续发展的重要研究内容。从敏感性与应对能力两方面构建经济系统脆弱性指标体系,运用客观赋权、集对分析、障碍度评价公式等方法对2011年中国沿海地区经济系统的脆弱性空间分异特征、机理、障碍因素进行评价分析,结果表明:1从整体看,中国沿海地区经济系统脆弱性普遍较高且类型空间分布整体分散、部分连片集中,空间差异性显著,其中华南、东北沿海地区的经济脆弱性明显高于华东、华北沿海地区,呈现出较高脆弱与高脆弱特征。2从分区看,中等脆弱地区集中在京津、江浙和广东等经济较为发达的地区,该地区具有高敏感性与高应对性的特征;辽宁、河北、福建、广西和海南等地区的经济系统脆弱性较高,主要特征表现为高敏感性和较低的应对能力。3通过对沿海各地区经济系统脆弱性障碍因子的分析,提出中国沿海地区11省、市、自治区经济系统可持续发展建议。  相似文献   
85.
西藏水土流失敏感性评价及其空间分异规律   总被引:7,自引:0,他引:7  
Based on Universal Soil Loss Equation and methods of mathematics model and GIS analysis, this study classified influence of precipitation, soil, topography and vegetation upon sensitivity of soil erosion into five different degrees which are extreme sensitivity, quite sensitivity, sensitivity, less sensitivity and no sensitivity. Assessment map of each factor was generated separately. Integrated assessment map of sensitivity of soil erosion has also been drawn by overlapping function with Arcinfo. Furthermore, the study analyzed distribution characteristics and spatial difference of sensitivity of soil erosion under special plateau environment of Tibet. According to sensitivity degree, some important controlling regions was confirmed so that departments of water conservancy, traffic management and agriculture could make scientific and reasonable decisions for their respective subject planning.  相似文献   
86.
Despite continuing efforts to upgrade the urban storm sewer system since the late 1950s, the City of Shanghai is still vulnerable to persistent rainstorm waterlogging due to excess surface runoff and sewer surcharge, which frequently cause significant damage to buildings and disruption to traffic. Rapid urbanization and associated land cover changes are the major factors contributing to waterlogging. However, it is unclear to what extent changes in rainfall variability over the past few decades are also involved. This paper investigates the combined impacts of land use and land cover change, storm sewer development, and long-term variations in precipitation. Evidence of persistent waterlogging is presented first. We then give an account of land surface modifications during the process of urbanization and the development of the city??s urban storm sewer system. Statistical analysis suggests that the increase in runoff coefficient due to conversion of lands from agricultural to industrial, commercial, and residential uses is a major factor driving greater waterlogging risk. In particular, historical analysis of aerial photographs reveals the rate and extent of modification to river networks in the past few decades. The natural drainage network has shrunk by 270?km, significantly reducing the city??s capacity to transport excess surface flow. In line with other studies, we find no significant overall trends in annual rainfall totals (at Baoshan and Xujiahui). However, seasonal and monthly rainfall intensities have increased. At the daily scale, we find that compared to pre-1980s: (i) there has been an increase in the number of wet days with precipitation exceeding 25?mm (Heavy Rainfall) and decrease in those below 25?mm and (ii) the number of consecutive wet days with precipitation maximum and average exceeding the threshold known to cause waterlogging shows an increasing trend. Since rainfall intensity is expected to increase under climate change, this could further compound the impacts of land use changes and place even greater pressure on the existing storm sewer system.  相似文献   
87.
福建省上杭县罗卜岭斑岩铜钼矿床构造控矿规律研究   总被引:6,自引:0,他引:6  
赖晓丹  祁进平 《地质学报》2014,88(10):1904-1916
罗卜岭铜(钼)矿区位于紫金山矿田的东北部,是与晚中生代花岗闪长斑岩体有关的隐伏斑岩型铜钼矿床;主要斑岩矿体产于绿泥石化-绢英岩化和(弱)钾化-绢英岩化带中,矿石矿物组合为黄铜矿+辉钼矿;少量过渡类型矿体产于高级泥化带中,矿石矿物组合为蓝辉铜矿+铜蓝+辉钼矿。罗卜岭矿区地表露头含矿裂隙的统计结果显示,罗卜岭成矿晚期的含矿裂隙具有明显的方向性。远离斑岩体的含矿裂隙与其附近的区域构造方位或侵入体走向相近,表明受到北东向区域构造活动控制;而斑岩体西侧露头附近的含矿裂隙呈放射状,主要受到斑岩体侵入作用的影响。深部隐伏矿体则受到区域断裂和花岗闪长(斑)岩侵入体的共同控制,具体表现为:垂向上,以隐伏似斑状花岗闪长岩为中心,由深至浅,矿体铜钼品位比值依次变大,显示了Mo\Cu-Mo\Cu(Mo)的元素垂向分带;平面上,铜、钼元素沿着北东向、北西向断裂和岩体接触带附近有明显富集;斑岩型铜钼矿体主要产于似斑状花岗闪长岩外接触带的花岗闪长斑岩中,形态和产状受到区域北东向断裂或岩体接触带构造影响;蓝辉铜矿体主要产于罗卜岭花岗闪长斑岩外接触带的花岗闪长岩体内,形态和产状受接触带控制。区域构造和斑岩侵入体对斑岩型铜钼矿化有不同的影响,浅部铜、钼矿化受区域断裂构造控制作用明显,而深部矿体主要受花岗闪长(斑)岩体和断裂构造共同控制。区域上北东向背斜构造和北东、北西向断裂构造控制了花岗闪长质侵入岩体的侵位,矿区尺度的断裂构造对斑岩体的就位和成矿作用有一定的影响,罗卜岭花岗闪长斑岩体及其接触带则直接控制了斑岩型矿体的产出,这一规律对紫金山矿田深部和外围隐伏斑岩型矿体的勘查工作具有重要的参考意义。  相似文献   
88.
在全球变化研究中,高分辨率、网格化的气候数据作为环境因子是地学模型和气模型等相关研究的重要参数.本文以黑龙江省小兴安岭地区为研究对象,采用ANUSPLIN空间插值方法,利用该区域69个地面降水月值0.5°×0.5°格点和1 km空间分辨率DEM,对逐月降水进行了空间插值,使用广义交叉验证方法和多个评估指标进行了误差分析和精度评价,进一步分析了2020年小兴安岭地区降水月值的时空特征.结果表明:TVTPS4模型具有最优插值精度和区域适用性;降水具有阶段性和季节性,以及地域分布差异特征.本研究成果可为复杂地形地貌的气象要素精细化研究,以及区域可持续发展科学决策提供参考.  相似文献   
89.
The temporal dynamics of the biomass, as well as the carbon (C), nitrogen (N), phosphorus (P) concentrations and accumulation contents, in aboveand below-ground vegetation components were determined in the alpine steppe vegetation of Northern Tibet during the growing season of 2010. The highest levels of total biomass (311.68 g m−2), total C (115.95 g m−2), total N (2.60 g m−2), and total P (0.90 g m−2) accumulation contents were obtained in August in 2010. Further, biomass and nutrient stocks in the below-ground components were higher than those of the above-ground components. The dominant species viz., Stipa purpurea and Carex moorcrofti had lower biomass and C, N, P accumulations than the companion species which including Oxytropis. spp., Artemisia capillaris Thunb., Aster tataricus L., and so on.  相似文献   
90.
2009年3月中旬新疆融雪型洪水气象成因分析   总被引:3,自引:0,他引:3  
田华  杨晓丹  张国平  赵琳娜  王志  赵鲁强 《气象》2011,37(5):590-598
利用1950-2006年的新疆融雪型洪水灾情资料对新疆地区融雪型洪水发生特点进行了分析.结果表明:新疆地区融雪型洪水多发生在天山北坡,特别是伊犁河谷和塔城地区是融雪型洪水的多发区域.3月中旬到4月上旬为融雪型洪水的多发时期.在此基础上,从气候背景、天气诊断分析等方面对2009年3月中旬融雪型洪水的气象成因进行了分析和研究,得出:2009年2月降水明显偏多为3月中旬融雪洪水的发生提供了基础条件,而3月中旬冷空气过后气温持续迅速回升是此次融雪洪水发生的主要气象因素.持续迅速升温过程中,平均气温由负转正、最高气温高于5℃以及暖平流中心出现时间对融雪型洪水预报具有指示意义.  相似文献   
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