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51.
1961—2010年我国夏季高温热浪的时空变化特征 总被引:11,自引:0,他引:11
利用全国753个站1961—2010年夏季逐日最高气温资料和基于死亡率明显增加而制定的高温热浪指标的已有研究成果,统计分析了我国高温热浪频次、日数和强度的时空分布特征。结果表明:我国的高温热浪频次、日数、强度高值区基本相同,均在江淮、江南大部和四川盆地东部等地,其中江西北部、浙江北部高温热浪频次最高,高温日数最多;浙江北部高温强度尤为突出。近50年来我国夏季高温热浪的频次、日数和强度总体呈增多、增强趋势,但也呈现明显的阶段性变化特征,20世纪60—80年代前期高温热浪频次和强度呈减少(弱)趋势,80年代后期以来,高温热浪频次和强度呈增多(强)趋势。区域变化特征明显,华北北部和西部、西北中北部、华南中部、长江三角洲及四川盆地南部呈显著增多(强)趋势;而黄淮西部、江汉地区呈显著减少趋势。自20世纪90年代以来,我国高温热浪的范围明显增大。 相似文献
52.
气象参数对人体舒适度的影响研究 总被引:2,自引:0,他引:2
为研究气象参数对人体舒适度的影响,用慕尼黑人体热量平衡模型(MEMI)分析了南京舒适感的概率分布、年际、月际变化以及气象参数和生理等效温度(PET)的相互关系。结果表明:各舒适感觉出现的频率差别较大,在年际分布上有波动,月际分布上很不均匀。PET随温度线性增加,在多云天气1m/s风速时增幅最大;PET和平均辐射温度之间也是线性增加关系,温度较高时增幅大;PET随着风速的增加呈现先快后慢的非线性减小关系,低温时降幅明显,高温阴天时降幅最小;相对湿度在高温时可使PET显著增加。 相似文献
53.
Zhang Xuhui Shao Qianqian Ding Yuanjun Cheng Kun Bian Rongjun Liu Xiaoyu Zheng Jufeng Li Lianqing Pan Genxing 《地球科学进展》2016,31(10):1012-1020
2015 is the International Year of Soil (IYS) adopted by the 378th Congress of the United Nations. The Status of the World’s Soil Resources was released by the Food and Agriculture Organization of the United Nations, which was the policy report about the status of the world soil resources for the first time. The universal values of the global community were strengthened by the challenges for the global society from the risk and safety of the change of soil quality, functions, services and soil health. One third of the world soil resources were suffering serious degradation, which could affect the food security in the future, regional development and local conflicts in the report. The major task of the global monitoring, regulation and management of the world soil resources and the social responsibility of supporting the sustainable soil management by education, research and technology development were highlighted. The social responsibility and global development trends of soil science and management strategies were discussed by the keywords, the distribution of contributing authors and the citation of the references, as well as the main contents of the report. The keywords distribution of the report showed that the focus of the soil research included the change of soil quality, processes, functions and services induced by the natural driving forces, human’s activity and soil degradation, as well as the hotspots covered soil carbon/nitrogen-water-biological pool and distribution related with the biogeochemistry, global climate change and ecosystem functions and human health. The number and structure of the cited papers showed that the integration research based on the mega-data analysis were the prominent development trend of the soil science. The geographic distribution of all the contributing authors showed that dominant discourse of the global soil science were grasped by the developed countries including Europe and the United States, China had just limited effects on the global soil science. It is urgent to promote China’s soil science research and the services for global society. 相似文献
54.
LI Yong YAN Liang SHAO Chongjian WANG Zhengjiang YAN Zhaokun YU Qian ZHOU Rongjun LI Haibin 《《地质学报》英文版》2017,91(2):379-395
Depending on the analysis of the coeval sedimentary geometry and subsidence mechanism in the Longmen Shan foreland basin, three models about the coupling relationship between Longmen Shan uplift and foreland basin subsidence since the Indosinian have been proposed: (1) crustal shortening and its related wide wedge-shaped foreland basin, (2) crustal isostatic rebound and its related tabular foreland basin, and (3) lower crustal flow and its related narrow wedge-shaped foreland basin. Based on the narrow wedge-shaped foreland basin developed since 4 Ma, it is believed that the narrow crustal shortening and tectonic load driven by lower crustal flow is a primary driver for the present Longmen Shan uplift and the Wenchuan (Ms 8.0) earthquake. 相似文献
55.
Active Tectonics of the Longmen Shan Region on the Eastern Margin of the Tibetan Plateau 总被引:14,自引:0,他引:14
ZHOU Rongjun LI Yong Alexander L.DENSMORE Michael A. ELLIS HE Yulin LI Yongzhao LI Xiaogang 《《地质学报》英文版》2007,81(4):593-604
There is a massive amount of geomorphic evidence for active tectonics in the Longmen Shan at the eastern margin of the Tibetan plateau. We have surveyed some typical geomorphic markers including the Wenchuan-Maowen, Beichuan-Yingxiu and Pengxian-Guanxian faults, terrace offsets, scarps, fault-controlled saddles, dextral shutter ridges, dextral channel offsets, graben, shatter belts, and pull-apart basins. Electron spin resonance (ESR) and thermoluminescence(TL) ages were obtained using silty sand taken from below the surface of the sediments. According to these data, we calculated the rates of thrusting and strike-slip, and the results indicate that Cenozoic tectonic shortening at the plateau margin is minor with the rate of thrusting less than 1.10 mm/a and the rate of strike-slipping less than 1.46 mm/a. The Longmen Shan is a zone of NNE-trending dextral shear with slip-dip ratio of 6:1-1.3:1. From NW to SE, the thrust component becomes smaller, whereas the strike-slip component becomes larger. 相似文献
56.
LI Yong YAN Zhaokun ZHOU Rongjun YAN Liang DONG Shunli SHAO Chongjian LAURENCE Svirchev 《《地质学报》英文版》2018,92(1):56-73
This study examines the relationship between high positive isostatic gravity anomalies (IGA), steep topography and lower crustal extrusion at the eastern margin of the Tibetan Plateau. IGA data has revealed uplift and extrusion of lower crustal flow in the Longmen Shan Mountains (the LMS). Firstly, The high positive IGA zone corresponds to the LMS orogenic belt. It is shown that abrupt changes in IGA correspond to zones of abrupt change of topography, crustal thickness and rock density along the LMS. Secondly, on the basis of the Airy isostasy theory, simulations and inversions of the positive IGA were conducted using three-dimensional bodies. The results indicated that the LMS lacks a mountain root, and that the top surface of the lower crust has been elevated by 11 km, leading to positive IGA, tectonic load and density load. Thirdly, according to Watts’s flexural isostasy model, elastic deflection occurs, suggesting that the limited (i.e. narrow) tectonic and density load driven by lower crustal flow in the LMS have led to asymmetric flexural subsidence in the foreland basin and lifting of the forebulge. Finally, based on the correspondence between zones of extremely high positive IGA and the presence of the Precambrian Pengguan-Baoxing complexes in the LMS, the first appearance of erosion gravels from the complexes in the Dayi Conglomerate layer of the Chengdu Basin suggest that positive IGA and lower crustal flow in the LMS took place at 3.6 Ma or slightly earlier. 相似文献
57.
四川盆地中三叠统雷口坡组勘探已近40年,但迄今为止只发现了两个大中型气藏.近年来,雷口坡组钻井油气显示活跃,展示了良好的勘探前景.四川盆地中三叠统气藏储层主要位于底部雷一段、顶部雷三一雷四段,天然气主要来源于上二叠统龙潭组和上三叠统须家河组烃源岩,各气藏天然气组分特征也不尽相同,储集空间均以各类次生溶蚀孔隙为主,多为低-中孔低渗的孔隙型或裂缝一孔隙型储层.气藏盖层发育,均具备良好的直接盖层和区域盖层条件.上三叠统马鞍塘组储层主要位于其顶、底部的(藻)砂屑灰岩和泥晶灰岩,烃源岩和盖层与雷三、雷四段成藏条件相似.本文将四川盆地中三叠统一上三叠统马鞍塘组生储盖组合特征概括为两种类型:1)上二叠统龙潭组烃源岩+雷一-雷二段滩相储层+雷口坡组膏盐盖层;2)上三叠统烃源岩+雷三-雷四段-马鞍塘组底部(礁)滩相储层和(或)风化壳古岩溶储层+上三叠统泥质盖层.将来的油气勘探应更加重视对第二组合的关注.龙门山中南段前缘地区应是中三叠统雷三一雷四段和上三叠统马鞍塘组油气勘探最有利的地区. 相似文献
58.
我国东部中低山区第四纪冰川的存在与否一直存在争议,但冰川必然对山体进行冰蚀作用形成冰蚀地貌。为了分析我国东部中低山区的山体地貌是否具有冰蚀特征,该文选取了现代冰川集中发育区—喜马拉雅山脉作为冰蚀地貌的研究对象,通过宏观分析,除了由缩口、三角脊、残弧组成的冰斗系统外,还发现冰蚀作用过程存在避谷、吞脊、切壁、穿梁等特殊习性。分析认为冰蚀过程主要受制于雪线高程、积雪高程与坡向坡角三方面因素的控制。以此为基础,对我国东部的江西庐山、山东蒙山、大兴安岭主峰黄岗梁三个地区的山体地貌进行对比分析,发现这些山区的山体地貌与喜马拉雅山脉的冰蚀地貌具有一致性。文章从冰蚀过程的角度确认了我国东部中低山区存在第四纪冰川的事实。 相似文献
59.
三维地震波场模拟——稳定波束与克希霍夫积分近似 总被引:2,自引:0,他引:2
稳定波束法,是一种适合于多层复杂介质模型地震波场模拟的快速精确方法,它基于一种稳定快速的射线追踪技术,利用反射/透射和绕射波的迭加来近似波动理论的结果。本文阐明了稳定波束法模拟的结果可视为克希霍夫积分的近似解,并简述了三维稳定波束地震波场方法研究的新进展 相似文献
60.