华北克拉通中东部基底构造单元的重磁特征

系统收集并重新处理了华北克拉通中东部的重磁资料,利用处理结果,结合近年来华北克拉通前寒武纪结晶基底构造研究的进展,重新将华北克拉通中东部划分为2个一级重磁异常单元和7个二级重磁异常单元;重点描述了7条分划性断裂的重磁特征,特别指出中国东部重力梯度带正是华北克拉通中部带的集中表现,而郯庐断裂带和兰考～聊城～盐山～台安-大洼断裂带是燕山期陆内不同刚性块体调整的重要边界,所以也是重磁特征的变异带．据此,对华北克拉通断裂与构造单元的重磁异常特征赋予了新的地质意义．研究表明,华北克拉通现今的地球物理特征能够反映结晶基底构造,其原因是华北克拉通现今构造格局是中新生代构造继承结晶基底构造的结果．     

Carbon pools and fluxes in the China Seas and adjacent oceans

The China Seas include the South China Sea, East China Sea, Yellow Sea, and Bohai Sea. Located off the Northwestern Pacific margin, covering 4700000 km~2 from tropical to northern temperate zones, and including a variety of continental margins/basins and depths, the China Seas provide typical cases for carbon budget studies. The South China Sea being a deep basin and part of the Western Pacific Warm Pool is characterized by oceanic features; the East China Sea with a wide continental shelf, enormous terrestrial discharges and open margins to the West Pacific, is featured by strong cross-shelf materials transport; the Yellow Sea is featured by the confluence of cold and warm waters; and the Bohai Sea is a shallow semiclosed gulf with strong impacts of human activities. Three large rivers, the Yangtze River, Yellow River, and Pearl River, flow into the East China Sea, the Bohai Sea, and the South China Sea, respectively. The Kuroshio Current at the outer margin of the Chinese continental shelf is one of the two major western boundary currents of the world oceans and its strength and position directly affect the regional climate of China. These characteristics make the China Seas a typical case of marginal seas to study carbon storage and fluxes. This paper systematically analyzes the literature data on the carbon pools and fluxes of the Bohai Sea,Yellow Sea, East China Sea, and South China Sea, including different interfaces(land-sea, sea-air, sediment-water, and marginal sea-open ocean) and different ecosystems(mangroves, wetland, seagrass beds, macroalgae mariculture, coral reefs, euphotic zones, and water column). Among the four seas, the Bohai Sea and South China Sea are acting as CO_2 sources, releasing about0.22 and 13.86–33.60 Tg C yr~(-1) into the atmosphere, respectively, whereas the Yellow Sea and East China Sea are acting as carbon sinks, absorbing about 1.15 and 6.92–23.30 Tg C yr~(-1) of atmospheric CO_2, respectively. Overall, if only the CO_2 exchange at the sea-air interface is considered, the Chinese marginal seas appear to be a source of atmospheric CO_2, with a net release of 6.01–9.33 Tg C yr~(-1), mainly from the inputs of rivers and adjacent oceans. The riverine dissolved inorganic carbon (DIC) input into the Bohai Sea and Yellow Sea, East China Sea, and South China Sea are 5.04, 14.60, and 40.14 Tg C yr~(-1),respectively. The DIC input from adjacent oceans is as high as 144.81 Tg C yr~(-1), significantly exceeding the carbon released from the seas to the atmosphere. In terms of output, the depositional fluxes of organic carbon in the Bohai Sea, Yellow Sea, East China Sea, and South China Sea are 2.00, 3.60, 7.40, and 5.92 Tg C yr~(-1), respectively. The fluxes of organic carbon from the East China Sea and South China Sea to the adjacent oceans are 15.25–36.70 and 43.93 Tg C yr~(-1), respectively. The annual carbon storage of mangroves, wetlands, and seagrass in Chinese coastal waters is 0.36–1.75 Tg C yr~(-1), with a dissolved organic carbon(DOC) output from seagrass beds of up to 0.59 Tg C yr~(-1). Removable organic carbon flux by Chinese macroalgae mariculture account for 0.68 Tg C yr~(-1) and the associated POC depositional and DOC releasing fluxes are 0.14 and 0.82 Tg C yr~(-1), respectively. Thus, in total, the annual output of organic carbon, which is mainly DOC, in the China Seas is 81.72–104.56 Tg C yr~(-1). The DOC efflux from the East China Sea to the adjacent oceans is 15.00–35.00 Tg C yr~(-1). The DOC efflux from the South China Sea is 31.39 Tg C yr~(-1). Although the marginal China Seas seem to be a source of atmospheric CO_2 based on the CO_2 flux at the sea-air interface, the combined effects of the riverine input in the area, oceanic input, depositional export,and microbial carbon pump(DOC conversion and output) indicate that the China Seas represent an important carbon storage area.     

华北降水年代际变化特征及相关的海气异常型

利用近50年华北地区26个站逐月降水观测资料和全球大气海洋分析资料,分析了华北降水的年代际变化特征及其和全球海气系统年代际变化的关系.对华北降水距平指数变化分析表明,近50年来华北降水具有减少的总体趋势,叠加在该趋势之上的是年代际变化,其中1965年和1980年发生了两次跃变,使得20世纪80年代干旱尤为严重.在对华北地区降水年代际变化特征分析的基础上,揭示了与华北降水年代际异常相伴随的大气环流和上层海洋热力异常型.结果表明,华北降水年代际异常与太平洋上层海洋热力状况异常有显著关系,主要表现为太平洋年代际振荡（PDO）与华北降水异常的相关.在年代际时间尺度上,华北干旱与上层海洋热力及大气环流异常的配置关系如下：当华北地区干旱时,则热带中东太平洋海温偏高,北太平洋中部海温偏低,即太平洋上主要表现为PDO暖位相,全球大部分地区（包括华北地区）气温偏高,青藏高原地区气温偏低,日本北部及东西伯利亚气压异常偏低,华北及其以南大片地区气压偏高,华北地区由异常西北风控制,不利于水汽向华北地区输送.     

北京市应急避难场所的空间布局与服务效能评估

基于GIS空间分析技术和实际调查数据,通过构建避难场所综合服务效能指数,对北京市应急避难场所的空间分布特征及其服务效能进行了评估。结果表明:北京市应急避难场所分布具有明显的空间不均匀性,其综合服务效能大体可以分为4个层级,综合服务效能最低的地区主要集中于北京城市发展新区和生态涵养发展区。北京市避难场所总体分布与人口分布趋势基本一致,但其总体设计容量远低于需求容量,且区域间差异明显。北京市主城区基本都是避难场所服务配置缺口面积较高的区域。综合考虑多方面影响因素,加强避难场所布局与人口避难需求之间的协调统一,是提高应急避难场所服务效能的根本途径。     

Vegetation and soil carbon storage in China

This study estimated the current vegetation and soil carbon storage in China using a biogeochemical model driven with climate, soil and vegetation data at 0.5° latitude-longitude grid spatial resolution. The results indicate that the total carbon storage in China's vegetation and soils was 13.33 Gt C and 82.65 Gt C respectively, about 3% and 4% of the global total. The nationally mean vegetation and soil carbon densities were 1.47 kg C/m2 and 9.17 kg C/m2, respectively, differing greatly in various regions affected by climate, vegetation, and soil types. They were generally higher in the warm and wet Southeast China and Southwest China than in the arid Northwest China; whereas vegetation carbon density was the highest in the warm Southeast China and Southwest China, soil carbon density was the highest in the cold Northeast China and southeastern fringe of the Qinghai-Tibetan Plateau. These spatial patterns are clearly correlated with variations in the climate that regulates plant growth and soil organi     

亚洲夏季风水汽输送的年际年代际变化与中国旱涝的关系

利用1958～2002年的NCEP-R1和ERA-40逐日再分析资料以及中国160站点月平均降水资料探讨了亚洲夏季风水汽输送的年际年代际变化及其与中国降水异常的关系. 分析结果表明,亚洲夏季风水汽输送和中国夏季降水的异常主模态呈现显著的准两年变化周期. 当南亚夏季风纬向水汽输送偏强（弱）时,东亚—西北太平洋地区水汽输送的偶极型异常有利于长江中下游地区和江淮流域的水汽辐合负（正）异常与华南和华北地区的水汽辐合正（负）异常,从而引起中国东部的经向三极子雨型,即长江中下游地区和江淮流域的偏旱（涝）与华南和华北地区的偏涝（旱）. 1970s年代末之后,亚洲夏季风水汽输送的年代际减弱与西北太平洋地区水汽输送的偶极型异常相配合,导致长江中下游地区的持续偏涝与华南和华北地区的持续偏旱. 从中国夏季降水异常与水汽通量辐合异常的同相对应关系来看,ERA-40资料对亚洲夏季风水汽输送年际年代际变化的描述能力强于NCEP-R1资料.     

中国平均降水和极端降水对气候变暖的响应:CMIP5模式模拟评估和预估

基于24个CMIP5全球耦合模式模拟结果,分析了中国区域年平均降水和ETCCDI强降水量(R95p)、极端强降水量(R99p)对增暖的响应.定量分析结果显示,CMIP5集合模拟的当代中国区域平均降水对增温的响应较观测偏弱,而极端降水的响应则偏强.对各子区域气温与平均降水、极端降水的关系均有一定的模拟能力,并且极端降水的模拟好于平均降水.RCP4.5和RCP8.5情景下,随着气温的升高,中国区域平均降水和极端降水均呈现一致增加的趋势,中国区域平均气温每升高1 ℃,平均降水增加的百分率分别为3.5%和2.4%,R95p增加百分率为11.9%和11.0%,R99p更加敏感,分别增加21.6%和22.4%.就各分区来看,当代的区域性差异较大,未来则普遍增强,并且区域性差异减小,在持续增暖背景下,中国及各分区极端降水对增暖的响应比平均降水更强,并且越强的极端降水敏感性越大.未来北方地区平均降水对增暖的响应比南方地区的要大,青藏高原和西南地区的R95p和R99p增加最显著,表明未来这些区域发生暴雨和洪涝的风险将增大.     

中国遥感的回顾与展望

概要地回顾了我国自上世纪50年代以来的遥感研究，主要讨论近二十年来的遥感发展进程，并对新世纪我国遥感发展作出展望。     

Compressional elastic wave velocities of serpentinized pyroxenite at high pressures and high temperatures and its geological significance

Elastic wave velocity measurement in rocks at high pressures and high temperatures plays a key role in researching the state, properties and movement of the earth interior materials. Nowadays dehydration is believed to be as one of the most important reasons responsible for the abnormality of seismic velocity (Kern, 1982; Ito, 1990; Christensen, 1989; Popp, Kern, 1993; SONG, et al, 1996; ZHOU, 1998; ZHAO, et al, 1996). Geophysical, geochemical and mineralogical data have revealed that on…     

2011年日本9.0级地震的同震位错以及震后应力松弛过程对中国大陆的影响

本文基于日本GEONET的GPS观测资料, 对日本2011年9.0级地震的同震和震后形变过程进行了研究。 结果表明, 日本9.0级地震使中国大陆出现了显著的同震位移, 几乎对整个中国大陆都有影响。 位移量在中国东北地区最大, 接近甚至超过该地区的年运动速率。 震后1年观测到的形变基本上可由沿着断层面的蠕滑进行模拟, 粘弹松弛的贡献不大。 根据所得到的震后蠕滑模型, 震后1年形变所释放的能量等同于发生一个8.7级地震, 其影响主要在东部地区, 最大位移约为年运动速率的30%。 预测在未来2年, 该地震的影响范围将逐渐减小。 地震造成的粘弹松弛在未来50~100年的尺度上, 对东北地区有拉张效应。 日本9.0级地震整体上起到了卸载中国大陆在板块间挤压过程中所累积应变能的作用, 因此该地震发生后的几个月, 中国大陆东部的地震活动水平较震前明显降低。     

中国东部海域及邻区岩石层地幔的P波速度结构与构造分析

利用中国大陆东部及台湾地区、日本和琉球群岛的地震观测数据,通过体波地震层析技术反演了中国东部海域及其邻近地区的P波速度结构.以此为依据分析了不同地区的岩石层性质和深部动力学条件,探讨了中朝与扬子块体、扬子与华夏块体在海区的深部边界及其构造属性,揭示出菲律宾海板块与欧亚大陆的碰撞以及板片俯冲下沉、弧后扩张作用对中国东部海域岩石层结构的影响.结果表明,中国东部海域的岩石层地幔存在明显的横向非均匀性,它们与区域构造的形成演化有一定的联系.中国大陆东部的五莲－青岛断裂与朝鲜半岛西缘断裂、济州岛南缘断裂共同构成中朝和扬子块体的边界,江绍断裂向东延伸至朝鲜半岛南端成为分隔扬子和华夏块体的边界;东海陆架与冲绳海槽的岩石层结构差异明显,东海陆架具有中国东部地区的岩石层特征,属于欧亚大陆向海域的延伸;冲绳海槽的岩石层强烈减薄,为大陆向大洋过渡的区域;沿着日本－琉球－台湾俯冲带,菲律宾海板块俯冲下沉引起的地幔扰动对中国东部海域产生了较大的影响,欧亚大陆与菲律宾海板块之间的相互碰撞导致台湾地区岩石层明显增厚.     

大跨开合屋盖风荷载与风致响应试验与数值计算研究

为研究屋盖开孔对大跨结构风效应的影响,在边界层风洞中开展了大跨开合屋盖刚性模型风洞测压试验,分析了结构表面风荷载分布特征,基于时域分析法研究了屋盖开合对风致响应的影响。结果表明:大跨结构模态密集,第一阶模态能量最大,高阶成分的贡献不容忽视;屋盖开洞能有效的减小屋面风荷载,降低位移响应与加速度响应,减小风振系数。研究结果可为大跨开合屋盖风荷载设计提供参考。     

Physiographic and geological characteristics of shelves in north and west of Taiwan

In north of Taiwan the East China Sea Shelf extends from the coastline of mainland China to the southern Okinawa Trough, showing a shelf-slope-basin bathymetric profile. Sea floor of the East China Sea Shelf is generally smooth and flat. It is wide (230 km) and relatively shallow with an average shelf-break depth of 120 m, reflecting the effect of Quaternary glaciation about 15000 years ago. The Pliocene-Quaternary East China Sea Shelf is underlain by thin sequences of about 1000 m thick shallow marine sediments mainly derived from China, forming an eastward dipping sedimentary wedge due to regional tilting and subsidence and representing the youngest part of the Cenozoic rift margin in southeastern China. The Taiwan Strait Shelf has two phases in development: one is the early phase of the Paleocene-Miocene rift margin and the other is the late stage of the Pliocene-Quaternary foreland sedimentation. It is a foreland shelf and its present morphology results from the combined effects of tectonic subsidence and sedimentation overprinting that of the Late Pleistocene glaciation about 15000 years ago.     

The neotectonic deformation and earthquake activity in Zhuanglang river active fault zone of Lanzhou

Introduction Zhuanglang river active fault zone, which located in the western of Zhuanglang river valley, north of Hekou, the Xigu district of Lanzhou city, is composed of several echelon small faults, these faults display not very clear on surface. Predecessors thought that this fault from Yongdeng to Hekou was active in Late Pleistocene and even in Holocene through limited research works, they also believed that these earthquakes with magnitude 641 happened at Yongdeng and magnitude 521 …     

Cambrian integrative stratigraphy and timescale of China

The Cambrian Period is the first period of the Phanerozoic Eon and witnessed the explosive appearance of the metazoans, representing the beginning of the modern earth-life system characterized by animals in contrary to the Precambrian earth-life system dominated by microbial life. However, understanding Cambrian earth-life system evolution is hampered by regional and global stratigraphic correlations due to an incomplete chronostratigraphy and consequent absence of a highresolution timescale. Here we briefly review the historical narrative of the present international chronostratigraphic framework of the Cambrian System and summarize recent advances and problems of the undefined Cambrian stage GSSPs, in particular we challenge the global correlation of the GSSP for the Cambrian base, in addition to Cambrian chemostratigraphy and geochronology. Based on the recent advances of the international Cambrian chronostratigraphy, revisions to the Cambrian chronostratigraphy of China, which are largely based on the stratigraphic record of South China, are suggested, and the Xiaotanian Stage is newly proposed for the Cambrian Stage 2 of China. We further summarize the integrative stratigraphy of South China, North China and Tarim platforms respectively with an emphasis on the facies variations of the Precambrian-Cambrian boundary successions and problems for identification of the Cambrian base in the different facies and areas of China. Moreover, we discuss stratigraphic complications that are introduced by poorly fossiliferous dolomite successions in the upper Cambrian System which are widespread in South China, North China and Tarim platforms.     

褶皱冲断带时空演化动力学过程的数值模拟

利用库仑临界锥角理论和沙箱物理模拟进行褶皱冲断带的研究时,通常忽略了楔形体介质的内聚力.岩石力学实验结果表明,岩石内聚力通常在几到几十兆帕范围内变化.楔形体介质强度的变化是否会影响褶皱冲断带的时空演化?针对这一问题,我们建立了岩石内聚力分别是10 MPa、20 MPa和50 MPa的3个二维弹塑性有限元模型,模型包含了楔形体介质的弹塑性材料非线性和底部滑脱带的接触非线性.该模型考虑了不同介质强度、底部滑脱带摩擦、重力和边界构造加载的影响,更为符合实际.计算结果表明,岩石内聚力为10 MPa时,楔形体内的断坡首先在楔形体近端产生,从近端依次向远端发展;岩石内聚力是20 MPa时,断坡开始在楔形体近端产生,随后在远端也开始形成,最后由两端向中间汇聚;岩石内聚力是50 MPa时,断坡先从楔形体远端形成,从远端向近端依次发展.我们还讨论了底部滑脱层倾角对褶皱冲断带演化的影响,结果表明较低的底部滑脱面倾角易产生由近端向远端演化的样式,中等滑脱面倾角易产生两端向中间演化的样式,较高滑脱面倾角易产生由远端向近端演化的样式.我们得到了三种不同的褶皱冲断带时空演化的模式,其结果可以用来解释青藏高原东北缘依次向北东方向发展的海原-六盘山断层、天景山断层、烟筒山断层系统的时空演化.

     

中国东北地区剩余重磁异常特征与地质构造及成矿带的关系

在分析中国大陆宏观格架、全国布格重力异常和东北地区1:50万剩余重、磁力异常的基础上,结合东北地质及构造演化史,分析了东北剩余重磁异常特征,并探讨了剩余重磁异常特征与地质构造的关系.总结了与成矿有关的剩余重磁场特征,说明了剩余重磁异常可在刻画地质构造、断裂分布、地层分布及成矿带方面提供重要的参考信息.     

井下甚宽频带地震仪研制内容与创新

井下甚宽频带地震观测能获取来自地球内部微弱的、丰富的、准确的宽频带地壳活动信息,包括地层微破裂、慢地震等,对地震学、地震预报和相关学科均有重要的科学研究意义和实际应用价值。研制具有我国自主知识产权的井下甚宽频带地震仪,并推进其工程化、产业化是地震观测仪器发展的重要方向之一。本文介绍了国家重点研发项目重大科学仪器设备开发专项 “井下甚宽频带地震仪的研制与应用开发” 的研究目标、研究内容及主要创新点。项目首次在国内外成功研制了可应用于2000 m深井观测的、完全自主知识产权的甚宽频带地震仪,并将在国家级重大项目中示范应用,打破了国外在井下甚宽频带地震观测的领先地位,促进了国内地震观测科学技术的发展。项目的主要进展将在项目专题中的4篇文章中分别进行介绍。      

SRES B2情景下中国区域最高、最低气温及日较差变化分布特征初步分析

本文利用Hadley气候预测与研究中心的区域气候模式系统PRECIS进行中国区域气候基准时段(1961～1990年)和SRES B2情景下2071～2100年(2080s)最高、最低气温及日较差变化响应的分析.气候基准时段的模拟结果与观测资料的对比分析表明：PRECIS具有对中国区域最高、最低气温及日较差的模拟能力,能够模拟出中国区域最高、最低气温及日较差的局地分布特征.对SRES B2情景下相对于气候基准时段的最高、最低气温及日较差变化响应分析表明：中国区域2080s时段年、冬季和夏季平均最高、最低气温变化均呈一致增加的趋势,北方地区增温幅度普遍大于南方地区.夏季东北地区极端高温事件发生的频率将会增加,而冬季华北地区极端冷害事件发生频率将会减少.未来中国区域年平均日较差将出现北方地区减小而南方地区增加的趋势.冬季长江中下游以南地区日较差呈增加趋势,而夏季华东地区、西北地区及内蒙古中部日较差将呈减小趋势,其中在青藏高原北部地区存在一个较强的低值中心.     

南海东北部及其邻近地区的Pn波速度结构与各向异性

利用中国地震台网和ISC台站1980～2004年的地震数据,反演了南海东北部及其邻近地区的Pn波速度结构和各向异性.上地幔顶部的速度变化揭示出区域地质构造的深部特征：华南地区速度较高并且变化平缓,具有构造稳定地区的岩石层地幔特征;华南沿海尤其是滨海断裂带附近出现低速异常,表明该断裂可能穿过壳幔边界深达上地幔顶部.南海北部至台湾海峡较高的速度与华南地区类似,反映出大陆边缘和陆架地区的岩石层地幔性质;西沙海槽附近较高的速度不仅反映了华南大陆向南的延伸,而且与海槽裂谷拉张引起的地幔上拱有关,整个南海北部没有发现大规模地幔热流的活动痕迹.相比之下,南海东部次海盆的上地幔顶部存在明显的低速异常,对应于海底扩张中心的地幔上涌区,表明岩石层地幔强烈减薄甚至缺失;台湾东部－吕宋－菲律宾北部的低速异常与地震、火山活动以及岩浆作用紧密相关,揭示了西太平洋岛弧俯冲带的活动特征;南海东北部的洋－陆边界清晰,南海东部和菲律宾海西部较高的速度代表了海洋岩石层地幔的性质.Pn波各向异性反映出区域性构造应力状态及岩石层地幔的变形痕迹：华南地区的各向异性较小,说明这一构造稳定地区的岩石层地幔变形程度较弱;南海北部的快波方向与地壳浅表层构造的伸展方向一致,主要反映了中、新生代以来的大陆边缘张裂和剪切作用对岩石层地幔结构的影响;琉球－台湾－吕宋岛弧两侧各向异性十分强烈,平行于海沟的快波方向表明菲律宾海板块和欧亚大陆的相互作用导致俯冲板块前缘的岩石层地幔强烈变形;台湾东南海域快波方向的变化可能与欧亚大陆和菲律宾海板块俯冲机制的转换以及岩石层被撕裂有关.