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451.
Formation rates of Subantarctic mode water and Antarctic intermediate water within the South Pacific 总被引:1,自引:0,他引:1
Corinne A. Hartin Rana A. FineBernadette M. Sloyan Lynne D. TalleyTeresa K. Chereskin James Happell 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(5):524-534
The formation of Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW) significantly contributes to the total uptake and storage of anthropogenic gases, such as CO2 and chlorofluorocarbons (CFCs), within the world's oceans. SAMW and AAIW formation rates in the South Pacific are quantified based on CFC-12 inventories using hydrographic data from WOCE, CLIVAR, and data collected in the austral winter of 2005. This study documents the first wintertime observations of CFC-11 and CFC-12 saturations with respect to the 2005 atmosphere in the formation region of the southeast Pacific for SAMW and AAIW. SAMW is 94% and 95% saturated for CFC-11 and CFC-12, respectively, and AAIW is 60% saturated for both CFC-11 and CFC-12. SAMW is defined from the Subantarctic Front to the equator between potential densities 26.80-27.06 kg m−3, and AAIW is defined from the Polar Front to 20°N between potential densities 27.06-27.40 kg m−3. CFC-12 inventories are 16.0×106 moles for SAMW and 8.7×106 moles for AAIW, corresponding to formation rates of 7.3±2.1 Sv for SAMW and 5.8±1.7 Sv for AAIW circulating within the South Pacific. Inter-ocean transports of SAMW from the South Pacific to the South Atlantic are estimated to be 4.4±0.6 Sv. Thus, the total formation of SAMW in the South Pacific is approximately 11.7±2.2 Sv. These formation rates represent the average formation rates over the major period of CFC input, from 1970 to 2005. The CFC-12 inventory maps provide direct evidence for two areas of formation of SAMW, one in the southeast Pacific and one in the central Pacific. Furthermore, eddies in the central Pacific containing high CFC concentrations may contribute to SAMW and to a lesser extent AAIW formation. These CFC-derived rates provide a baseline with which to compare past and future formation rates of SAMW and AAIW. 相似文献
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The jet structure of the Southern Ocean front south of Australia is studied in stream-coordinate with a new altimeter product—Absolute Dynamic Topography (ADT) from AVISO. The accuracy of the ADT data is validated with the mooring data from a two-year subantarctic-front experiment. It is demonstrated that the ADT is consistent with in-situ measurements and captures the meso-scale activity of the Antarctic Circumpolar Current (ACC). Stream-coordinate analysis of ADT surface geostrophic flows finds that ACC jets exhibit large spatio-temporal variability and do not correspond to particular streamfunction values. In the circumpolar scope ACC jets display a transient fragmented pattern controlled by topographic features. The poleward shift of jet in streamfunction space, as revealed by a streamwise correlation method, indicates the presence of meridional fluxes of zonal momentum. Such cross-stream eddy fluxes concentrate the broad ACC baroclinic flow into narrow jets. Combined with a recent discovery of gravest empirical mode (GEM) in the thermohaline fields, the study clarifies the interrelationship among front, jet and streamfunction in the Southern Ocean. 相似文献
454.
为了解决导航电子地图数据生产成本高昂、更新周期长等问题,提出了由导航变化数据发现、分析、采集、制作、发布构成的导航电子地图增量式更新闭环服务模式,将公众和导航数据用户等非专业数据生产人员纳入到导航电子地图数据维护和更新框架,可以提高数据的现势性,而且大大地降低生产和应用成本,为导航电子地图服务提供了一种可操作性强的参考... 相似文献
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西藏扎西康锌多金属矿床地质特征及银的赋存状态研究 总被引:3,自引:1,他引:2
扎西康锌多金属矿床位于西藏特提斯喜马拉雅板片的"金锑多金属"成矿带东段。研究显示,矿体主要呈脉状、透镜状产于近南北向的张性断裂中。热液成矿作用主要可划分为早、晚2个成矿阶段,7个成矿亚阶段,早期以铅锌矿化为主,晚期以锑(铅)矿化为主。岩矿石镜下鉴定和电子探针分析表明,扎西康矿床矿石种类繁多,矿物组合和成矿元素均呈现明显的分带现象,由深至浅(W→E)为含锡(铁)闪锌矿+铁锰碳酸盐+少量方铅矿+少量黄铜矿(深部)→(铁)闪锌矿+铁锰碳酸盐+少量方铅矿+黄铁矿+毒砂+少量银黝铜矿+少量石英(中深部)→方铅矿+闪锌矿+脆硫锑铅矿+铁锰碳酸盐+硫锑铅矿+少量银黝铜矿+石英(中部)→辉锑矿+方铅矿+少量闪锌矿+石英+少量铁锰碳酸盐(浅部),对应的元素分带为Zn(Pb+Ag+Cu+Sn)→Zn(Pb+Ag)→Zn+Pb(Sb+Ag)→Pb+Sb+Ag+Zn。矿区银矿化主要集中在Ⅴ号矿体ZK2703-ZK2302、ZK1502-ZK1105和ZK806三个区域,与铅锑矿化关系密切。矿石中银主要以类质同象的形式存在,独立银矿物相对较少。其中,类质同象银主要赋存在方铅矿中,少量赋存在硫锑铅矿、脆硫锑铅矿、毒砂、黄铁矿等金属硫化物中;独立银矿物有少量的银黝铜矿、硫锑铅银矿、银(含银)硫铜锑矿。成矿流体中铅、锌、锑、银的运移和富集沉淀是受体系中温度、压力、浓度、pH值等多种因素综合控制的结果。 相似文献
457.
贵州苗龙金矿床毒砂中金的赋存状态研究 总被引:3,自引:2,他引:1
苗龙矿区赋矿地层为寒武系上统三都组灰岩和泥灰岩,矿体严格受断裂构造控制,矿体主要赋存于东西向Fm1、Fm14断裂中。矿床成矿作用可划分为3个期次,即沉积成岩期、热液成矿期和表生氧化期。毒砂为热液成矿期主阶段重要产物之一,主要呈菱形体、针状、柱状及放射柱状集合体产出。通过对毒砂进行电子探针分析及面扫描分析,结果表明毒砂中主成分稳定,w(Fe)为32.47%~35.71%,平均34.05%;w(S)为21.01%~26.38%,平均为23.13%;w(As)为38.50%~44.73%,平均为41.86%。其成分(FeAs0.80S1.17~FeAs1.02S1.21)明显偏离理论毒砂的成分(FeAs1.12S1-x≤|0.13|),具有富硫亏砷等低温热液特征。毒砂含金性较好,w(Au)为0.05%~0.14%,平均为0.06%。面扫描图像中,Au元素分布均匀,说明Au主要以晶格金(固溶体金)形式存在于毒砂中。 相似文献
458.
The study deals spatial mapping of earthquake hazard parameters like annual and 100-years mode along with their 90% probability of not being exceeded (NBE) in the Hindukush–Pamir Himalaya and adjoining regions. For this purpose, we applied a straightforward and most robust method known as Gumbel’s third asymptotic distribution of extreme values (GIII). A homogeneous and complete earthquake catalogue during the period 1900–2010 with magnitude MW ⩾ 4.0 is utilized to estimate these earthquake hazard parameters. An equal grid point mesh, of 1° longitude X 1° latitude, is chosen to produce detailed earthquake hazard maps. This performance allows analysis of the localized seismicity parameters and representation of their regional variations as contour maps. The estimated result of annual mode with 90% probability of NBE is expected to exceed the values of MW 6.0 in the Sulaiman–Kirthar ranges of Pakistan and northwestern part of the Nepal and surroundings in the examined region. The 100-years mode with 90% probability of NBE is expected to exceed the value of MW 8.0 in the Hindukush–Pamir Himalaya with Caucasus mountain belt, the Sulaiman–Kirthar ranges of Pakistan, northwestern part of the Nepal and surroundings, the Kangra–Himanchal Pradesh and Kashmir of India. The estimated high values of earthquake hazard parameters are mostly correlated with the main tectonic regimes of the examined region. The spatial variations of earthquake hazard parameters reveal that the examined region exhibits more complexity and has high crustal heterogeneity. The spatial maps provide a brief atlas of the earthquake hazard in the region. 相似文献
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460.
本文从断裂组合、火山机构和岩浆通道等方面分析,提出徐家围子断陷基底断裂及与之匹配的次级断裂控制白垩纪火山活动,形成受基底断裂控制的三个 NNW 向展布的火山岩发育带。由于基底断裂特征不同,各火山岩带分别具有中心式、裂隙式和复合式三种不同的喷发特征。徐家围子断陷安达地区精细解剖表明,其基底断裂上部发育 NWW 向雁列式断裂,向下沟通基底断裂,为西部火山岩浆上侵通道,反映了历史时期内火山活动西强东弱的特征,西部火山规模大,以爆发相为主,东部为大面积溢流相。火山岩的分布受基底断裂及沟通其的次级断裂控制,同时对断裂痕迹起到一定的改造作用。 相似文献