中国近海生态环境变化的同位素示踪研究

同位素在确定物质来源、指示生物地球化学循环路径、定量生物地球化学过程速率等方面具有独特的优势,本文以近海生态环境变化研究中常用的稳定同位素（13C、15N、18O）和放射性核素（14C、234Th、232Th、230Th、228Th、210Po、210Pb、137Cs、226Ra、228Ra、224Ra、223Ra）为对象,介绍它们在揭示海洋有机质来源、食物网结构、水体缺氧机制、氮循环过程、颗粒动力学、海底地下水输入、有机地球化学过程、沉积年代学等方面的应用,侧重于总结我国近海生态环境研究中同位素示踪取得的进展。伴随着我国经济的发展,近百年来我国近海生态环境也发生了明显的变化,基于同位素示踪揭示的近海富营养化和沉积环境的演变规律表明,我国近海生态环境自20世纪50年代起经历持续的变化,特别是在过去20~30年时间里,近海生态环境的变化尤为剧烈,反映出人类活动是我国近海生态环境变化的主要驱动力。未来需要通过发展新的同位素技术及拓展更广泛的应用,围绕近海海洋生态环境变化的突出问题,重点揭示近海生态环境变化的响应特征、变化速率和作用机制,从而系统地掌握近海生态环境的时空变化规律。     

陈代光教授对岭南历史地理研究的贡献

陈代光教授是我国一位著名历史地理学者.文章主要论述其在岭南广州、港澳、雷州等城市、南海海上丝绸之路交通、区域历史地理、广东历史地图集编纂、地名、中国历史地理教材建设、历史地理人才培养,以及历史地理为社会经济发展服务等方面的学术成就和重要贡献,以作为对陈代光教授的一种纪念,同时唤起社会各界对这门又古又今、既要看书、又要走路的学科的关注.     

北大西洋地区气候准20年周期的观测和模拟分析

北大西洋地区除了存在约70 a周期的AMO（Atlantic Multidecadal Oscillation,北大西洋年代际振荡）之外,历史长期气候记录中英格兰温度（Central England Temperature,CET）与格陵兰冰芯净雪累计率还存在显著的20 a周期波动。本研究利用CCSM4（Community Climate System Model version 4）耦合模式工业革命前控制试验（piControl）结果中的海表面温度（Sea Surface Temperature,SST）,通过10～50 a带通滤波与扩展经验正交函数（Extended Empirical Orthogonal Function,EEOF）分解,得到在北大西洋副极地海区存在准20 a振荡的逆时针旋转模态。此周期与其临近地区的CET、格陵兰冰芯净雪累计率的准20 a振荡周期相吻合,说明这种北大西洋副极地海区准20 a振荡的海洋模态与其临近地区的大气准20 a振荡之间可能存在相应的联系。进一步利用CAM4（the Community Atmosphere Model version4）大气模式,以北大西洋副极地海区准20 a振荡SST旋转模态为强迫场进行敏感性试验,进一步验证了这种联系。     

1958-2017年太湖蒸发量年际变化趋势及主控因子

湖泊蒸发对气候变化非常敏感,是水文循环响应气候变化的指示因子,因此研究湖泊蒸发的控制因素,对于理解区域水文循环有重要意义.本文利用太湖中尺度涡度通量网避风港站观测数据校正JRA-55再分析资料,驱动CLM4.0-LISSS模型,并利用2012-2017年涡度相关通量数据和湖表面温度数据检验模型模拟蒸发结果,验证了该模型在太湖的适用性;估算了1958-2017年间太湖的湖面蒸发量,并利用Manner-Kendall趋势检验分析了湖面蒸发的变化趋势,寻找太湖实际蒸发的年际变化的主控因子.结果如下:校正后的JRA-55再分析资料模拟的太湖蒸发与观测值之间存在季节偏差,但是季节偏差在年尺度上相互抵消,再分析资料可用于年际尺度太湖蒸发变化的模拟;1958-2017年间太湖蒸发量以1977年为界,先下降(-3.6 mm/a),后增加(2.3 mm/a);多元逐步回归结果表明,向下的短波辐射是太湖1958-2017年间太湖蒸发变化的主控因子,向下的长波辐射、气温、比湿也对湖泊蒸发年际变化有一定影响,但是风速对蒸发量的年际变化影响不大.     

Passive microwave remote sensing of the historic February 2010 snowstorms in the Middle Atlantic region of the USA

The snowfall in the Baltimore/Washington metropolitan area during the winter of 2009/2010 was unprecedented and caused serious snow‐related disruptions. In February 2010, snowfall totals approached 2 m, and because maximum temperatures were consistently below normal, snow remained on the ground the entire month. One of the biggest contributing factors to the unusually severe winter weather in 2009/2010, throughout much of the middle latitudes, was the Arctic Oscillation. Unusually high pressure at high latitudes and low pressure at middle latitudes forced a persistent exchange of mass from north to south. In this investigation, a concerted effort was made to link remotely sensed falling snow observations to remotely sensed snow cover and snowpack observations in the Baltimore/Washington area. Specifically, the Advanced Microwave Scanning Radiometer onboard the Aqua satellite was used to assess snow water equivalent, and the Advanced Microwave Sounding Unit‐B and Microwave Humidity Sounder were employed to detect falling snow. Advanced Microwave Scanning Radiometer passive microwave signatures in this study are related to both snow on the ground and surface ice layers. In regard to falling snow, signatures indicative of snowfall can be observed in high frequency brightness temperatures of Advanced Microwave Sounding Unit‐B and Microwave Humidity Sounder. Indeed, retrievals show an increase in snow water equivalent after the detection of falling snow. Yet, this work also shows that falling snow intensity and/or the presence of liquid water clouds impacts the ability to reliably detect snow water equivalent. Moreover, changes in the condition of the snowpack, especially in the surface features, negatively affect retrieval performance. Copyright © 2011. This article is a U.S. Government work and is in the public domain in the USA.     

A 200-year precipitation index for the central English Lake District / Un indice de précipitation de 200 ans pour la Région des Lacs en Angleterre

Abstract

Abstract The geographical context and hydroclimatology of the English Lake District means that the region is an important monitor of changes to nationally significant environmental assets. Using monthly rainfall series for sites in and around the central Lake District, a continuous ~200-year precipitation index was constructed for a representative station close to Grasmere. The bridged series shows a significant decline in summer rainfall since the 1960s, offset by increases in winter and spring that are strongly linked to North Atlantic forcing. Over longer time periods, the index exhibits several notable dry (1850s, 1880s, 1890s, 1930s, 1970s) and wet (1820s, 1870s, 1920s, 1940s, 1990s) decades. These patterns are strongly reflected by reservoir inflow series and by indicators of the biological status of the region’s freshwater lakes. It is argued that long-term climate indices will become increasingly important as managers seek to evaluate recent and project environmental changes within the context of long-term natural variability.     

Subduction and back-arc activity at the Hikurangi convergent Margin,New Zealand

The Hikurangi Margin is a region of oblique subduction with northwest-dipping intermediate depth seismicity extending southwest from the Kermadec system to about 42°S. The current episode of subduction is at least 16–20 Ma old. The plate convergence rate varies along the margin from about 60 mm/a at the south end of the Kermadec Trench to about 45 mm/a at 42°S. The age of the Pacific lithosphere adjacent to the Hikurangi Trench is not known.The margin divides at about latitude 39°S into two quite dissimilar parts. The northern part has experienced andesitic volcanism for about 18 Ma, and back-arc extension in the last 4 Ma that has produced a back-arc basin onshore with high heaflow, thin crust and low upper-mantle seismic velocities. The extension appears to have arisen from a seawards migration of the Hikurangi Trench north of 39°S. Here the plate interface is thought to be currently uncoupled, as geodetic data indicate extension of the fore-arc basin, and historic earthquakes have not exceededM _s=7.South of 39°S there is no volcanism and a back-arc basin has been produced by downward flexure of the lithosphere due to strong coupling with the subducting plate. Heatflow in the basin is normal. Evidence for strong coupling comes from historic earthquakes of up to aboutM _s=8 and high rates of uplift on the southeast coast of the North Island.The reason for this division of the margin is not known but may be related to an inferred increase, from northeast to southwest, in the buoyancy of the Pacific lithosphere.     

辽宁及其邻区1900—1949年M≥5级地震参数研究

我们搜集了国际国内地震台网资料、宏观考察资料、地震专题研究报告,对1900—1949年5级以上地震全部进行了核查,重新进行定位处理,并结合宏观考察资料和前人工作成果进行分析研究,得到较为准确的震中位置。通过这项研究,增补了原目录中遗漏的地震,并对目录中的错误进行了修正,从而得到一份较为完整可靠的地震目录。     

Mapping the Geographical Diffusion of a Finnish Smallpox Epidemic from Historical Population Records

Smallpox mortality from an early 19th century epidemic in Finland is mapped at the parish village level. First, geographically referenced historical materials are used to construct a map showing the spread of smallpox mortality among villages. Next, the diffusion of smallpox morbidity is simulated by computer for the same set of villages. These two maps are then compared. Results indicate that at this scale maps of mortality diffusion can show general trends but have no direct spatial correspondence to the underlying pattern of morbidity diffusion. Mortality maps cannot be used as a surrogate measure of infectious contact behavior at micro scales of analysis.