中国西北C-3植物的碳同位素组成与年降雨量关系初探

 本文对不同年降雨量环境下生长的藜、独行菜、魁蓟和平车前这4种常见C-3植物的δ¹³C进行了分析,发现这4种C-3植物的δ¹³C组成都表现出随年降雨量减少而变重的趋势,其中藜和独行菜的碳同位素组成对降水变化的响应相对要较其它2种植物强烈得多。藜、独行菜和魁蓟的δ¹³C组成与年降雨量有显著的线性关系,平车前碳同位素组成与年降雨量没有显著的相关性,表明藜、独行菜和魁蓟的δ¹³C组成可作为年降雨量的替代性指标,平车前的δ¹³C组成不能作为年降水的替代性指标。     

澜沧江上游德钦县亚高山、高山草地群落类型及其特点

摘要：采用样方调查方法获得94个草地群落样方,对澜沧江上游德钦县亚高山、高山草地群落类型及其特点进行了初步分析。结果表明,该县亚高山、高山草地群落类型存在20个类型。在放牧干扰下,大多数群落类型处于退化状态,相互之间存在明显的群落替代关系;调查发现群落中每平方米内平均含8种草本植物,平均盖度62．4％,地上平均生物量是4859kg／hm^2,平均可食率为61．5％;鸢尾群落、牛旁群落和小狼毒群落是草地严重退化后形成的典型有毒害群落类型;长期的高强度放牧虽然增加了群落类型多样性,但减少了群落内物种多样性。总体而言,长期的放牧干扰降低了德钦草地的生物多样性的质量及其生态服务功能,导致草地生态系统的非持续发展。     

Annual ENSO simulated in a coupled ocean–atmosphere model

Using an output from 200-year integration of the Scale Interaction Experiment of EU project-F1 model (SINTEX-F1), the annual ENSO reproduced in the coupled general circulation model is investigated, suggesting the importance of reproducing an annual cycle in realistically simulating ENSO events. Although many features of the annual ENSO are reproduced, the northward expansion of sea surface temperature anomaly (SSTA) in the eastern tropical Pacific stays south of the equator. It is suggested that this model bias is due to the excitation of the too strong Rossby waves in the southeastern tropical Pacific, which reflect at the western boundary and intrude into the eastern equatorial Pacific. The zonal wind stress anomaly along the equator also plays an important role in generating the equatorial Kelvin waves. The amplitude of SSTA for the annual ENSO mode is reproduced, but its variance is only 20% of the observation; this is again due to the lack of northward migration of seasonal SSTA in the equatorial region and weaker coastal Kelvin waves along South America. Remedies for the model bias are discussed.     

平凉C11井水位异常变化的地震前兆信息分析

着重分析1998年以来平凉C11井水位在西海固一平凉地区5次Ms〉4．0地震前的异常特征。通过分析得到的认识是，该井水位在Ms4．0以上地震前大都存在0．5a以上的趋势异常和年变规律的变化，震前1～2个月出现较丰富的短临前兆信息，如水位固体潮畸变、日潮差波幅增大、阶跃等微动态异常，这些分析结果曾在地震预报实践中发挥较好的作用。     

猪野泽记录的季风边缘区全新世中期 气候环境演化历史*

通过季风边缘区石羊河古终端湖猪野泽QTL剖面年代学及沉积物粒度、碳酸盐、有机碳、碳氮比和有机质稳定同位素等多项气候代用指标的综合分析,建立了季风边缘区9~3cal.kaB.P. 的古气候演化序列。结果表明,9cal.kaB.P. 到7.8cal.kaB.P. 期间,流域的水分条件和温度逐渐上升,植被状况好转,此时气候逐渐转暖湿;而在7.8~7.5cal.kaB.P. 出现了显著的百年尺度的干旱事件,沉积物主要以砂质沉积为主,此时湖泊生产力显著下降;全新世期间最为暖湿的气候适宜期出现在7.5~5.0cal.kaB.P.;约5.0cal.kaB.P. 以来,该区域出现了较为明显的干旱化趋势。另外,对猪野泽地区的白碱湖的湖泊地貌学和年代学研究表明该区域在7.5~5.0cal.kaB.P. 出现了3次高湖面,并且湖岸堤时序变化指示了全新世后半期湖泊逐渐退缩的过程进而指示该区域出现了显著的干旱化趋势。     

Characteristics of seasonal and spatial variations of primary production over the southeastern Bering Sea shelf

In situ primary production data collected during 1978–1981 period and 1997–2000 period were combined to improve understanding of seasonal and spatial distribution of primary production in the southeastern Bering Sea. Mean daily primary production rates showed an apparent seasonal cycle with high rates in May and low rates in summer over the entire shelf of the southeastern Bering Sea except for oceanic region due to lack of data. There was also an increasing trend of primary production rates in the fall over the inner shelf and the middle shelf. There was a decreasing trend of primary production rates between late April and mid-May over the inner shelf while there was an abrupt increase between late April and mid-May over the middle shelf and the outer shelf. In the shelf break region, there was an increasing pattern in late May. These suggest that there was a gradual progression of the development of the spring phytoplankton bloom from the inner shelf toward the shelf break region. There was also a latitudinal variability of primary production rate over the middle shelf, probably due to either spatial variations of the seasonal advance and retreat of sea ice or horizontal advection of saline water in the bottom layer. Annual rates of primary production across the southeastern Bering Sea shelf were 121, 150, 145, 110, and 84 g C m⁻² yr⁻¹ in the inner shelf, the middle shelf, the outer shelf, the shelf break, and oceanic region, respectively. High annual rates of primary production over the inner shelf can be attributed to continuous summer production based on regenerated nitrogen and/or a continuous supply of nitrogen at the inner front region, and to fall production. There were some possibilities of underestimation of annual primary production over the entire shelf due to lack of measurement in early spring and fall, which may be more apparent over the shelf break and oceanic region than the inner shelf, the middle, and the outer shelf. This study suggests that the response of primary production by climate change in the southeastern Bering Sea shelf can be misunderstood without proper temporal and seasonal measurement.     

含油气盆地成藏动力学研究综述

成藏动力学是石油地质领域一个研究热点，是一门新兴的学科，目前在国内外均没有明确、统一的定义。笔者介绍了成藏动力学的产生、发展与研究现状，论述了成藏动力学的定义、划分原则、类型及命名等基本内容，并总结出了其研究思路和方法，指出了成藏动力学下一步研究的主要内容和发展趋势。认为在进一步认识与油气成藏密切相关的化学动力学、流体动力学过程和机理的基础上，实现盆地温度场、压力场、应务场的耦合和流体流动、能量传递和物质搬动的三维模拟，是成藏动力学的重要发展方向。     

福建省及其沿海和台湾海峡频度统计与分析

本文采用空间扫描方法 ,按选区和时段做震级—频度统计 ,计算年平均地震数。通过比较与分析 ,得出三点初步结论     

厦门台地倾斜年变畸变现象与1994年东山海外7.3级地震

1994年 9月 1 6日东山海外 7 3级地震前一年左右 ,厦门台地倾斜E -W分量年变发生严重畸变 ,正常年变规律图象明显被破坏 ,异常出现后 1 1个月 ,东山海外发生强震。该现象可以作为闽粤近海强震的一个重要前兆指标     

Spatial organization of decadal and bidecadal rainfall fluctuations in southern North America and southern South America

The spatial organization of decadal and bidecadal components (fluctuations) of annual rainfall is identified in this research for two regions: (1) southern South America, and (2) southern North America (conterminous USA, southeastern Canada and northern and central Mexico). Findings indicate that these decadal and bidecadal components have highly coherent wave-like spatial organization. Two types of organization of decadal and bidecadal components of annual rainfall were identified: a train of propagating fluctuations and quasi-standing fluctuations. For decadal components, such patterns alternate in time. A widespread change in the spatial organization of decadal component of annual rainfall took place simultaneously in both continents in 1932. The bidecadal component is organized as standing fluctuations in southern North America and as travelling fluctuations in southern South America, The spatial pattern of decadal fluctuations of annual rainfall has 12- and 13-year cycles, and the spatial pattern of bidecadal fluctuations has predominantly 21- and 22-year cycles.