Water discharge variability of Changjiang （Yangtze） and Huanghe （Yellow） Rivers and its response to climatic changes

Influences of large-scale climatic phenomena, such as the E1Nifio/La Nifia-Southem Oscillation （ENSO） and the Pacific Decadal Oscillation （PDO）, on the temporal variations of the annual water discharge at the Lijin station in the Huanghe （Yellow） River and at the Datong station in the Changjiang （Yangtze） River were examined. Using the empirical mode decomposition-maximum entropy spectral analysis （EMD- MESA） method, the 2- to 3-year, 8- to 14-year, and 23-year cyclical variations of the annual water discharge at the two stations were discovered. Based on the analysis results, the hydrological time series on the inter- annual to interdecadal scales were constructed. The results indicate that from 1950 to 2011, a significant downward trend occurred in the natural annual water discharge in Huanghe River. However, the changes in water discharge in Changjiang River basin exhibited a slightly upward trend. It indicated that the changes in the river discharge in the Huanghe basin were driven primarily by precipitation. Other factors, such as the precipitation over the Changjiang River tributaries, ice melt and evaporation contributed much more to the increase in the Changjiang River basin. Especially, the impacts of the inter-annual and inter-decadal climate oscillations such as ENSO and PDO could change the long-term patterns of precipitation over the basins of the two major rivers. Generally, low amounts of basin-wide precipitation on interannual to interdecadal scales over the two rivers corresponded to most of the warm ENSO events and the warm phases of the PDO, and vice versa. The positive phases of the PDO and ENSO could lead to reduced precipitation and consequently affect the long-term scale water discharges at the two rivers.     

廊固凹陷近岸水下扇特征及控制因素

通过对廊固凹陷18口井541 m岩心的系统观察、156口井测井序列的建立、1km×1 km三维地震测网密度的地震相识别,分析了该沉积体系的相带展布特征。该砂砾岩层总体趋势为向上厚度减薄、层数减少,共识别出5期扇体,多呈条带状沿大兴断层断面分布,每期之间发育稳定的暗色泥岩段。该近岸水下扇的形成受3级层序、大兴断层、古构造、古气候、古地形以及物源供给等多种因素的控制。3级层序的发育特点、大兴断层的分段活动以及特殊的物源供给背景因素的匹配对近岸水下扇形成起到决定性作用。2~3期扇体扇中分布范围广,储集条件好,是凹陷下一步开发工作的有利目标。     

Biogenic silicate accumulation in sediments, Jiaozhou Bay

1 INTRODUCTION Silicate, or silicic acid (H4SiO4), is a very im- portant nutrient in the ocean. Unlike other major nu- trients such as phosphate and nitrate or ammonium, which are needed by almost all marine plankton, silicate is an essential chemical req…     

MISCELLANY

The geomorphic sciences will continue to be dynamic in the coming decade. Among other developments, there is a trend toward increased dependence on field reserch, more realistic expectations from reserch tools, a resurgence of interest in man-land relations with a renewed dependence on the historical approach, a reinvestigation of morphogenetic regions, study of planetary surfaces other than earth's, and involvement with applied problems, as well as cooperation and collaboration with scientists in related fields. The greatest need is the development of connections between academic and nonacademic geographers at all levels.     

SOME IMPORTANT CHARACTERISTICS OFSURFACE ALBEDO OF CHINA IN RECENT YEARS

Sdsealbedoisdefinedasaratioofreflectivesolarradiationtototalacradiation,whichcanindicatetheaborptionandreflectivecapabilityofthe~hforsolarradiation.Itisan~tfactortoinfluencethes~radiationbalance,espeiallyfortheformationandvariationoflocalndcroclirnate.Generally,theactualdatafromo~tionalstationSforrebationareedintheanalysisofsolacealal.HOwever,therepresentativenessOfthedateisIratedduetothescarcityofobservationalstationandunevendistributionofs~condition.Afterthe1960s,theanalysisfors~ealbedoise…     

2003年异常气候对清徐葡萄的影响

气候对葡萄生长发育的影响十分关键，以光照、温度和降水三要素为主。利用清徐地面气象资料，根据葡萄各生育阶段对气候资源的需求特点，比照该时期年内的实际气候状况，着重分析年度内气候异常与葡萄产量下降、品质降低之间的关系，并就如何减缓气候对葡萄生产的不利影响进行初步探讨。     

当前国内酸雨研究进展

回顾了我国在酸雨研究方面所获得的成果,包括酸雨的时空分布特征、影响因素、生态影响模拟以及控制对策等4个方面的内容。大量的研究表明,近些年来酸雨污染的范围有所增加、程度有所加重。酸雨的形成是多种自然和人为因素共同作用的结果,与特定的气象条件、天气类型和大气环流等有密切的关系。针对酸雨污染有所加重的趋势,必须采取有效的控制对策。     

岩浆核杂岩和变质核杂岩特征对比及控矿实例——南秦岭牛山-凤凰山变质核杂岩和牛山北岩浆核杂岩构造群落及控矿模式

以南秦岭牛山-凤凰山变质核杂岩和牛山北岩浆核杂岩为例, 通过核杂岩的构造群落、变质程度、岩浆侵位与变形时代、构造层次与演化、控矿特征与控矿构造-蚀变岩相填图及测年研究, 对比2类核杂岩的特征及其控矿作用。结果表明, 2类核杂岩有相似的结构样式, 但构造群落和演化差别较大。牛山-凤凰山变质核杂岩核部为新元古代武当岩群和耀岭河岩组中深变质岩, 其中可见新元古代石英闪长岩和加里东期辉石岩-辉绿岩株, 说明是在新元古代或加里东期形成的。核杂岩与外围震旦系—泥盆系浅变质岩间由剥离断层及韧性剪切带分割。志留系梅子垭岩组为浅变质强变形的岩片组合, 发育多层次韧性剪切、固态流变、滑脱-逆冲-走滑变形3期新生面理及其置换。而牛山北岩浆核杂岩核部和外围是浅变质岩, 在核部和外围填图、测试时发现新元古代、早古生代、三叠纪、侏罗纪4期侵入岩, 与岩浆核杂岩相关的有三叠纪—早侏罗世二长花岗岩株和晚侏罗世花岗岩脉2期侵入岩。研究发现, 与岩浆核杂岩伴随的岩浆侵位、韧性剪切变形与热变质增温-变斑晶加大-自然金沿S2面理分布-金矿化热液蚀变等的时代均集中在晚三叠世—侏罗纪, 指示了时代较新的陆内造山期岩浆核杂岩的脆-韧性剪切变形-立交桥式岩浆-热力垂向增生-热液蚀变成矿时空关联特点及深部找矿方向。     

西湖凹陷油气成藏的主控因素

西湖凹陷位于东海大陆架边缘,地壳为相对软弱的过渡壳。西湖凹陷中新世末以前属于萎缩型盆地,上新世伴随冲绳海槽的形成才成为扩张性盆地。受构造控制盆地萎缩期沉积有以下3个特点：第一,整体表现为海退;第二,沉积范围逐次减小;第三,泥岩百分比越来越低,盖层条件越来越差。平湖组存在区域盖层,钻遇断块气藏;花港组存在局部盖层,背斜充满度高,断背斜充满度低,断块未成藏;新近系盖层条件更差,断背斜亦未能成藏。由此可见保存条件是西湖凹陷油气成藏的主控因素,保存条件好的领域是西湖凹陷下一步勘探的方向。     

复杂载荷作用下立管触地段损伤管道的动力响应

触地段(Touchdown zone, TDZ)是在役钢悬链线立管(Steel catenary riser, SCR)的关键部位,在复杂载荷作用下,极易形成损伤缺陷,其载荷寿命的评估是深海结构工程中的一个关键问题。本文以大型有限元软件ABAQUS为平台,运用损伤管道实体单元与土弹簧阻尼单元相互作用的模型模拟触地段损伤海底管道在复杂载荷作用下的动力响应,数值计算考虑了管-土相互作用过程中的材料非线性、几何非线性以及接触非线性。讨论了单一环向体积损伤位于触地段管道的不同位置时,触地段损伤管道在不同载荷作用下的动力特性及特征点的动力响应。结果表明,管道所受内外压力以及管道提升端的竖向位移载荷会影响结构的自振频率;体积损伤部位的动力响应较完好部位更剧烈;体积损伤的位置和动力载荷频率对管道动力放大系数的影响很大;当动力载荷的激励频率越接近结构基频时,损伤管道的动力响应及动力放大系数越大。